Body composition and body weight are two of the many factors that contribute to optimal exercise performance. Taken together, these two factors may affect an athlete’s potential for success in a given sport. Body weight can influence an athlete’s speed, endurance, and power, whereas body composition can affect an athlete’s strength, agility, and appearance. A lean body, for example one with a greater muscle/fat ratio, is often advantageous in sports where speed is involved.

Finding the right balance between weight, fat and muscle is important to monitor over time to ensure peak performance is achieved. In general, having a relatively low body fat percentage may aid athletic performance by improving the strength-to-weight ratio. It also helps by lowering the resistance, or drag, an athlete has as he or she runs etc. Having too little body fat on the other hand can be dangerous as it is an essential energy store which is particularly important for race training and endurance sports.

Evaluating body fat at home

An athlete’s body fat percentage varies depending on the gender of the athlete and the sport. Optimal body fat percentages for an athlete should be determined on an individual basis. Because the amount of body fat, not the weight, is the important factor in living a healthy life, it is better to determine and track the percentage of your body weight that is body fat (percent body fat).

The traditional method of measuring body fat is with skinfold calipers. If each test is performed correctly, according to the recommended guidelines, there is a +/- 3% error. As the calipers measure subcutaneous fat (under the skin) the accuracy level reduces if the person is very lean or obese. The method is inexpensive and fast with an instant reading.

New technology has driven the development of new fitness devices that use bio-electrical impedance analysis (BIA) to measure body composition. They are very much like a traditional bathroom weighing scale but with built in BIA electrodes which will scan the body and measure your Body Fat, Muscle and Total Body Water levels in addition to other fitness markers such as visceral (abdominal) fat, basal metabolic rate and bone mass.

For in-depth analysis of how training affects body composition, the Tanita BC601 Segmental Body Composition Monitor measures each arm, leg and trunk area separately and stores the data on an SD card. The measurements can then be downloaded and monitored. This is especially useful for assessing the effectiveness of a new training program or monitoring injury recovery.

“Excess body fat in sport is generally not conducive to optimal training and performance, and we at Tanita understand the need to measure body fat as well as muscle mass changes in the body on a regular basis to maintain optimal health and performance,” says Simon Bradeley, Body Composition Expert, Tanita Europe. “We can now provide measurements such as total body water and basal metabolic rate to give the user greater understanding of what changes are taking place when you exercise and make dietary changes in your life. Before, it has been costly and intrusive to make these measurement but we think it’s important to be able to measure quickly and cost effectively at home.” 

So whether you are using basic calipers or the latest BIA technology, carefully monitoring changes body fat levels along with hydration during intense training and pre-race conditions is essential to achieving optimal performance and reducing the risk of serious injury.