In that sense, practice does make perfect.
Since then, Testa has tracked the phenomenon in athletes of all levels and many sports. The more complicated the sport's techniques, he finds, the more efficiency you can gain. "Someone who doesn't swim, for example, will be very inefficient if he falls in the water," says Testa. "He will very likely use every muscle in his body just to stay afloat. After a few swim lessons, however, he'll be much more controlled and efficient, using only the muscles that serve his purpose, without even thinking about it."
Cycling is less complicated than swimming, but more complicated than, say, walking. When you bicycle, muscles in your legs, abdomen and chest contract and relax in a synchronized way. Your quads contract to push the pedal down while your hamstrings relax. Your brain orchestrates this by sending a signal along a nerve to your muscles, causing them to fire in the right sequence. Relax, contract, relax, contract. On, off, on, off. It sounds simple, but this simultaneous contract-relax sequence is neurologically quite complicated. Without practice (and below the level of consciousness), your muscles can be out of sync. Your quads may contract and push down the pedal before your hamstrings relax, resulting in what Testa calls "internal biomechanical resistance."
As you add to your lifetime totals of riding, walking, running, swimming, dancing and so on, a stronger and more streamlined connection develops between your brain and your muscles. The muscle and the nerve that serves that muscle work as a team called a motor unit. With repetition, your brain learns to recruit (or call on) the right motor unit, depending on the muscular contraction you need. The brain also recruits more motor units. More circuits and more connections smooth and strengthen the delivery of information. Your muscles contract and relax more precisely and work against one another less often, thus every mile, stride and lap you do reduces those internal biomechanical resistances. At a certain point, your body will top out on its ability to improve its utilization of oxygen, but improvement will continue because exercise economy will allow you to perform the motion using less energy.
The payoff of repetition is cumulative, adding up over the course of your entire lifetime. To increase your biomechanical efficiency more rapidly, you can try sport-specific drills designed for that purpose. But better efficiency will happen on its own, just by performing your favorite activities repeatedly.
( Eric Heiden, M.D., a five-time Olympic gold medalist speed skater, is now an orthopedic surgeon in Utah. He co-authored "Faster, Better, Stronger: Your Fitness Bible" (HarperCollins) with exercise performance physician Max Testa, M.D., and DeAnne Musolf. Visit www.fasterbetterstronger.com.)