It used to be thought that there were two determining factors on speed: stride frequency and stride length. Research has determined that there is a optimal stride frequency which maximizes speed without leading to dramatic increases in emerging consumption. The optimal stride frequency is 180 to 190 foot strikes per minute. That formula can be seen in the Olympics. Each runner’s foot hits the ground at the same time, just some have longer strides. So, there still are two determining factors in speed; it’s just that one of them is set around an optimal number.
For athletes interested in speed over longer distances: ten-kilometer road race, marathon or mid-distance trail races (12km): leg strength and turnover are less important than a well-developed anaerobic energy system. To train your muscles to tolerate the accumulation of lactic acid, Dr. David Costill (Director of the Human Performance Laboratory at Ball State University in Muncie, Indiana) recommends interval workouts twice a week. Interval training is critical component of a competitive running program irrespective of the distance. Interval training not only elevates your lactic acid threshold, it also recruits slow twitch muscle fibers to "act" like fast twitch as well as train the muscle to fire at the same time. More over, there is a less quantifiable training effect of "feeling faster" and making the mental adjustment of running at faster paces.
While running at slightly faster racing speed you should ‘try to increase your stride length without getting too much bounce and swing your arms for power instead of just balance,’ says Costill. Check your leg extension too. If your foot strikes heel first with knee extended, try planting the foot flatter, making contact at mid sole. “Don’t lock your knee at or before ground contact, since this impedes forward motion,” he says.
Willie Gault, wide receiver for the Chicago Bears, has this advice: ‘Increase your forward lean, lift your knees more, and extend your legs farther. Watch your arms too. Most people swing them across the body instead of forward and backward.’
The bottom line:
- Research seems to indicate increasing your stride length is the variable for sustained increases in speed since increases in stride frequency would lead to quicker muscle fatigue than maintaining the optimal 180-190.
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