BODY COMPOSITION ASSESSMENT & COMMON MYTHS Christopher Berger, PhD, ACSM‐HFS, CSCS University of Indianapolis
PRESENTATION OBJECTIVES To discuss modern techniques of body composition assessment and relate those techniques to strength and conditioning professionals To address some of the myths associated with body composition assessment and give you a chance to raise a few more
COMMON BODY COMPOSITION ACRONYMS BIA BMI DXA SEE UWW
Bioelectrical impedance analysis Body mass index Dual‐energy X‐ray absorptiometry Standard error of estimate Underwater weighing
THE ASSESSMENT OF BODY COMPOSITION Chapter 12 of Essentials of Strength Training and Conditioning (3rd edition) Two‐compartment model
THE ASSESSMENT OF BODY COMPOSITION Skinfold measurement is believed to be the most valid and reliable technique generally available to the strength and conditioning professional
THE ASSESSMENT OF BODY COMPOSITION Classification schemes include… … field methods, lab methods … direct, indirect, doubly indirect
THE ASSESSMENT OF BODY COMPOSITION Classification schemes also include… … anthropometry (BMI, circumferences, skinfold) … densitometry (UWW, plethysmography) … other techniques (BIA, DXA)
SOURCE OF ASSESSMENT PROBLEMS? Do you know what you are doing? Have you been doing ___ long enough? Where did you get your instruction? Is your equipment any good? What are you telling your athlete?
5 MYTHS 1. Body composition = physical fitness 2. Body mass index is worthless 3. Bioelectrical impedance analysis is unreliable but we have to use it anyway 4. Dual‐energy X‐ray absorptiometry is our “gold standard” 5. When it comes to prediction equations, any conversion will do
1.BODY COMPOSITION IS THE END‐ALL, BE‐ALL OF PHYSICAL FITNESS What is your ability to perform physical activity? Health‐related Skill‐related Physiologic
1.BODY COMPOSITION IS THE END‐ALL, BE‐ALL OF PHYSICAL FITNESS More than half (51.1%) of health club members join “to lose weight” Source: The IHRSA Trend Report, August 2012
Active obese individuals actually have lower morbidity and mortality than normal weight individuals who are sedentary Source: Blair SN, Brodney S. Med Sci Sports Exerc. 1999 Nov; 31(11 Suppl): S646‐62.
2.BODY MASS INDEX IS WORTHLESS BMI numbers do not take into consideration the amount of muscle mass and bone a person has. BMI is not reliable for non‐European ethnicities. The lower my BMI, the better! Everybody knows that BMI is not accurate.
Probability human body What are the characteristics of the “normal man”? Ancel Keys (1904‐2004) BMI
2.BODY MASS INDEX IS WORTHLESS 2013 NFL #1 draft pick was Eric Fisher (Central Michigan) 306 lbs, 6’7” height BMI = 34.5
2.BODY MASS INDEX IS WORTHLESS What should body fat % be then? Well…
… no established universal standards … indirect methods produce errors … no universal criterion assessment
Athletic MEN, 5‐13% (3‐5% essential) Athletic WOMEN, 12‐22% (8‐12% essential) Source:
ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription (7th ed), 2014, page 304.
Source:
McArdle WD et al. Exercise physiology: Nutrition, energy, and human performance (7th ed). 2010, Figure 29.3, page 765.
3. BIA IS UNRELIABLE SO… LET’S USE IT! First, do not use this device… … after drinking alcohol … after drinking a large amount of water or after meals (1 to 2 hours) … immediately after exercise … immediately after a shower, bath or sauna Why? BIA is sensitive to H2O Source: OMRON Fat Loss Monitor Model HBF‐306C Instruction Manual, 2012.
18.0 Pop quiz! What’s wrong with this picture? 16.0 14.0 12.0 10.0
YOU BIA
8.0
REALITY
6.0 4.0 2.0 0.0 WK 1
WK 2
WK 3
WK 4
WK 5
WK 6
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Source: McArdle WD et al. Exercise physiology: Nutrition, energy, and human performance (7th ed). Philadelphia PA: Lippincott Williams & Wilkins, 2010, Figure 28.14, page 749.
3. BIA IS UNRELIABLE SO… LET’S USE IT! Bodystat® QuadScan 4000 can estimate intra‐, extra‐cellular, total body water (hydration, edema) “Ballpark” basal metabolic rate, body composition
4. DXA IS OUR “GOLD STANDARD” Well… sort of. Lab reference method, provides bone mineral component of multi‐compartment models SEE 2‐3%
4. DXA IS OUR “GOLD STANDARD” Advantages… … fast, convenient … minimally influenced by water fluctuation … bone mineral densities what you do not know Source:
Ackland TR et al. Sports Med. 2012 Mar 1;42(3):227‐49.
4. DXA IS OUR “GOLD STANDARD” Disadvantages… … very small, large, or lean subjects introduce errors higher than the reference subject … some subjects are too tall, wide for the bed … assumes segment tissue consistency (not true!) … manufacturer differences … you (may) have to be certified to use DXA Source:
Ackland TR et al. Sports Med. 2012 Mar 1;42(3):227‐49.
5. WHEN IT COMES TO PREDICTION EQUATIONS, ANY OF ‘EM WILL DO
Source: ACSM’s Guidelines for Exercise Testing and Prescription. (8th ed), 2010, page 69.
5. WHEN IT COMES TO PREDICTION EQUATIONS, ANY OF ‘EM WILL DO Not hardly
From: Athlete (HarperCollins, 2002) and Howard Schatz and Beverly Ornstein, Schatz/Ornstein Studio
Source: ACSM’s Guidelines for Exercise Testing and Prescription. (9th ed), 2014, page 71.
SOME TAKE‐HOME POINTS When you want body composition data, measure body composition. If you are going to assess body composition, spend the money to do it right. Do the numbers look screwy? If so, don’t use ‘em. Be careful about what your athlete does with the data you share.
SUGGESTED READING Harman E, Garhammer J. Administration, scoring, and interpretation of selected tests. In: Baechle TR, Earle RW (Eds). Essentials of Strength Training and Conditioning (3rd ed). Champaign IL: Human Kinetics, 2008, pp 252‐253, 268‐270. Pescatello LS et al (Eds). ACSM’s Guidelines for Exercise Testing and Prescription (9th ed). Baltimore MD: Lippincott Williams & Wilkins, 2014.