I was talking with a customer at Marathon Sports the other day. He wanted to run faster and was looking for a pair of shoes to enable that. Not an unusual topic – who doesn’t want better race times! This conversation reminded me of three interrelated things that directly affect our speed: range of motion; turnover; and push-off. First, range of motion or ROM. Jack Daniels observed that 1984 Olympic women distance runners had a heel-to-heel stride length of 58” and men 74”. This is probably the top end for most of us – but for purposes here let’s assume an average stride length of 59 inches, or roughly 1.5 meters. For a 5K race, that is about 3,300 strides. If a runner’s full ROM is reduced by just 1”, in essence that means running an extra 90 yards. At a 7:00 minute pace this would add 22 seconds. So instead of 21:46 5K, it would take 22:08. For a 10K, double that difference to 44 seconds. And for a half marathon, 92 seconds or 1.5 minutes. Clearly, a price is paid for a constrained ROM. Second, turnover, or cadence as the cyclists call it, is another key part of … Continue reading