Body Composition Monitoring

In physical fitness, body composition is used to describe the proportions of fat, bone, water and muscle in the human body. Because muscular tissue takes up less space than fat tissue, body composition, as well as mass, determines leanness. Body composition is therefore the proportion of fat and fat-free mass in the body.

A healthy body composition is one that includes a lower percentage of body fat and a higher percentage of fat-free mass, which includes muscle, bones, and organs. Body size and composition is one of the main fitness priorities, important for success in many sports. For many athletes, this is an area that they concentrate on to reach an optimal body shape for their sport.

Research has indicated that appropriate sport specific levels of relative fat and fat-free mass are beneficial to performance in most sports. In gymnastics for example, there is a relatively strong relationship between several anthropometric variables and gymnastic performance, but the associations are not sufficiently high to predict performance scores on an individual basis. Physical attributes necessary for competition success in female gymnasts have significantly changed over the past thirty years. The progressive increase in the difficulty of skills since the 1950's and 60's has increased the physical demands and the acrobatic nature of the sport. Today's elite female gymnasts are small, lean (low percent body fat), and well-muscled which results in a high power-to-weight ratio. Generally, female gymnasts reach their peak power-to-weight ratio prior to puberty and are ready for elite international competition at the minimum age requirement. Female gymnastics is a sport where athletes are required to maintain a low body weight-to-height ratio if they wish to perform at a high level, particularly as they mature into late adolescence and reach their peak performance years.

Taking skinfold measurements is a common method for determining body fat composition. Calipers are used to measure the thickness of the skin in millimeters at a range of sites around the body (usually seven sites). These measurements are then totaled to provide the sum of seven main skinfold sites (tricep, bicep, subscap, supraspinale, abdominal, thigh, calf). Accurate measurement technique is important and Dr Sacha Fulton holds a Level 2 ISAK Anthropometry Accreditation. Because of the increased errors involved, it is usually not appropriate to convert skinfold measures to percentage body fat (%BF) and is best to use the sum of several sites to indicate changes in body composition over time. Below is a table of general guidelines for using the total sum of the seven skinfold sites.

Excellent

Good

Average

Below

Poor

Normal

Male

60 - 80

81 - 90

91 - 110

111 - 150

150+

Female

70 - 90

91 - 100

101 - 120

121 - 150

150+

Athletic

Male

40 - 60

61 - 80

81 - 100

101 - 130

130+

Female

50 - 70

71 - 85

86 - 110

111 - 130

130+

In some cases, athletes want to know their body composition intimately (percentage of body fat, percentage of lean mass and bone mineral density). This is where the information from a DEXA scan allows Sport Scientists to assess body composition to the gold standard and in much greater detail than doing skinfolds alone. The information from a DEXA scan allows us to deduce how much one’s overall body mass is associated with body fat percentage and amount of lean mass (eg. muscle and connective tissue) in kilograms. We can also deduce the amount by which body mass has changed since previous scans and how this change has come about i.e. an increase or decrease in fat mass, lean mass and body fat percentage. DEXA scans also allow us to measure bone mineral density which provides a snapshot of your bone health. Bone mineral density can identify osteoporosis, determine your risk for fractures (broken bones), and measure your response to osteoporosis treatment.

Peak Preparation can measure your body composition and provide you with feedback on how your body composition has changed over time in response to dietary and training practices. We can also provide a snapshot of your bone health by assessing your bone mineral density.