Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.A second item concerns exercise and longevity. Larocca et al. show that exercise delays the normal shortening of telomeres that occurs on aging. (Telomeres are tiny caps on the end of DNA strands, long strands of DNA that are snipped when cells divide, a process that is believed to protect the rest of the DNA but leaves an increasingly abbreviated telomere. Eventually, if a cell’s telomeres become too short, the cell either dies or enters a kind of suspended state.)
Tuesday, February 02, 2010
Exercise keeps your cells young, and a tip on running.
Two random items on exercise. Work by Lieberman et al. on running has caused quite a stir in the press (and two MindBlog readers have pointed it out to me). I've tried taking off my running shoes for a few days now, and wow.... this is good stuff. (This should not have surprised me of course...I ran around barefoot for years as a kid growing up in Austin, Texas.) Here's the abstract: