We live in a generation that is generally characterized as underfit and over-fat. Population studies show that 90 percent of Americans do too little exercise to receive any measurable fitness benefit (Centers for Disease Control, 1989). In spite of our national emphasis on fitness and sports, it seems that most people are observers rather than participants.
For example, in a classic study conducted at Tufts University (Campbell 1994) 12 senior subjects were placed on a basic program of strength exercise. They performed about 30 minutes of strength training, three days a week, for 12 weeks. As a result they added three pounds of lean (muscle) weight, and lost four pounds of fat weight. Although their body weight changed by only one pound, they actually made a seven-pound improvement in body composition.
Table 1. Bodyweight and body composition data for male exercisers, categorized by initial percent body fat (N = 383).
Percent Fat Initial Reading
Body Weight Pre (lbs.)
Body Weight Post (lbs.)
Body Weight Change (lbs.)
Percent Fat Change (%)
Fat Weight Pre (lbs.)
Fat Weight Post (lbs.)
Fat Weight Change (lbs.)
Lean Weight Pre (lbs.)
Lean Weight Post (lbs.)
Lean Weight Change (lbs.)
(n = 51)
(n = 139)
(n = 109)
(n = 53)
(n = 31
* Statistically significant change (p<.01)
As illustrated in Figure 1, the men who began the program with higher percent fat scores lost more fat weight and gained more lean weight. As this finding was consistent category by category, it seems that excess fat did not limit the effects of the exercise program. In fact, the results of this study indicate that people with more bodyfat may experience a higher rate of improvement from a basic exercise program than those with less bodyfat.
The participants perform the following exercises in general order of larger to smaller muscle groups:
|Nautilus Machine||Target Muscles|
|Leg Press||Quadriceps, Hamstrings, Gluteals|
|Double Chest||Pectoralis Major|
|Super Pullover||Latissimus Dorsi|
|Low Back||Erector Spinae|
|Neck||Neck Flexors and Extensors|
The exercise intensity is increased gradually by means of a double progressive training system, in which the participant alternately adds repetitions and resistance. For example, a trainee who does a repetition with 50 pounds continues to use this resistance until she performs 12 repetitions. After 12 repetitions are completed, she increases the weightload by five percent to 52.5 pounds. When she performs 12 repetitions with this resistance she increases the weightload to 55 pounds.
Wayne L. Westcott, Ph.D., is fitness research director at the South Shore YMCA in Quincy, MA. and author of the new Nautilus book, Building Strength and Stamina.
Brehm, B. and Keller, B. (1990). Diet and exercise factors that influence weight and fat loss. IDEA Today, 8: 33-46.