In 1993 and again in 1999, Wayne Westcott, fitness research director at the South Shore YMCA in Quincy, Mass., assigned untrained, middle-aged volunteers to one of two regimens. Both groups performed the same round of exercises. Both groups put in the same amount of time, but over periods of eight to 10 weeks, the slow lifters gained 50 percent more strength than the controls. A number of professional sports teams have adopted the drill, and body-builders are discovering that they too can gain by slowing down. The question is whether this is all the exercise a person needs to stay healthy.
Few experts go that far.
Any form of exercise is harmful in excess, they say, but aerobic activity has known cardiovascular benefits. It may turn out that 20 minutes of slow torture is the ultimate prescription for fitness. But until all the evidence is in, moderation is surely the best policy. Push those weights until your limbs quiver. Then strap on your helmet and ride home on your bike.