Weight Training: Body-fat Measurement Imprecise but Necessary on Some Level; Exercisers’ Degree of Muscularity Affects Planning

Knowledge of bodyfat weight is an important tool, even though the methods of determining it are imprecise (calipers, body-fat-measuring scales).  The situation is more critical when an exerciser has a noticeable portion of his or her bodyweight as body fat rather than muscle.  If  an exerciser has a large portion of their bodyweight as muscle, use of bodyweight as a guide will more likely than not lead to success.

The goal of gym-goers looking to build up their physiques is to add muscular weight. Nutrition plays a role but only if you know whether the caloric intake is contributing mostly to muscle gain or fat gain.

Going by scale weight alone in inaccurate because it does not reveal the muscle-fat proportion of that weight.

For example, there are 2 people who weigh 225 pounds. But one has 25% body fat, and the other has 9% body fat. The physical look of each body will be quite different due to differing amounts of fat-free mass. The person with 9% body fat would be better off using total bodyweight, while the person at 25% body fat may be better off using the fat-free mass as a starting point.

225 lbs-56.25 lbs body fat=168.75 lbs fat-free mass.

225 lbs.-20.25 lbs body fat=204.75 lbs fat-free mass. [This person is likely athletic appearing or a muscle model.]

This example shows that for a lesser-muscled person, some monitoring of body fat is needed and that the role of fat-free mass is important. The ways of getting that information is not perfect. For example, the Tanita scales, which I use along with an Excel spreadsheet, are subject to error based on hydration levels. The scales also specifically advise that its scales’ formula for measuring bodyfat may mismeasure body fat for athletes and bodybuilders (people with a large degree of muscle mass). (One could argue that those with low body fat may not need such close monitoring of body fat except by using a mirror.)