2.1 2.1.1

Theoretical Fundamentals of Training Injury Prevention and Training

As mentioned elsewhere in this F-MARC manual, there is an extensive body of information on injuries in football. We have learned many things, some obvious, some not so obvious. For example, two-thirds of all injuries occurred to the ankle, knee, head, lower leg and foot. One obvious conclusion is first aid for games; be prepared to administer first aid for ankle and knee sprains, strained (pulled) muscles, contusions, lacerations and concussions. Another interesting finding is the number of players with prior injuries. About half the players with ankle sprains had a prior sprain, many within the same season. The risk of a second ankle sprain increases by 3-5 times in players with a prior sprain. Very often, a major injury was preceded by an incompletely rehabilitated minor injury. Competitive sport is inherently risky, but we can support individual players to take appropriate precautions against injury or re-injury. For example: • Poor flexibility and muscle tightness are often cited as risk factors in muscle strains, tendon injuries and re-injuries of strained muscles. The groin, hip flexors and ankle dorsi-flexors (pointing your toe up) are often tight in football players. Players should be encouraged, therefore, not to neglect stretching these problem areas. • Ankle sprains often occur during tackling suggesting that technique may be an issue as well as fair play (many ankle injuries are from late tackles from the side). In addition, over half of those with an ankle sprain will re-injure it and half of those do so within two months of the first injury. It is good advice to follow the doctor’s and therapist’s orders about rehabilitation. Most footballers see a sprained ankle as a nuisance, but returning too soon to play places the

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player at a clear risk for another, possibly more serious, injury to the ankle or elsewhere. Protection of a sprained ankle (e.g. taping, lace-up ankle supports) for 6 months to a year or more has been suggested for the unstable ankle. Do not to try to return to play too soon. Follow rehabilitation guidelines completely to protect prior sprains or any injury. The team needs its players on the field, not on the sidelines. Risk factors of non-contact knee injuries include: • Laxity - loose ligaments due to either prior injury or genetics • Muscle imbalance - one leg being stronger than the other or the quads and hamstrings being imbalanced. • Flexibility - people with knee injuries have flexible hamstrings • General motor skills - knee ligaments seem to tear during landing, stopping or cutting in an erect stance (straight knee and straight hip) and some valgus at the knee. This is especially true in female players, who need to play with a lower centre of mass and absorb the shock of landing by flexing the hips and knees;a soft and quiet landing means the shock of ground contact has been absorbed. For coaches, these are skills that should be taught when players are young. Puberty seems to be a reasonable age to start encouraging this technique. • Low endurance has been cited as an injury risk. Injuries and goals are similar in that many occur late in games. In surveys of youth and professionals alike, a major fraction of all injuries occurred in the last 10-15 minutes of a game. Many training injuries occur during pre-season when players are unfit. So the main duty of each player is to arrive in shape, not to arrive in camp to get in shape. The

Theoretical Fundamentals of Training

25

coach will then improve fitness specifically for the game so that players do not tire as much late in the game. • Football skill is also a factor in injury. Less skilled players suffer more injuries. Skill work may seem dull, but we all know intuitively that the better skilled players are usually injured less frequently.

• Head injuries occur during head-head contact or head-ground contact, mostly in the penalty area and near the mid line (when competing for goal kicks, punts, etc.). Especially dangerous are head flicks where a player flicks the ball off the head, usually backwards. If the player who wants to head the ball does not separate from the defender, there is danger to the defender behind who

• Foul play has been implicated in injuries as up to 50% of traumatic football injuries were due to foul play; sometimes to the defensive player and sometimes to the offensive player. The most skilled and most fit players are better able to avoid these collisions. • Boys aged 11 to 14 are at a special risk. During puberty, height increases faster than muscle growth. The tall, weak boy gets injured more often than the shorter, less mature or the taller more mature boy. That “in-between” period is a problem that deserves special attention from all involved. Notice the wide range of physical maturity in an U13 team (Fig. 2.1.1). • Shin guards are required in football. While all guards will spread out the impact, they are not really helpful at preventing fractures. Shin guards that spread out the impact the most contain air/foam cell pads. Most players want the bare minimum guard to pass the referee’s inspection; however, the larger the shin guard, the more protection. As players get older, some even wear children’s shin pads because they are small and light, but pass inspection by the referee (Fig. 2.1.2). Many contusion injuries from tackling are seen in the bottom third of the lower leg that is not protected by the small children’s shin guards worn by adults. Law IV only states that a player must wear shin guards with no statements provided on size. Prevent lower leg contusions by wearing age-appropriate shin guards.

Fig. 2.1.1 US youth players

Fig. 2.1.2 Too small shin guards

Fig. 2.1.3 Head-head contact

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Theoretical Fundamentals of Training

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jumps and gets hit on the chin or on the nose by the first player performing the flick (Fig. 2.1.3). The female player on the far left (dark jersey) throws into a teammate who must head (flick) the ball over her own head. The defender (white jersey) jumps to head the ball. The player receiving the throw jumps slightly, impacts the ball and the opponent’s face/nose leading to a fractured nose and cheek plus a concussion. This action can lead to a whiplash type of injury. Perhaps a solution is to teach players to take a step back to either control the ball on their chest/thigh/foot or head it back to a teammate they can see or to teach the person throwing the ball into play to throw the ball so that it can be controlled more easily (to feet, thigh or chest). This would protect both players and be tactically better. In youth play, players usually don’t know where the flick is going anyway so it is probably a wasted pass. • A preventable goalkeeper injury in young players is a fractured wrist. This happens when an adult is shooting an adult size ball (size 5) at a younger goalkeeper. Always use the age appropriate ball and only have players of the same age take real shots on goal. Common sense can eliminate this unnecessary injury. • Another completely preventable injury is called a “de-gloving” injury of a finger. Before some games, nets need to be put on the goals and many goals have hooks in the bar for the nets. This injury happens when someone jumps to put the net over a hook in the bar and catches a ring on the hook. Gravity then leads to this injury. Never jump. Always stand on a ladder or use other suitable support. • Finally, goalpost injuries to children have led to catastrophic neck injuries and some fatalities. These happen when unsupervised children climb on portable goals and the goal tips over on a child.

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Portable goals should always be secured to the ground and children should never be allowed to play on the goals. All fatalities have occurred outside of games when the children were unsupervised. FIFA clearly states that no goal should ever be left unsecured. Many injuries, especially re-injuries in football are preventable. Preparation prior to play is important as well as decisions made during play. The main objective of any form of physical training is to elicit a physiological response that will permit the player to perform at a greater level than before and protect against injury. For any athlete attempting to undergo a period of fitness training they must adhere to certain principles in order to gain maximum benefits from their training programme. This applies to all athletes, regardless of competency and is extremely important for the injured and deconditioned because training can be more varied and complex in comparison to the fit athlete who is more consistent in their training habits. The aim of this section is to provide a breakdown of the long established training principles and their importance to the athlete who, either due to injury or a period of inactivity, has not trained consistently for a sustained period of time.

2.1.2

The Individuality of Training

The predominant factor that governs an individual’s response to exercise training is genetics as everyone responds to exercise training differently even if the training performed is identical. Some individuals respond better to endurance type training whereas others respond to shorter, more power/strength biased activities. Many research studies have examined the genetic response to exercise training and concluded that for maximal aerobic capacity, heredity can account for between 25%

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27

- 50% of the variance in VO2 max values. Improvements have been reported from 0% - 43% when a group of subjects followed the exact same endurance training programmes for up to 12 months. It has been said that “the best way to become an Olympic athlete is to be selective when choosing your parents.” Athletics is a good example of how genetics can affect a person’s sporting ability. Athletes who perform the 100m have a very different physiological make up to athletes who perform the 10,000m. These revolve around differences in body habitus, cardiovascular system and in the muscle fibre type. Sprinters have predominantly fast twitch muscle fibres (type IIa and type IIb). The characteristics of these fibre types are, fast contraction speed, high power output, very high intensity exercise and anaerobic generation of energy. Consequently, fast twitch muscle fibres can support shortterm explosive activities such as sprinting. The muscle fibre characteristics of the 10,000m runner are the opposite. The runner’s muscles are predominantly made up of slow twitch muscle fibres (type I). These muscle fibres have a slow contraction speed, low power output, are recruited for low intensity exercise and generate energy aerobically. Because of these characteristics, the slow twitch (type I) fibres are fatigue resistant. Therefore, the type I muscle fibres can support medium intensity, long duration exercise in the absence of fatigue. Most muscles contain a mixture of the various muscle fibre types and fibre type distribution varies from individual to individual. While each fibre type can be trained to a certain degree, the relative fibre type composition of muscles is a genetically determined attribute. Hence, athletic and sporting capabilities, are to a certain extent genetically predetermined.

28

Theoretical Fundamentals of Training

Initial fitness levels prior to a period of training can also govern the nature of the response. This is particularly true for the injured and deconditioned athlete. After a prolonged period of inactivity, fitness levels are lower for these individuals in comparison to athletes actively participating in their sport. Consequently, when commencing a training programme in a deconditioned state or following an injury, the gains in fitness, whether they are in endurance, strength, power etc., will be fairly rapid in comparison to the gains that a conditioned athlete achieves in their regular programmes – despite their higher fitness levels. The higher the initial level of conditioning the smaller the relative improvement for the same training programme, i.e. if two people, one fit and one unfit, perform the same training programme the unfit person will demonstrate the greater relative improvement. The more one has to improve, the more one will improve.

2.1.3

Overload

In order to bring about adaptations that are enough to elicit an improvement in physiology and, ultimately, in performance, the programme must provide a sufficient overload stimulus. This will provide the body with sufficient adaptations to training that will improve performance. Overload can only be achieved through performing exercise at a level above what the body is already conditioned to perform. The overload stimulus must also be progressive, otherwise improvements will begin to level off and performance will stagnate. For example, an athlete attempting to improve their bench press may initially perform 3 sets of 8 repetitions with a weight of 60 kilograms on the bar. As the number of training sessions performed increases, the athlete’s upper body strength will also increase and the 60 kg will feel lighter than when the exercise was first performed and the athlete will be able to perform more repetitions before fatigue sets in. There-

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Progressive overload is also a very important factor for injured and deconditioned athletes. The retraining process can occur very quickly at first, but the overload must be continued in order to return the player to competitive fitness. Otherwise the responses/adaptations to training will be less and improvements in fitness will stagnate leaving the player ill-prepared to compete. The appropriate overload can be achieved by manipulating combinations of training frequency, duration and intensity (McArdle et al. 2001).

2.1.4

Frequency, Intensity and Duration of Training

All training programmes should contain and follow the principles of frequency, intensity and duration. Improvements in fitness will occur if any of these three factors are increased. 2.1.4.1 Frequency There appears to be no precise number of times to train in order to bring about physiological improvements. The frequency of ���������������������� �����������������

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sessions depends entirely upon the goal of the training programme or session. Is the goal of the programme to improve endurance, strength, power etc.? Three non-consecutive training days a week is typically considered as the minimum necessary to improve fitness. It is also known that doing the same exercise daily can lead to overuse injury (Fig.2.1.4). That is why it is important to have rest days as well as considering a cross training day as a replacement for regular training. 2.1.4.2 Intensity The relationship between fitness improvement and exercise intensity is an S-shaped curve (Fig. 2.1.5). A small increase in intensity at the low end of the curve (left) will lead to small increases in fitness while the same relative increase in intensity at the moderate area of the curve (middle) leads to much larger increases in fitness. At the very high intensity level, an increase in intensity can lead to further, but small, gains in fitness but these are best left to the highly competitive elite athlete. 2.1.4.3 Duration Increasing the duration of training leads to increases in fitness up until about 45 minutes to 1 hour of work and then further increases in duration lead to smaller changes (Fig. 2.1.6). Again, long duration sessions are best left to the highly competitive athletes. Volume of work refers to the product of duration and frequency of training bouts, i.e., volume can be increased be either increasing the frequency

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fore, as strength improves, the athlete will need to increase the weight at which the exercise is performed in order to elicit the same overload that 60 kg once represented. As strength continues to increase, the weight used in the programme will also need to increase. Progressive overload is applicable to all forms of fitness training, aerobic and anaerobic.

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Fig. 2.1.5 Training intensity and fitness

Theoretical Fundamentals of Training

29

or the duration of sessions. This is due to the various energy systems employed to support energy production during short, medium and long term exercise at varying intensities. During high intensity training such as strength, speed or power work, where the exercise is performed at or close to maximal levels, the energy systems employed to support the exercise are predominantly anaerobic. Energy for high power output at a fast rate provides instantaneous energy at the onset of exercise, but the capacity to prolong energy provision is poor. This is either the result of depletion of ATP–PCr stores or a build-up in lactic acid or other waste products in the muscles. In order for exercise to continue, intensity needs to be reduced so that the aerobic pathway becomes the major source of energy production, thus maintaining stores of ATP and PCr whilst also minimising lactic acid levels. Therefore, when intensity is high the volume of work that can be tolerated is brief and the benefits of the training are anaerobic adaptations. The aerobic pathway of energy production has a much greater capacity and can supply energy for a much longer period, but it cannot supply energy as fast as the anaerobic pathways. Therefore, when exercise intensity is reduced to below approximately ~80-90% of maximum, the volume of work that can be tolerated is increased and hence there is an increase in exercise

Which of the three elements, intensity, frequency or duration (volume), have the greatest effect upon fitness levels? It appears that intensity is the critical factor. However, a structured training programme should feature all three elements. Studies that have examined tapering, i.e. a reduction in training in order to peak for a particular event, have reported the importance of exercise intensity when attempting to maintain fitness levels. One study reported that after a reduction of 67% in training volume and frequency while maintaining intensity, fitness levels were maintained for an amazing 15 weeks! This was achieved because the remaining exercise in the programme was performed at a high intensity and as soon as intensity levels were reduced, fitness levels began to fall. Other studies have produced similar findings which all lead to the conclusion that for frequency, duration and intensity, intensity is the critical factor of fitness during regular training.

2.1.5

Specificity of Training and Cross Training

The principle of specificity has a major role in the physiological responses to training, the adaptations that occur following training and the mechanism of fatigue.

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2.1.5.1 Specificity of exercise A specific exercise elicits a specific response. The heart rate response of running 100m is different from the heart rate response of running 5,000m. In football, the best way to mimic the game is to play the game.

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Fig. 2.1.6 Duration of training and fitness

30

duration. The adaptations to which will be predominantly aerobic.

Theoretical Fundamentals of Training

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2.1.5.2 Specificity of training A specific training programme will lead to specific adaptations. The adaptation to a resistance-training programme will be different from the muscle adaptation to a

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distance running programme. In football, the best way to train for the game is to do activities of the game. Distance running during the season will train a player to be a distance runner, not a footballer.

training. Consequently, cross training is a mode of exercise that aids training when a programme’s normal activities are not possible and this is a popular mode of training for injured and deconditioned athletes.

2.1.5.3 Specificity of fatigue The reason an athlete fatigues (fails to maintain a desired power output) when lifting weights is different from the reason an athlete fatigues when running a marathon. Fatigue in football arises from repeated short sprints depleting muscle glycogen as well as dehydration.

Despite the principle of specificity of training, athletes may improve performance in one mode of training by training in another. The benefits of cross training for the injured and deconditioned athlete allow for the participation in training even if the desired mode of training is not an option! For example, cycling enables an athlete to train aerobically even if an injury prevents them from being able to run. They can maintain the cardiovascular adaptations to their training even though an injured leg might prohibit running. Does cross training have a sufficient benefit to be included in the training programme of injured and detrained athletes?

Ideally training should, as close as possible, mirror the movements and energy systems necessary for the sport in order for peak performance to be achieved. This applies not only to the energy systems required for the sport, but also the muscles and movement patterns of the sport. The principle of specificity is not simply confined to aerobic or anaerobic forms of exercise training. Many research studies have demonstrated that training responses are specifically related to the nature of the training activity as little improvement is observed when the response is measured during a dissimilar mode of exercise. For example, Magel et al. (1975) studied the aerobic improvements following swimming training when the subjects were measured during swimming and running tests. The swimming test demonstrated an 11.2% improvement in aerobic capacity whereas the running test only elicited an increase of 1.5%. Therefore, the specificity principle is most effectively achieved when the athlete trains the specific muscles and energy systems involved (McArdle et al. 2001). 2.1.5.4 Cross training Whilst the adaptations that occur following exercise are greatest when the activity employed is specific to the activity which is being trained for, it may not be possible, either due to injury or poor fitness levels for an athlete to mirror their sport when

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Numerous studies, employing various different modes of exercise, have examined the physiological effects of cross training with varying results. It has been reported that runners were able to maintain actual running performances by running in deep water for a period of 4 weeks. Other studies have also reported that deep water running, in common with other aerobic activities offers similar aerobic benefits when performed at the correct intensity, frequency and duration. It has been reported that even for the most serious of athletes, cross training could be a way to increase the amount of training without increasing the risk of injury. However, it has been suggested that cross training is not an activity for highly trained or serious athletes. The majority of research concerning cross training arrives at the same conclusion – that whilst cross training may demonstrate some transfer effects of training, the size of the effects will be less than those which could be attained by increasing specific training by a similar amount. However, if specificity of training is not an option, cross training should be consid-

Theoretical Fundamentals of Training

31

ered, some training is better than none at all. This is especially relevant to aerobic training. It appears that cardiac performance improvements are general (McArdle et al. 2001). Anaerobic training is entirely specific as these adaptations occur within the muscle, if the muscle is not used during training, it will not produce a training response!

2.1.6

If training is not performed due to either illness or injury, any adaptations that have occurred are lost in as brief a period as 10 days. This detraining process which occurs regardless of the pre-existing state of physical fitness, has varying effects upon aerobic and anaerobic fitness. The reduction in aerobic adaptations is considerably greater than for other performance capacities such as strength, power and flexibility. In a study of the effect of complete rest upon fitness levels, five subjects were confined to bed rest for 20 consecutive days and their VO2 max declined by 25% (approximately 1% per each day of rest). This decrease was largely brought about via a reduction in the performance of the heart. A clear illustration of detraining is highlighted in Fig. 2.1.7. Capillary density, aerobic (Krebs cycle) enzymes and ultimately ����������� VO2 max all reflect the efficiency of a per-

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Fig. 2.1.7 Effect of detraining

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Decreases in muscular endurance performance can occur very rapidly following the complete cessation of training. This appears primarily to be a function of an impaired ability of the muscles to generate energy, both aerobically and anaerobically. Reductions can occur within two weeks if immobilisation has occurred, but if muscles are still able to move freely, a minimal amount of training stimulus should be sufficient to prevent any substantial drops in muscular endurance performance. Adaptations that are lost during the detraining process are not regained during an equivalent period of retraining. If an athlete stops training for 12 days then only 75% of the enzymes responsible for aerobic metabolism are regained after 24 days of retraining. A study of the effect of 15 days detraining followed by 15 days retraining on aerobic enzymes, VO2 max and an endurance performance run time showed that the 15-day period of retraining did not return any of the variables to the pre-existing levels. Finally, there was a two minute increase (i.e. slower) in endurance performance time. The problems of retraining do not differentiate between fitness levels, as highly trained athletes and non-athletes both demonstrate a slower rate of return compared to the rates of loss. Therefore, detraining appears to far outweigh the effects of retraining. The old coaching saying ����������� therefore appears to be true: “It’s easier to ���������� stay in shape than to get in shape.” ���������������

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son’s aerobic capacity. The graph demonstrates that the adaptations that took almost two years to achieve were lost within only six months of detraining.

Theoretical Fundamentals of Training

������ Now, the question arises as to what can be done to maintain fitness; what is the least an athlete can do and still keep most of their fitness? As has been mentioned elsewhere, training is a mixture of 3 factors: training frequency (days/week), training intensity (percentage of maximum capac-

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ity) and training duration (minutes/day). All three factors have been studied and all three have to be considered when figuring out how to maintain fitness. 2.1.6.1 Reduction in frequency If training days are reduced by a third or two-thirds (that is, from six training days per week to four or two days per week) while the training intensity and duration (work as hard and as long as before) are maintained, it is possible to maintain endurance. 2.1.6.2 Reduction in intensity If training intensity is reduced by a third or 2/3 and the training frequency and duration are maintained (work as frequently and as long), there are significant reductions in endurance. 2.1.6.3 Reduction in duration If the minutes per session are reduced by a third or two-thirds (or from 40 minutes/ session to 26 or 13 minutes per session) while the training frequency and training intensity are maintained (work as hard and as often), it is also possible to maintain endurance. These results show that training frequency and duration can be reduced with little effect on overall endurance, assuming intensity is maintained. However, the quickest way to lose endurance is to reduce training intensity. Therefore, it is important to keep practising at a training intensity similar to that during the season. Following injury, joints and their surrounding musculature are often immobilised. The detraining process occurs very rapidly to these muscles. Anyone who has ever had a relatively serious injury will have noticed a certain degree of muscle wasting (atrophy) following immobilisation. Muscle size is reduced during periods of inactivity, with the loss in size consequently causing reductions in muscular strength and power. However, unlike aero-

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bic capacity, reductions in neuromuscular performance are not as rapid following detraining. Reductions in muscle strength and power are relatively small during the first few months after training has been reduced. Research evidence demonstrates no loss of strength in the first three weeks after the cessation of a three week training programme. Only 45% of the original strength gained from a 12-week training programme was lost after one year of no training. If muscles are not immobilised, then large drops in strength following periods of inactivity can be minimised. This is due to athletes being able to move around freely, supporting their own body weight and providing an exercise stimulus to the muscles. Muscles apparently require minimal stimulation to retain the strength, power and size gained during training. The detraining process appears to have a greater effect upon aerobic performance than it does upon anaerobic performance (strength, power and muscular endurance). The decrements are primarily due to a reduction in the ability to generate energy aerobically. Strength, power and muscular endurance can all be maintained to a certain degree via one high intensity training session per week. However, for aerobic capacity to be maintained, two days a week of training are needed if the intensity of the exercise is high (85 – 100% VO2 max).

2.1.7

Principles of Recovery

One of the most crucial factors of all training programmes is that adaptations to training only occur during periods of rest. Good training programmes are all about balancing high quality work and quality rest periods. If rest and recovery are not built into a training programme, then session after session will soon become counter-productive rather than beneficial. This also applies to competition. With players on multiple teams, league games, tourna-

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ments and other competitions, the only time players get any quality rest is when they are injured. On the other hand, too much recovery will also not help to boost fitness levels, because training infrequently will not provide sufficient overload to boost performance. Thinking back to the principle of overload, training must provide a workload above what the body is already accustomed to. Following exercise that has been performed to sufficient overload, the muscles and energy systems undergo physiological and structural changes that permit them to reset to a higher level, thus gaining the benefit of the exercise. This process of recovery involves the repletion of energy stores, repair of structural muscle damage and recovery for the nervous system which tends to take longer to recover than muscles. If the central nervous system is still in a fatigued state during subsequent training bouts, nerve cells will fire at a slower rate, the number of muscle fibres recruited will be less and movements will become less coordinated. The rate at which energy stores are replenished following exercise depends upon (1) the intensity at which the exercise bout was performed and (2) the energy systems that supported the exercise. Both of these factors go hand in hand. Muscle ATP and PCr stores are repleted within a matter of minutes following exhaustive exercise; however, carbohydrate stores may take up to 2 days to return to the pre-exercise level following exhaustive endurance exercise (distance running) which football is not. Glycogen replenishment following exhaustive intermittent running can be repleted within 24 hours. The rate at which muscle glycogen stores are resynthesised largely depends upon the timing and quality of carbohydrate (CHO) intake following exercise. It is recommended that CHO intake should begin immediately upon termination of exercise, as the activity of the enzymes that regulate this process is greatest in the first two hours after exercise is

34

Theoretical Fundamentals of Training

completed. A high CHO diet should replenish muscle glycogen stores within 24 hours of exhaustive exercise. More details are found in the nutrition section (section 2.6) of this manual. A strenuous workout will cause a certain degree of muscle damage, or micro trauma, within the muscles. This damage is repaired as the muscles undergo the adaptations that occur following training. However, if another training session is performed before the muscles have had the chance to repair, the problem of insufficient rest occurs. Structural repair of damaged muscle, however, is one of the fastest adaptations to exercise and training. The amount of protein resynthesis can illustrate the extent to which muscle tissues rebuild following damage that has occurred during training. Studies have demonstrated that following extensive exercise, the muscle protein synthesis rate increases by 50% four hours after exercise and can climb to a 109% after 24 hours. Finally, the rate of muscle resynthesis returns to baseline levels 36 hours following heavy training. This demonstrates that it can take a period of up to 36 hours for this recovery process within the muscles to be complete and it is important that this period of recovery not be interrupted by another bout of training unless a prolonged rest period is planned after back-to-back intense training sessions, i.e. a weekend of rest. However, that is not to say that athletes must wait 36 hours in between every single training session. The recovery process will be specific to the nature of the prior training. It is common to see professional athletes training up to three times a day, but all the sessions will have a different objective, i.e. strength, power or aerobic exercise, therefore the recovery will be confined to the specific muscles and energy systems incorporated with that particular training session.

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Muscle soreness tends to be more prominent following resistance or power training than aerobic endurance training. Resistance training requires significant eccentric (lengthening) contractions that damage muscle fibres. The eccentric component of running is much less. Plus, the muscle fibre types involved in the activity have varying resistance to fatigue. Fast twitch muscle fibres are recruited during resistance training (short-term explosive exercises) and these fibres have a tendency to fatigue much faster than their slow twitch counterparts. Also during these types of training, the exercise is localised to specific muscle groups whereas aerobic training such as running spreads the work (and subsequent soreness) over a much larger muscle mass. The recovery process initiates various mechanisms that permit subsequent bouts of training to be performed to a higher level. New muscle proteins are formed which enable muscle to produce more forceful and sustained contractions. Glycogen stores within the muscles are increased as are the amount of enzymes involved in the anaerobic and aerobic production of ener-

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gy. There are many other adaptations that occur within the body during recovery following exercise and this process is termed ‘compensation’. If the process of compensation involves the return of the body to its pre-existing state, then supercompensation is a process where the body returns to a level above the pre-trained state. Over a sufficient period of time compensation eventually produces a fitter, stronger, faster and more powerful athlete. Figure 2.1.8 illustrates the supercompensation effect of exercise training. If the exercise has been performed to the correct intensity then fatigue occurs. Following training the body begins to compensate: energy stores are replenished, muscle damage repaired, etc.. If the training overload has been sufficient the body compensates and adapts to a higher level than before (supercompensation). The adaptations that occur following aerobic, anaerobic, power and resistance training will be discussed later. If too much time elapses between training sessions then the level of supercompensation is soon lost. If the recovery period is too short, sufficient time has not been allowed for compensation. If the recovery period is too long, the body can lose some of the compensation it has achieved. Low intensity aerobic training can be structured into a training programme in order to help boost recovery between strenuous training sessions. This light exercise is termed ‘active recovery’ and it aids the recovery process by increasing the blood flow through muscles that, in turn, ena����������������� � ����������������

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Following a strenuous resistance or a heavy aerobic training session, muscle soreness is commonplace. This soreness can show immediately after exercise and lasts for a few hours (acute soreness) or soreness can be delayed for hours or even days after a training session (this phenomenon is termed ‘delayed onset of muscle soreness’ or DOMS). DOMS appears to be a result of structural damage to the muscle cells (mostly during eccentric or lengthening contractions) and not only does it produce soreness but has also been demonstrated to slow the rate at which muscle glycogen is resynthesised. However, DOMS, during the early phase of a training programme, is necessary as it maximises the training response (muscles are broken down and rebuilt to a higher level) and soreness will eventually be reduced during subsequent bouts of training.

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Fig. 2.1.8 Time, fitness and length of recovery

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bles the efficient removal of any lingering waste products that may hinder the recovery process. If recovery is not an integral part of the training programme then the body will not have a chance to build on the training already performed, as physiological improvements only occur when the body is resting. In turn, subsequent bouts of exercise will be performed before recovery is complete or in a fatigued state and will be counterproductive to the training session. If the principle of recovery is not followed, it is common for athletes to develop overuse injuries, mild viral infections or experience the overreaching or overtraining syndromes. To induce ‘supercompensation’ it is necessary that each training programme contains training sessions with a sufficient degree of variation alternated with sufficient rest. A training programme can consist of training cycles of three weeks. Each cycle starts with a priming week with moderate training volume and intensity, a ‘crash’ week of higher intensity training, then a recovery-week where training intensity and volume are low.

not recover between training bouts and therefore work in a compromised state. The degree of muscle damage can manifest itself as muscle soreness, earlier onset of fatigue, muscle pain, stiffness and a higher than normal blood lactate response. All of these factors will result in a loss of strength, power and efficiency of the work being performed. Muscle damage with overtraining will also impair the muscles’ ability to restore glycogen stores thereby reducing the amount of available energy for subsequent bouts of exercise. In short, the body begins to break down and fails to fully recover by the next training overload. Other symptoms of overtraining are sleep disturbances, nausea and higher than normal heart rate and blood pressure. Along with detrimental performance, a good indicator of overtraining is the heart rate response to a standardised exercise session. In an overtrained state the heart rate response rate will be higher when compared to the response when the athlete is fit. As soon as the coach or athlete perceives that it becomes difficult to maintain the athlete’s heart rate in the high intenGet enough rest.

2.1.8

Overtraining

The consequence of too little recovery between training sessions, or too many high intensity sessions performed within a short period of time, is a concept termed ‘overtraining’. This is a psychophysiological phenomenon whereby performance is reduced despite the continuation of training. Fatigue is an unavoidable consequence of exercise and, during periods of overtraining, increased levels of physical and psychological fatigue are inevitable consequences! A reduction in performance in spite of increased training is the primary indication of overtraining. This can be a direct consequence of muscle damage as muscles do

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Theoretical Fundamentals of Training

Take adequate time to recover between work-outs. Get a full night’s sleep. Increase training load slowly. Have the players keep a training diary of the type of work-out, duration and intensity. Also what was eaten that day, how they felt while exercising. Rate the training difficulty on a 1-10 scale. Eat a balanced diet low in fat and high in complex carbohydrates. Alternate intense work-outs with lighter exercise sessions. Perform a variety of exercises. Fig. 2.1.9 Steps to prevent overtraining

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sity target zone, they should be very careful to reduce or avoid the stress of training. Alternatively, a sudden but consistent decrease or increase of the resting heart rate measured after waking up in the morning is another dangerous sign of infection or over-training. If any of these symptoms occur, it is important to contact the coach immediately to modify the training. High intensity training is strongly discouraged in the presence of any of these symptoms because high intensity training would cause a further deterioration in performance. The symptoms of overtraining are highly individualised and subjective and cannot be universally applied so the presence of any of the above symptoms should be enough to provide an indication that the athlete is either training too hard or having insufficient recovery between exercise bouts. Athletes in an overtrained state are likely to experience an increased rate of infection as overtraining can also suppress the normal immune function. Sometimes coaches need to question the athlete about how they are feeling; “Sleeping OK?”, “Feel rested when you wake up?”, “No? Must not be sleeping through the night, are you?”. In a game like football, a player that needs rest may not be truthful as they fear that days away from training might mean losing playing time to another player. Direct questions the player knows the ‘right’ answer to will not give the coach the information needed to help the athlete. Of course, their body may make the decision for them when they contract an illness due to the suppressed immune system. The treatment of overtraining consists of either a significant reduction in training intensity or complete rest, but the best cure for overtraining is prevention. Training should be structured to avoid overtraining. • Adequate recovery is an integral part of a training programme. • Mix low, medium and high intensity work. • Try not to perform too many high intensity sessions back to back.

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• Try to follow a high intensity session with a low - medium session. • Ensure an adequate CHO intake. • Try to implement low intensity aerobic sessions (some call this a regenerative session) into programmes to facilitate the recovery process. Overtraining is a syndrome that coaches of individual sport athletes (e.g. swimming, distance runners, cross-country skiers, cyclists) must be constantly concerned about. Thankfully, this syndrome is rare in football and other team sports but can occur in selected players on professional or other highly competitive teams.

2.1.9

Periodisation Concepts

Periodisation refers to the overall training plan of a team. The concepts can be applied to a calendar year, season, week, or day and are built on the interaction of training volume, training intensity and technique training during the period. Figure 2.1.10 shows the general relationship between these three factors. The training year can be divided into four conceptual phases. Each year begins at the end of the previous year with a period called “Active Rest”. During this important period players stay active, but they do activities away from the game like cycling, swimming, hiking, tennis, rollerblading, or other non-football related activities. This keeps the player active and retains some of their fitness, but takes them away from the game where overexposure might lead to staleness. The next phase is called the “Preparatory Phase” where players slowly begin to build up their fitness. The emphasis is on high volume, but low intensity training (e.g. jogging). With gradual increases in fitness, the running distance declines while the pace of running increases. The Transition Phase is the period between the more aerobic preparatory phase and the initial training camp. Here, the volume is reduced as the intensity is raised.

Theoretical Fundamentals of Training

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For example, in the early transition period; Fartlek running would be a good choice then moving into some long interval runs followed by shorter, harder intervals. The final few weeks prior to the team coming together might include a lot of repeat runs at a fast (but not sprint) pace, such as 90m in 15s with a 45s rest; the typical 1:3 work:rest formula for interval training. This running distance would be for male adult players. Decrease the running distance as needed for younger players as well as females. The idea is to run for 15 seconds at a fast pace. Start out doing 1020 of these and add a further 5-10 each week. The total number would be based on the age and playing expectations of the player and team. An U16 team might do 20-25 of these repeat runs while an adult, highly competitive player might work up to 40. The “Competition Phase” is where the coach will bring the players to match fitness with activities that closely mimic the game and give emphasis on technique, tactics and fitness. The total volume of running will be less than that of the preparation period, but the intensity will approach that necessary for the game. The phase that is probably most poorly understood is active rest. This is a critical phase for the physical development of the player. During this phase, the player continues to be active, but in different activities such as other sports and leisure time activities. This accomplishes two things. First, the activity helps the player to maintain a reasonable fitness level. Second,

this is the time for psychological and emotional rest away from the game. The body’s adaptation to training follows a predictable model; Figure 2.1.11. At the onset of training, there is a slight drop in performance due to things like muscle soreness and stiffness (the Alarm phase in the figure). Then the body begins to adapt to the new demands (the Resistance phase). Training is manipulated to maintain fitness (the Competition phase). Should the training stimulus continue to be increased while performance declines, the athlete may lapse into a detrained state (the exhaustion or overtrained phase). Once an athlete’s performance has plateaued, however, backing off the training volume and intensity and then beginning to ramp the training up again (the transition and preparation phases) can eventually lead to performance at a higher level (the new, higher Competition phase). 2.1.9.1 Off-season training Football, like most sports, is seasonal there are periods of preparation (pre-season, or preparation/transition), competition (in-season) and recovery (off-season or active rest). Pre-season and in-season training are the domain of the coach, but during the off-season it is the player’s responsibility to complete the fitness programme the coach has put together. What players do in the off-season will impact on the next season. The old coaching adage says, “it is easier to stay in shape than it is to get in shape.” Most players however,

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Theoretical Fundamentals of Training

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do not know how to maintain their fitness without a coach to supervise them. Proper planning of a year-round training programme requires some understanding of the periodisation of training concept. Cardio-respiratory endurance can be trained by specific endurance training, but it may also be challenged by non-specific endurance training; like jogging, cycling and swimming. These types of activities would be performed during the active rest phase and the beginning of the preparation phase. Non-specific endurance training is often neglected as a method for developing fitness. In between two competitive seasons, players should be encouraged to participate in other endurance exercise modes such as cycling, in-line skating, cross-country skiing and swimming in order to fully maintain and develop their fitness. Of course, the genetic component of maximal oxygen uptake is still predominant. However, the impact of this training should not be neglected. These activities not only serve to better develop fitness levels, but also mentally distract the player from the ‘addiction’ to running and playing. For speed and agility, practising other ball sports on a recreational basis (such as badminton, tennis, squash and playing 5a-side football) may result in an improved fitness level while maintaining agility. A key fact is that training activities are recreational, not competitive. 2.1.9.2 Other off-season considerations Calorie intake During the off-season, if training volume is reduced (as days per week and/or minutes per day), the number of calories burned during exercise will be reduced. To maintain weight during a period of reduced training, it is therefore a good idea to reduce food intake. There are some players who may need to lose weight to improve their performance. Do not make this decision without sound

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advice on whether weight loss is desired and get advice on nutrition and weight loss goals. Once this decision has been made, the season for weight loss is the off-season, not in-season. Trying to lose weight in-season is a quick way to poor performance and possible injury. It is much better to save weight loss for the off-season. Strength training Strength is one of the many factors that make up the concept of physical fitness and most athletes can become better in their sport if they are stronger. Strength training achieves some things, but not others. For example, the stronger player will be able to resist physical challenges better and be more resistant to injury. However, strength training is not really effective at adding distance to a goal kick or power to a shot. The off-season is the best time to improve strength and power. In this regard, the coach should identify those activities that improve a player’s overall strength and not focus exclusively on the athlete’s legs on the notion that this will improve their shooting ability (to be a better shooter, go out and shoot). Once the season begins, the goal of strength improvement gives way to the goal of strength maintenance. Rest There is a genuine concern among the football community that both youth and professional players compete in too many games each year. Games for school teams, club teams, in and out of season tournaments can mount up to the point where the only rest a player gets is when they get injured. For the professional players there is the suggestion that games be limited to 60 or fewer per year to avoid fatigue, which can lead to poor performance and injury. There is a need for planned periods of rest followed by a planned re-establishment of fitness for the next season. Rest is important, so take some time by being active, but refrain from playing football. Rest is valuable for “recharging the batter-

Theoretical Fundamentals of Training

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ies” in preparation for the push of the next season. While time away from the game is important, time off does not mean down time; it does not mean no exercise. As has been mentioned before, the fastest way to lose fitness is to reduce the intensity of training. And no player really wants to go into the early games of a season in poor shape or with rusty skills. They want to get on the field and start playing.

occurred during games. Probably the easiest and best way to prevent injuries is simply to improve the fitness of the players prior to the season. Medical professionals in multiple sports will say that fitness is one of the best ways to prevent injuries. Of course, in some sports (e.g. American Football), improved fitness has reduced some injuries while increasing others; the profile of injuries has therefore changed.

There is nothing more aggravating than to have to spend time off the field due to an injury. But most injuries can be prevented by some work prior to re-entering the field. Below some evidence is presented that both pre-season conditioning and ball skills are modifiable factors of injury prevention (not all injuries can be prevented, some injuries just happen).

Skill level Most injury studies focus on location, type and rate of injuries. Projects that investigate other factors in injuries are rare. A group of Norwegians added a skill factor to their project (Poulsen et al. 1991). Each coach was asked to grade the overall skill level of each player and then look at injuries according to that player’s skill. Interestingly, the most skilled players were the least injured and those with the poorest skill levels were the most frequently and most severely injured. The possibility of fewer, less severe injuries clearly shows there is a reasonable trade-off for a little time in the weeks prior to training. So it is important for the upcoming season to improve endurance and body control by doing lots of activities that will improve both. The healthier the individual athletes and the team, the more likely the team is to have its best players on the field; this should hopefully translate to a more successful season.

2.1.9.3 Importance of preparatory and transition phases Pre-season conditioning A recent report tracked injuries of 300 girls, aged 15-18 over two high school seasons (Heidt et al. 2000). Some of the girls participated in a 7-week pre-season conditioning programme and some did not. The training programme concentrated on endurance, strength, agility and plyometric activities. An athletic trainer recorded all injuries according to location, type (sprain, strain, etc.) and severity. The results could not be more startling. There were a total of 98 injuries with an overall injury rate of 0.3 injuries per player per season. However, of the 98 injuries, only seven were in the group that participated in the conditioning programme. In the trained group, there was one ACL tear (vs. eight in the untrained group), two ankle sprains (vs. 21) and one quad strain (vs. seven). Only one trained athlete had a season-ending injury (the ACL) while 11 of the untrained had season-ending injuries. Almost half of the injuries to the untrained players occurred in practice while five of the seven injuries to the trained players

How would these concepts be applied to the annual calendar year of a European professional team? (Fig. 2.1.12) The end of the long season might be at the end of May. The players might be given two to four weeks off and then be asked to start preparing on their own for the next season ��� �

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Fig. 2.1.12 Typical European calender

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Theoretical Fundamentals of Training

Football Medicine Manual, ©F-MARC 2005

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based on some prescribed programme by the trainer or manager. They would arrive at training camp and move into the beginning of the competition phase and games would begin in very early August. The first half of the season is played until the middle of December. During this phase, there might be some small increases in fitness. Over the winter break, the players might have two weeks of active rest, two weeks of preparation and finally two weeks of transition training. Then the second half of the season begins in early February. 2.1.9.4 The dilemma of physical training and match schedule As the season approaches, more excited coaches start to plan out the season. Books and videos of skills, drills and games are studied, selected, discarded and reconsidered until finally every minute of each training session is filled. But more planning is needed. The prime variables of training are the frequency of training (days/week), the intensity of training and the duration of training (min/day). In many cases, the frequency is somewhat fixed. A school programme might train/ play daily (five days/week as three training days and two games or four training days and one game) while a youth club team might train twice per week and plays 1-2 games over the weekend. The season does not have unlimited training time and somehow the coach must cram in technical skill training, team tactics and fitness. The next question is how all this can and should be managed. Probably, the first thing to do is to set up a calendar with game dates. The following shows a possible 4-week schedule of a professional team. Game dates are in red (Fig. 2.1.13).

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Fig. 2.1.13 Match days (red)

Obviously, everyone knows it is better not to train hard on the day before a game, so the days before a game are coloured light � � blue (Fig. 2.1.14). ���

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Fig. 2.1.14 Light training (light blue)

As many teams restrict training on Sundays, these days may be coloured yellow (Fig. 2.1.15). ���

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Fig. 2.1.15 Sundays (yellow)

Most coaches know that it is important to conduct regenerative training on the day after a game. Therefore these days are coloured green (Fig. 2.1.16). ���

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Fig. 2.1.16 Regenerative training (green)

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Theoretical Fundamentals of Training

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Finally, most people who study training know that training hard on two consecutive days is very difficult to do. So, where there are two consecutive uncoloured days, one may be coloured dark blue before the lighter of the two days (Fig. 2.1.17). ���

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Fig. 2.1.17 Light training (dark blue)

It becomes evident that because there are only three days to work on fitness� (ignore � the last Saturday), how can fitness be improved during the season? Not surprisingly, when the endurance of football players is followed over a season, there is little change throughout the season. The bulk of the improvement in fitness happens in the first third of the season (beginning with the first day of pre-season training camp), then maintained for the rest of the season. Some studies have even shown a decrease in fitness towards the end of the season. While this example is based on a European professional season, most coaches should be able to manipulate these phases to their own calendar year of training and competition. Suggestions on how to organise a single training session based on these concepts: Begin the session by following the warmup suggestions. These will help prepare the players for activity and also teach valuable lessons on controlling their body. Next, some individual ball skill training (very low intensity work) can be followed by small group work (e.g. 3v3, 4v4, 5v2, 6v4) that is at a higher intensity, then large group work (as big as your team allows up to perhaps 7v7 or 8v8). Restrictions should be placed on the format of games so the players have to run and think. This helps with their

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Theoretical Fundamentals of Training

‘game intelligence’ and minimises players standing around doing very little. Restrictions can be technical (e.g. must trap and pass with the weak foot, always pass with the outside of the foot), tactical (e.g. on offense, attackers play with their back to the goal, which teaches midfielders to come forward to shoot at goal), or fitness (e.g. two-touch speeds up the game, run 10m in any direction after any pass). Coaching books and schools teach almost endless variations in format. The coach could choose almost any drill or small group game and modify it to stress any combination of fitness, technique or tactics. For example, for low intensity training the team could play 6v6 with goalkeepers on half a field with no restrictions for about 15 minutes (technical and tactical coaching should be offered throughout). For higher intensity, mark off a 20m zone across the middle of the field. The teams play six attackers v five defenders in one end of the field with the sixth player at the opposite end of the field. When the defensive team gets the ball, they pass directly to their far team-mate and all but one from the other team sprint across the midfield and play at the other end. The game continues back and forth across the no-play zone (some call this the ‘no midfield’ game or ‘deep game’). Play this harder game for about 10 minutes. Finally, for very high intensity work, when the defenders get the ball and pass the ball across the midfield, they get two points for a goal (or one point for a shot on goal) if their entire team is in the new attacking area AND at least one opponent (other than the one who is supposed to stay) is left behind. Play this very high intensity game for maybe five minutes. The volume (time played) is dropped for each game while the intensity is raised according to the periodisation concept. Depending on the age and goals of the team, this series of games could be followed by small-sided activities then some skills and finally cool down. For more com-

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petitive teams, after a break, the routine could be repeated before easier small-sided games, skill work, then cool down.

ment of fitness is slow, the higher the ultimate level of fitness will be and the longer this level can be maintained.

The no-midfield game can be modified further. To make the transition to the other end of the field faster, make the midfield shorter (10m) for shorter, faster sprints. To encourage longer runs (and accurate long passes) increase the size of the midfield to 30 or 40 metres. Of course, other technical or tactical restrictions can be added to make the game even harder. A game need not just have one restriction. Practice games of 11v11 with no restrictions are not good for fitness training. With a typical possession in a football match being 4 players and 3 passes or less, small sided games (4v4) are very good for teaching general tactics with many ball contacts.

Improvement in running (not sprinting) speeds: If one trains by walking, walking improves. If one jogs, ability to jog AND walk improves. If a person trains at progressively faster speeds (but not sprinting speeds), they will improve their fitness at that speed and the lower speeds. That is why repeat 90m runs at a hard, but not maximal pace, are good because only about 800-1,000m (of 10,000m) are covered at a sprint by a male professional in a game, so about 9,000m are covered at speeds below a sprint. How often must high intensity training be performed? Remember the section on maintaining fitness. Intensity is the important factor. But how often? Most training specialists feel that three non-consecutive training sessions a week need to be scheduled. The competitive game should be considered as intense training. Playing one game a week means two intense sessions need to be scheduled. If there are two games, then one hard day would be scheduled. Many youth teams train twice a week and play one or two games over the weekend. The game is considered a training stimulus, so in order to get three days of hard training, there must be some high intensity work scheduled for each training session.

Special considerations to think of when planning a training Relationship between intensity and duration: It is wrong to think footballers can train hard AND long. Intensity is inversely related to duration; the harder one works, the less time they can maintain that intensity. Trying to work long and hard without rest or low intensity days can lead to overuse injuries and possibly overtraining. Rate of improvement in fitness (Fig. 2.1.18): A player can work their way up to peak condition in a short time, but the ultimate level of fitness will be low and the length of time they can maintain that fitness will be brief. However, if the develop-

Fig. 2.1.18 Improvement of fitness

How much of a training session should be devoted to high intensity training? People who study training suggest that no more than about a third of the sports specific training (i.e. not the warm-up, cool-down etc.) should be devoted to high-intensity work. For example, assume that once warm-up and supplementary activities have been done, the plan is for 90 minutes of football training. That might mean that the coach would have the training divided into low, moderate and high intensity portions. Putting all the high intensity work into one 30-minute segment would tire the

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Theoretical Fundamentals of Training

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players so that during the final 10-15 minutes of hard work, they would not be working as hard as they should be. Therefore, divide the training time in half (two 45minute periods). Now devote about 15-20 minutes of low intensity work (ball skills, small group activities. Then increase the intensity by some of the options suggested above for about 15 minutes followed by 15 minutes of the highest intensity work planned that day. Now break for maybe five minutes then start the ramp all over again. The players will get far more out of the hard work from two 15-minute segments than from one 30-minute segment. Other important ways to increase intensity: At any running speed, the physiological requirement of running is increased by 10-15% when the athlete is in control of the ball. Therefore, to increase intensity, add a ball because the more opportunities for a player to control the ball, the harder the work. Thus, small-sided games are the best format for this purpose. Weight training When a player wishes to improve strength (a very valuable commodity in modern football), the major portion of the work would be done outside of the competition phase, still following the principles of periodisation. During the season, weight training is continued, but as a maintenance programme, not an improvement programme. Flexibility training Remember that a warm muscle is more receptive to flexibility training. Also, flexibility training should be continued even during the active rest period. Be sure that a warm-up is done before the flexibility work. Flexibility is not a warm-up. Once sweating starts, the body is warm enough to begin flexibility training. Weight loss In-season weight loss is the wrong time of year for weight loss. Using the periodisation model, the competitive time of year is for weight maintenance, not weight loss.

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Considerations for youth There are a number of studies that demonstrate the trainability of children (i.e. under 10 years). In a ball game that requires skill development for some success, many coaches focus on skills. Plus, many leagues allow unlimited substitution, so the emphasis on match fitness is less important. The very young would be losing valuable skill-time should special emphasis be placed on fitness. Some concepts not to be forgotten It is important to stress that no training programme will eliminate the perception of training intensity. The individual perception of a given training load is indeed important. By consequence, if signals of fatigue or over-training appear, the training programme must be individually modified. In particular, high intensity training should not be performed when the coach perceives signals of abnormal fatigue or over-training. Due to the high frequency of games, general fatigue and over-training is a continuous threat to the fitness level of any player. Still, poor performance is sometimes thought to be due to a lack of training. In some cases this perception may indeed be correct, yet in other players the opposite is true. Rest days or low intensity regenerative training sessions often have a much better impact on fitness and performance level than an increased training load. Therefore, if the player feels that they are unable to continue the prescribed training programme due to fatigue, the coach should be contacted. If this is not done, the training programme may actually be detrimental to performance. Some additional things to consider: • Always start each training session with a regular warm-up and end the session with a cooling-down (including the stretching programme). • For those athletes who have a mid-week game, it is very important to do a regenerative training the day after a match and to do a light training session the day

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before the game including a good warmup, mobilisation exercises, stretching and speed exercises. This training session should ideally be done on the pitch that the game is to be played. • When performing high intensity training sessions, the running time should be such that the player can run at a high intensity but still be able to maintain the speed for several exercise periods. The coach should ensure that the exercise intensity during high intensity training sessions does not become so high that the training becomes exclusively speedendurance training. If the intensity is too high, the player will not be able to keep a high enough work rate during subsequent work periods and the desired effect of this high intensity training will be lost. Access to a heart rate monitor is very helpful for determining intensity. • For the same reason, it is essential that the recovery periods are determined according to the different fitness levels. Specifically, for the best runners, a recovery period can be used that is a third of the actual running time. For the intermediate fitness levels, the recovery period should still be less than the running time. Finally, for those athletes whose fitness is poor, the recovery period should be as long, if not longer, than the running time. • Give the players an off-season fitness programme so that they will show up for pre-season training camp at a degree of fitness that they can improve to a higher level and be maintained for a longer time. If players can improve during the off-season each and every year, their basic endurance will be a little better each year and this can make a substantial difference to a player’s career. • Train players as well as possible in the pre-season and try to maintain their preseason level throughout the season. While fitness can be achieved in a short

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pre-season period, the ultimate level of fitness can stay low and can only be maintained for a short period of time. • Try to keep training the youth players harder as the season progresses. In order to do this, one has to plan the season around the fitness plan while ignoring some parts of the game schedule, especially at the beginning of the season. • Competitive games count as a training day, but only for those who actually play. In this regard, equal opportunity should be provided for sports participation. • Training leads to two major adaptations in the body. First is the ability of the cardiovascular system to deliver oxygen to the muscle cells and second is the ability of the muscle cells to use the delivered oxygen. Research shows that the central cardiovascular system’s ability to deliver oxygen to the muscles improves slowly while the muscle cells improve their ability to use the delivered oxygen quickly. When training is stopped, the muscle cells lose most of what they have gained fairly quickly (10 days to two weeks), but the cardiovascular system detrains slowly. Most athletes have probably experienced this when working out after being off for a short break. In this case, the first workout does not feel too bad. During that workout, the cardiovascular system is capable of taking up the slack from the cells that detrained quickly. However, if athletes lay off for a month or more, then they start back from zero in terms of endurance fitness. Career practice pattern, age adequate training - The comcept of deliberate practice It is difficult to watch players such as Luis Figo (of Real Madrid and Portugal), David Beckham (of Real Madrid and England), or Gianfranco Zola (of Chelsea and Italy) and not wonder how these players became so good. How long did it take them to devel-

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op their talent? How many hours did they (and their parents) invest in their careers from the very first time they kicked a ball or played a game of street football? The roles of talent, physical precocity and practice in the development of top players have been studied (Helsen et al. 2000). The goal was to take an objective look at the evidence for practice alone being responsible for the development of outstanding skill levels. Specifically, the “deliberate practice” concept (Ericsson et al. 1993) must be examined in predicting the ultimate levels of expertise in football (i.e., professional, semi-professional, amateur). Deliberate practice is defined as any activity designed to improve the current level of performance that requires effort and is not inherently enjoyable. It is contrasted to other activities that could erroneously be considered practice such as play, work and observing others performing the skill. Their primary prediction is that “the amount of time an individual is engaged in deliberate practice activities will be linearly related to that individual’s acquired performance.” (Ericsson et al. 1993). Most of the research on deliberate practice in sport has focused on individual sports such as wrestling, figure skating, or karate (Starkes et al. 1996). An overview of the findings suggested that for individual athletes there is a linear relationship between amounts of accumulated practice alone and level of performance. This finding supports the model of deliberate practice; practice activities most related to actual performance (such as sparring in wrestling, or the practice of skating) are judged as strenuous and requiring concentration. Unlike Ericsson’s musicians however, athletes also find their most relevant practice activities highly enjoyable. Across these individual sports the average amount of practice per week varies by sport, but is consistently high (on average 26.4 hours/week). The data are also close to Ericsson and colleagues’ best musicians

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who practised approximately 25 hours/ week. Taken together, these findings have shown that the truly elite performers have put in around 10 years and 10,000 hours of practice in their pursuit of excellence. In addition, the top performers usually began their journey very young, i.e. between three and six years of age. Those athletes starting later and who still put in the same amount of time will never equal the performance of those who began young. Ten years and 10,000 hours averages out to 1,000 hours a year. Divided by 50 weeks, gives 20 hours a week, or 3-4 hours a day. Not a full-time job, but obviously not what most kids can give. The professional players spend many hours a day on the field and off in preparation. As kids, Pele, Ronaldo, Zidane and other great players played for hours in the streets and parks and that obviously was beneficial. Recently, the generalisability of the deliberate practice theory in two team sports (e.g. football and field hockey) was studied (Helsen et al. 1998). International, national and provincial football and field hockey players recalled the amount of time they spent in individual and team practice, sport related activities and everyday activities at the start of their career and every three years since. These activities were rated in terms of their relevance for improving performance, effort and concentration required and enjoyment. Biographic information showed that all groups began playing football at age six years and engaged in team practice beginning around age seven years, on average one year after starting. This information also revealed that it took professional players at least 10 years to eventually play for one of the top teams. The finding that it takes at least ten years of practice to attain what is considered an exceptional level of performance (“10 year rule”) has been confirmed in numerous domains (Helsen et al. 1998).

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One way to look at how much athletes practise is to consider the number of hours per week typically practised at varying ages (Fig. 2.1.19). Overall significant differences between each and every skill level were shown from 12 years into career (Int., = 9.2 hr/week; Nat., = 6.9 hr/week; Prov., = 4.1 hr/week). Across years into career, team practice only increased significantly and progressively for the international players from 9 (5.9 hr/week) to 12 (9.2 hr/week) to 15 years (11.5 hr/week). Mean hours per week spent in team practice as a function of the number of years into career Very important career decisions are made around 10 years into career. Nine to twelve years into career (age 19 years) seems to be a career watershed when the international players steeply increase the amount of time spent in team practice. Part of this change relates to the professional development system in football. In future, will the youth player have to decide at an even younger age (e.g. at 16 or less years) to become involved professionally in football? Likewise, when players recognise they will not succeed in advancing to the professional leagues, their practice patterns reflect this reduced expectation. It is also a time when students are entering university

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or the workforce and they may have less time to devote to practice. Accumulated practice hours as a function of the number of years into career Across skill level, at 10 years into career there was a remarkable difference between international players (4587 hr) and provincial players (3306 hr). Overall differences according to each and every skill level were shown from 13 years into career on (Int., =6328 hr; Nat., = 5220 hr; Prov., = 4081 hr). At 18 years into career, international, national and provincial players had accumulated 9332, 7449 and 5079 practice hours respectively (Figure 2.1.20). Regarding the assessment of the practice and everyday activities, the most enjoyable aspects of practice for the football players were team related and included work on technical skills, games and tactics. For everyday activities, players enjoyed watching football and active and non-active leisure. The things they least liked were running, game analysis, reading books, studying and cycling. These findings are consistent across skill levels. When asked what aspects of practice were most relevant to their football performance, the players stated that working with a coach one-on-one, running, game and tactics, technical skill work and adequate sleep were all precursors to good performance. They also ranked the most

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Theoretical Fundamentals of Training

47

effortful/concentration demanding parts of their practice and everyday activities as: running, strength training, working with a coach one-on-one, working on tactics and technical skills and studying. It becomes obvious that the most enjoyable aspects of practice are those that are most relevant to the real game and, demand the most effort and concentration. Weight training and stretching were not rated highly. Practical applications As football players develop, they consequently put in more hours per week in deliberate practice. Research shows that players performing at the highest competitive level peak at about 17 hours of total training per week. In comparison with individual sports this is relatively low (on average 25 hours/week). Perhaps an increase of the absolute amount of practice time per week from an earlier age (e.g. 16 years of age) and throughout a player’s career might be desirable. But, it could be that football is such a physically demanding sport, that there must be a trade-off between the hours spent in physical practice and rest, if only to avoid injury, illness and overtraining. From a coaching standpoint, if one were to speculate on the possible impact of the concept of deliberate practice, several options emerge. If training history is indeed directly related to performance level attained, then one could always recommend that more hours practice might improve performance. In football, long hours are already spent in team practice but as commitment to a professional career deepens, individual practice clearly suffers. Once players become involved professionally and, by consequence, have more time for their ‘job’, high levels of individual training could more readily be maintained. Individual practice sessions on each of the players’ physical, technical, or tactical weak points in future should go hand-in-hand with efficient team practice sessions.

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Theoretical Fundamentals of Training

The relative age effect in youth football competition When children are separated into age groups, there are physical, cognitive and psychological differences between the youngest and the oldest children. The ‘youngest’ children are boys or girls who are born far from the cut-off date while the ‘oldest’ children are born close to the cutoff date. There can be an age difference of one year between the ‘oldest’ and ‘youngest’ participants within any age group, resulting in huge differences in development and maturation. The relative age effect (RAE) refers to the difference in age between individuals in the same age group. In professional sports, it has been shown that asymmetries in birth date distributions are apparent in various professional sports, including American college football, baseball, cricket, ice hockey, football and swimming. Recent studies in youth sport (Helsen et al. 2000) clearly showed the impact of the RAE when, in line with the FIFA guidelines the selection-date changed in 1997 from August 1st to January 1st. With August 1st as the selection-date there was an over-representation of players born in the months of August, September and October. One year after the cut-off date moved to January, the over-representation moved to the months of January, February and March. This clearly shows that the selections are made on the basis of ‘older’ and physically more mature and stronger players (Helsen et al. 2000). Some players that are older and physically well developed, but less talented will therefore be chosen. They only play at a higher level because they are more mature. When all players are mature, the physical advantages of these older players disappears making it difficult for that early mature, but less skilled player to maintain the level they had before, meaning the RAE decreases after maturation. Significant effects have been found for many countries. In Germany, 50.5% of players were born in the first quarter while

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only 4.4% were born in the last quarter. This RAE even extended to youth national teams. There are three main findings. First, there is an RAE that is similar to the one of national youth selections. Second, it is shown that the RAE comes mostly into play from the U13’s onwards, the age at which the physical differences between players of the same age category are most pronounced. Finally, from the results for the U-17’s, it becomes clear there is a drop out effect as there is no longer any player born May to August. As the primary function of a football club in general and an academy in particular, is to guide young players in their development, the consequences of these findings should be taken into account. Selecting players because of their relative physical advantage is not the best long-term option because after maturation this advantage is no longer present and the chances of drop out increase. Unfortunately, physical size seems to be a real pitfall in identifying future elite performers. As a result, a lot of talent is not detected. Players who are less physically developed because of their younger relative age in a category, but who are talented, are clearly not selected to the same extent. These players are denied access to professional training and the opportunity to fulfill their potential. In the long term, this results in a devaluated selection. There seem to be three possible explanations for the relative age effect. First, the physical component mentioned above is the most important factor. To solve maturity mismatches in size, strength and power, changing the rules is an option. As it has been shown in other sports, eliminating physical contact (e.g. tackles, body checks, etc.) clearly reduces the relative age effect and this can also prevent injuries in those players who are ‘less equipped’ to play the game.

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A second explanation for the relative age effect is found in the psychological component. An ‘older’ player will experience more success than a ‘younger’ one because of the physical advantage and this may increase the motivation of older players. Because of this increased motivation, the player will commit more effort to practice. The opposite process might appear in the ‘younger’ players, who, in many cases, may drop out of football entirely. A third factor to explain the relative age effect is the experience component. Players born in January are not only older than players born in December of the same year, but they also are more experienced because they have been able to practice and compete more. For two players with the same physical characteristics, a coach will choose the more experienced (older) one if a choice has to be made. Several possible solutions have been suggested. The first, is to rotate the yearly cut-off date, (Boucher and Mutimer 1994), which gives all players the advantage of being ‘older’ at some point in their football career. A second possible solution is to make more categories with a smaller bandwidth (e.g. one year instead of two). This results in a narrower age range, which reduces the relative age difference within age groups. A third solution stresses the importance of a change in mentality of youth team coaches. (Helsen and Starkes 1999a, b). Coaches should pay greater attention to technical and tactical components when making selections and not only physical components such as height or physical maturity. Therefore, select the most talented players instead of choosing less talented but ‘physically better equipped players’. Finally, the approach of the youth coach needs to be addressed. The statement ‘winning isn’t everything, it’s the only thing’ unfortunately represents the philosophy of many youth coaches. In this ap-

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proach, the ‘youngsters’ of the age group won’t experience success enough and will drop out. That is why a coach has to be task-oriented and focus on development rather than wins and losses; the result of a game should be of minor importance. In the light of information presented here, it seems that players born late in the selection year almost do not exist. Hopefully, Football Associations and club teams will take these recommendations into consideration and provide an equal chance for each and every child to support the idea that ‘learning isn’t everything, it’s the only thing.’

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