When the Nebraska Wesleyan researchers compared the runners’ sit-and-reach scores to the measurements of their economy, which had been garnered from a treadmill test, they found that, across the board, the tightest runners were the most economical. This was true throughout the groups and within the genders. The inflexible men were more economical than the women, and for both men and women, those with the tightest hamstrings had the best running economy. They also typically had the fastest 10-kilometer race times. Probably, the researchers concluded, tighter muscles allow “for greater elastic energy storage and use” during each stride.
In fact, the latest science suggests that extremely loose muscles and tendons are generally unnecessary (unless you aspire to join a gymnastics squad), may be undesirable and are, for the most part, unachievable, anyway. “To a large degree, flexibility is genetic,” says Dr. Malachy McHugh, the director of research for the Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital in New York and an expert on flexibility. You’re born stretchy or not.
“Flexibility is a functional thing,” Knudson says. “You only need enough range of motion in your joints to avoid injury. More is not necessarily better.” For runners, extremely tight hamstrings and joints have been found in some studies (but not all studies) to contribute to overuse injuries. But somewhat tight hamstrings, as the Nebraska Wesleyan study showed, can make you more economical.
Wednesday, November 25, 2009
Stretching (and Flexibility) Update II
This from the NYT: