Fitness Assessment II Lecture- Body Composition 2024 PDF

I. Discuss the purpose of assessing body composition II. Outline a general body composition assessment protocol I. Present anthropometric assessment measures II. Outline the 2-component model as a foundation for practical body compos...

I. Discuss the purpose of assessing body composition II. Outline a general body composition assessment protocol I. Present anthropometric assessment measures II. Outline the 2-component model as a foundation for practical body composition evaluation methods III. Present a variety of common laboratory- and field-based body composition assessment methods › Also address advantages/disadvantages of each method i. Evaluate health risk ii. Classify % body fat (BF) iii. Assess BC alterations iv. Develop appropriate exercise and/or dietary guidelines v. Estimate healthy and/or competitive BW vi. Monitor growth and maturation 1) Equipment should be calibrated and organized appropriately before use 2) Prepare recording sheets 3) Assessment area should be quiet, private, and at appropriate temp. (21 - 23oC) 4) Complete prescreening tools and measures 5) Complete anthropometric measures (ie. ht, wt, and waist circumference measures) 5) Complete body composition measures (ie. UWW, Bod Pod, DEXA, BIA/BIS, skinfolds) Note: Ask for consent before making contact when client. All measures on right side, carefully palpate and always landmark where appropriate 7) Compare client scores to appropriate normative data for interpretation (ie. what do the results mean?) 8) Provide and Convey results effectively to client › Review results w/ client (ie. what category does your client fall into?) › Discuss interpretation (ie. meaning of results), relative to what health condition(s) your client may be at risk for with poor assessment scores  Link overweight/obesity to various health conditions (ex. Low back pain, CAD, diabetes, etc.)?  May also need to consider impact w/ other assessment results › Counsel to “elements of a healthy lifestyle” (ie. diet and physical activity) and associated benefits  Recognize your client’s current stage of change…target movement to the next stage Used to classify health risk (Heyward & Gibson. 2014):  BMI (kg/m2)…wt and ht › Underwt, normal, overwt, obese (I, II, III)  Waist Circumference (wc) › Measure of visceral fat (provides best indication of overall “health risk” for various conditions such as hypertension, diabetes, CAD, PAD, etc.)  (Waist-to-Height ratio [WHTR]) › Evaluates wc relative to ht using a nomogram chart  (Waist-to-Hip ratio [WHR]) › Indirect measure of lower and upper BF distribution  Body is comprised of water, PRO, minerals, and fat (4 components) Common Models:  6-component (6C)…most accurate  4C…“Ideal”  3C…varies (DEXA)  2C…most common/practical…  Divides body into fat mass (FM) and fat-free mass (FFM) › FFM = all chemicals and tissues including water, muscle, and bone 2C model makes 5 assumptions: 1) Density of FM = 0.901 g/cm3 2) Density of FFM = 1.100 g/cm3 3) Density of various FFM tissues constant within individual 4) Densities of FM and FFM identical for all individuals 5) Individuals differ from “reference body” in FM only, while FFM remains constant (ie. 73.8% water, 19.4% PRO, 6.8% mineral) Note: Accurate as long as 5 assumptions met, BUT…Densities and FFM vary w/ age, gender, ethnicity, level of body fatness, and PA level (Baumgartner et al., 1991; Williams et al., 1993; CSEP, 2005)  Estimates body volume (BV), from which body density (Db) is calculated › Db = body mass/BV  BV based on “Archimede’s Principle” › “The buoyant force acting on an object is equal to the mass of the volume of water that the object displaces” https://players.brightcove.net/901973548001/3f85c2bd-f1a3-4fbd-a874- (Hawes, 1996). 7c9bbd73a1a9_default/index html?videoId=5741548621001  https://players.brightcove.net/901973548001/3f85c2bd-f1a3-4fbd-a8 7c9bbd73a1a9_default/index.html?videoId=5741529900001  “Bod Pod” uses air displacement and pressure-volume relationship to estimate BV… …Pressure changes are used to calculate difference in seating chamber volume when a) empty, relative to b) occupied ADVANTAGES:  HW previous “gold standard” (not Bod Pod) DISADVANTAGES:  Specialized equipment req’d (and experienced technician)  Expensive  Invasive (Bod Pod a little less invasive)  Client compliance (breathing, movement, clothing)  No indication of fat distribution (or health risk) i. Fixed values for FM and FFM assumed (HW, BP) ii. Client failure to: › Liberate trapped air (hair/swimsuit) (HW) › Exhale fully (HW) › Remain motionless (HW, BP) iii. Inaccurate estimate of RV (faulty estimate of trapped gas) (HW) iv. Clothing standardization compliance (HW, BP) v. Inaccurate protocol administration (HW, BP)  Gaining recognition as https://www.youtube.com/watch?v=tZZoI83tv14 “gold standard” method for BC evaluation Considered new “gold standard”  DEXA (3C model) estimates quantities of bone mineral, fat, and bone-free lean tissue  Measures X-ray “weakening”…varies due to density, thickness, and chemical composition of underlying tissue ADVANTAGES: DISADVANTAGES:  Less invasive than  Time (10-20 min) other methods  Still “relatively” new  Less compliance req’d by clients  Experienced technician req’d  Considered new “gold standard”  Very expensive  Standardization of software req’d  Low-level electrical current (50 kHz) passed through body… …impedance to current flow measured…total body water (TBW) estimated…used to predict % BF  Electrolytes in body’s water conduct electrical current… … relative water volume (ie.  FFM) =  resistance (R) to current flow =  TBW est. =  % BF …R  in those w/  BF levels =  TBW =  % BF › Adipose tissue is poor conductor of electrical current i. Electrical current follows path of least resistance through body ii. Body and various segments conform to cylindrical shape  Hydration › Dehydration underestimates FFM by approx. 5.0 kg (Lukaski, 1986)  Measurement 2 - 4 hrs post-meal may over-estimate FFM by 1.5 kg (Deurenberg et al., 1988)  Measurement during/following exercise (; R)?  (Menstrual cycle may  R)  Environment ( temp. =  R)  Body position/movement › 12% error (Lozano et al., 1995)  Assumptions (body shape???; equations???) › Approx. 2.7 – 4.0% standard error (Heyward, 1991) Note: Min. error from electrode placement and technician skill ADVANTAGES: DISADVANTAGES:  Non-invasive  Many sources of error  Fast results  No indication of fat distribution (or health  Inexpensive risk)  Min. technician skill  Traditional – estimates Whole Body (WB) resistance › Wrist/ankle electrode placement › Single Frequency  Lower Body (LB) Devices (foot-foot) or Upper Body (UB) Devices (hand-hand) › 2 points of contact and 2 electrodes › Single, dual, or multi-frequency › Common manufacturers: Tanita, Omron  Bioimpedence Spectroscopy (BIS) (measures UB, LB & WB) › UB and LB points of contact and 4 electrodes › Multi-frequency › Common manufacturers: Biospace, Tanita  8-point system, multi-frequency system › 3 frequencies (5, 50 & 500 kHz) at each of the 5 segments (ie. torso and 4 limbs)  Test duration – 45 seconds  Provides valid and reliable estimations of LBM, FM (Anderson et. al., 2012) and %BF (Miller et. al., 2016) › ”Sources of error” are similar to BIA, but are substantially lower…if strict pre-testing guidelines are followed, results are comparable to DEXA  Advantages/disadvantages are similar to BIA, with disadvantages minimized in use of BIS  Indirect measure of subcutaneous adipose tissue thickness › Recommended to take measures from variety of sites  Variety of protocols › Prediction Equations – Population Specific Vs. General › Pros and Cons? https://www.youtube.com/watch?v=vX5DHCKyk4E&feature=youtu.be 1) Good measure of subcutaneous fat 2) Sum of skinfolds (SOS) can provide estimate of total BF 3) Relationship exists b/w SOS and Db 4) Subcutaneous and internal fat distribution is similar for all individuals within genders 5) Age is independent predictor of Db for both genders Note: Also consider sources of error (Gibson, Wagner & Heyward, 2019 – p. 250) PROS: CONS:  Accurate; reliable  Technician error (great deal of practice req’d to  Fast results approach acceptable level of  Inexpensive accuracy) (Clarke et al., 2013; Freedman et al., 2009; Mei et al., 2007; Willett et al., 2006; Kalmijn et al., 1999)  Predictor of health risk (when w/ BMI and/or WC)  Invasive › May indicate fat distribution 2 choices: i. Population-specific eqns › Derived for use in homogenous populations ii. General eqns › Developed from heterogeneous samples (account for characteristic differences)