CHAPTER 16 15 OPTIMAL BODY WEIGHT FOR PERFORMANCE

Learning Objectives w Differentiate among body build, body size, and body composition. w Find out what tissues of the body constitute fat-free mass. w Discover how densitometry and several field techniques are used to assess body composition. w Examine the relationship of relative leanness and fatness to performance in sport. (continued)

Learning Objectives w Find out what guidelines best determine an athlete's goal weight. w Learn why athletes should avoid crash dieting or fixating on a weight that is too low. w Find out how much weight an overweight athlete can lose per week to maximize fat loss and minimize fat-free mass loss.

Somatotyping- Body Build, Size, and Composition Somatotyping is the. . . Animation Somatotype w Mesomorph- muscularity w Ectomorph- linearity w Endomorph- Fatness Body size is determined by height and weight. Body composition refers to the chemical composition of the body. w Fat mass w Fat-free mass

Did You Know…? Fat-free mass is composed of all of the body's nonfat tissue including bone, muscle, organs, and connective tissue. Lean body mass includes all fat-free mass along with essential fat. Lean body mass is difficult to measure so the fat mass/fat-free mass model is most often used.

Did You Know…? Body composition is a better indicator of fitness than body size and weight. Being overfat (not necessarily overweight) has a negative impact on athletic performance. Standard height-weight tables do not provide accurate estimates of what an athlete should weigh because they do not take into account the composition of the weight. An athlete can be overweight according to these tables yet have very little body fat.

Desired Body Composition (%) Recommended Body Comp (%) Men Women w Essential Body Fat 1 -5% 3 -8% w Most Athletics 5 -13% 12 -22% w Optimal Health* 10 -25% 18 -30% w Optimal Fitness 12 -18% 16 -25% w Boarderline Obesity 22 -27% 30 -34% w High School Students 10 -20% 15 -25%

Assessing Body Composition w Densitometry (hydrostatic weighing/ bod pod) w Bod Pod -2 -3% w Hydrostatic Weighing – 6% w Skinfold fat thickness – 3 -5% w Bioelectric impedance – 9%? w Infrared interactance/ Magnetic Resonance Imaging w Comparing body fat testing modalities **Error data taken from “Weightology”

Densitometry w Body density = Body mass Body volume w Body mass = measured on a regular scale w Body volume = measured using hydrostatic (underwater) weighing accounting for water density and air trapped in lungs w % body fat = (495 ÷ body density) – 450

UNDERWATER WEIGHING TECHNIQUE

Did You Know…? Inaccuracies in densitometry are due to variation in the density of the fat-free mass from one individual to another. Age, sex, and race affect the density of fat-free mass.

Body Composition and Performance Maximizing fat-free mass w Desirable for strength, power, and muscular endurance w Undesirable for endurance or jumping sports if result is a gain in weight Minimizing relative body fat w Desirable, especially in sports in which the body weight is moved through space w Improves speed, endurance, balance, agility, and jumping ability

Risks With Severe Weight Loss w Dehydration w Chronic fatigue w Disordered eating and eating disorders w Menstrual dysfunction w Bone mineral disorders

Appropriate Weight Guidelines w Maximize performance within the specific sport w Are based on body composition w Emphasize relative body fat rather than total body mass w Use a range of relative fat values that are considered acceptable for the athlete’s age and sex

Achieving Optimal Weight w Combine proper diet with exercise. w Lose no more than 0. 5 to 1. 0 kg (1 to 2 lb) per week. w Reduce caloric intake to 200 to 500 kcal less than daily energy expenditure. w Use moderate resistance and endurance training.