In most sports, technique and performance are closely linked. Take golf, for example: Golfers derive power from their hips, so hip engagement and rotation are pretty well correlated with how far and accurately a golfer can drive a ball. Running is different. How fast somebody runs is mostly about bioenergetics—the internal stuff, like the strength of the heart and efficiency of the muscles—not biomechanics, which is how individual body parts move together. If you wanted to go fast, you were better off lining up for intervals, not perfecting your arm swing.
Recently, however, the hands-off approach to running form has been called into question throughout the sport, from scientists like Larson and Harvard’s Daniel Lieberman to elite coaches like Alberto Salazar. Meanwhile, chatter on the topic fills running forums and blogs. Form, it seems, suddenly matters.
It’s long, but definitely worth reading.