Making Waves

摘要

Imagine you're dangling at the end of a rope. If you're an athlete, able to marshal your exceptionally coordinated muscles, you can ascend to a flat haven at the top of the line. Assuming you have superior upper body strength, you could let your legs dangle and use the energy-intensive arm-over-arm technique to pull yourself upward. More likely, you'll get your lower extremities into the act, gripping with your arms, then with your feet and legs, to hoist yourself toward your destination. The latter strategy can be sustained longer because it engages more of your available body power. Once you reach your imaginary summit, you stride off confidently on two legs.