Nurition, Health + Performance Objectives

Objectives
EXSS 2021 Nutrition Health & Performance

1.0 Body Composition
• Why measure body composition? o Overweight vs overfat o Successful athletes:
• Optimize size and muscle mass (productive and ballast)
• Maximiase forca and acceleration
• Minismise energy expenditure o Performance and health care realted to %BF o Training periodisation and peaking
1.1 List commonly used body composition techniques
• Underwater weighing 9two compartment model) o Prediction of % fat from UWW
• Air displacement plethysmography o Bod Pod
• Other models o 3/ 4 compartment models

1.2 Define fat mass, fat free mass and total body density
• FM o Extractable liquid, anhydrous o Density of 0.9007 gcm-3 (at 36C) o Contains no potassium
• FFM o Density of 1.1000 gcm-3 (at 36C) o Water content of 72-73% o [K] 68.1mmol.kg-1
• Body Density (BD) o UWW or hydrodensitometry

1.3 Understand how to calculate body density using the equation of Brozek and Siri
• Brozek:
• BD is then coverted to % body fat (%BF) o %BF = [497.1/ BD] – 451.9 o Eg. A 75kf male has immersed mass of 3kg, RV= 1300ml
• Water temp of 35C (WD= 0.9941gcm-3)
• BD= 75000 (75000 – 3000) – 1300 = 1.0544gcm-3 0.9941 %BF= 497.1 – 451.9 = 19.55% fat 1.05445
• Siri: o %BF = 495 – 450
BD
o Uses 0.9000gcm-3 for fat density (at 37C) o Core temp is 7C but usually lower at reest in a compfratable environment and during UWW at 35C

• Brozek and Siri produce similar results within 1% BF over the range of 1.03- 1.10gcm-3

1.4 Outline differences in the two, three and four compartment models of body composition assessment
• Two compartment models divide the body into two compartments: o Fat Mass (FM) and Fat Free Mass (FFM) o Total Body Water (TBW)
• Isotopic dilution o Total Body Potassium (TBK)
• Gamma radiation emitted by 40K which comprises 0.0118% of all naturally occurring K o Eg. UWW
• Three compartment model o FM o Total Body Water