STRENGTH TRAINING IMPROVES ENDURANCE

Report #6587 8/21/95

Training is supposed to be specific. If you want to become strong, lift heavy weights. If you want to develop greater endurance, exercise for a long time. However, a study by Ben Hurley, of the University of Maryland, has shown that strength training can increase your endurance.

Runners started a strength training program with weights. After 12 weeks, their quad muscles, in the front of their upper legs, were 52% stronger, while their hamstrings, in the back, increased by 30%. That's what you would expect, but the surprising finding was that they were able to increase their maximal endurance on a bicycle from 26 to 35 minutes.

Muscles are made up of thousands of individual fibers. When muscle fibers become larger and stronger, fewer fibers are required to exert the same force. So, fewer fibers are required to do the job and more can rest. The extra rest increases endurance.

Does this mean that you have to lift weights to be a competitive distance runner? Of course not. Your muscles contract against greater resistance when you run faster, because your feet push against the ground with greater force. Other studies show that running very fast once or twice a week will also increase endurance. Beware, lifting heavy weights with your legs at the same time period that you are trying to run many miles/ increases your chances of injuring yourself.

By Gabe Mirkin, M.D., for CBS Radio News