Most athletes are so afraid to lose conditioning that they get very frustrated when they are injured. They can maintain fitness by using a training technique called cross-transference, and so can you. It surprises most people to hear that exercising one leg or arm helps to maintain strength, endurance and power in the other limb. A review of 16 well-controlled scientific studies shows that strength training of the opposite limb strengthens the inactive muscles by about eight percent, equal to about half the increase in strength of the trained side (Journal of Applied Physiology, November, 2006).
We think that cross-transference acts on the brain to strengthen nerves, rather than muscles. Each muscle is made of millions of fibers, and each fiber is stimulated by a single nerve. When you exercise, your brain sends messages along these nerves, telling only about five percent of the nerves to contract at the same time. With training, your brain learns to contract a greater percentage of muscle fibers simultaneously. The more you practice a specific exercise, the greater percentage of your muscle fibers you can contract at the same time, so you can lift heavier weights.
Earlier studies have shown that lowering weights with one arm strengthens the other arm even more than raising a weight. We know that you become stronger by exercising against greater resistance and the heavier the weight that you lift, the greater the gain is strength. A person can lower a heavier weight than he can lift when gravity works with him. Exercising one arm makes the other stronger by teaching the brain to coordinate the muscles in the other arm, and the heavier the weight that you lift with one arm, the more strength you will gain in the other.
Subscribe to my FREE weekly newsletter on fitness, health, and nutrition, and get my Fitness & Sports eBook free!
Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in four specialties, including sports medicine. Read or listen to hundreds of his fitness and health reports - and the FREE Good Food Book - at http://www.DrMirkin.com