Running Changes. . . Should you Shorten your Stride or Run Barefoot?
We’ve read a lot about barefoot running lately in the popular press, in research studies and in this newsletter (in fact, David has lectured to a number of groups about this, including Creighton University Physical Therapy Department and the Omaha Running Club). Much of the research is showing a decrease in overall injury rates. Why is this happening though? David attended a meeting last year in San Diego during which a colleague from the University of Wisconsin at Madison discussed a very cool study they just performed. Running at the same speed, but with a faster cadence resulted in a shorter stride length which decreased knee stress, hip motions and overall braking forces. Might this be why barefoot running is so beneficial?
Many of us have heard the mantra to avoid overstriding. But why? When runners take strides (steps) longer than ideal, a very sudden increase in ground reaction force (basically an impulse, for all you biomechanists out there) occurs followed by a short decrease, followed by another increase in ground reaction force. An overall ground reaction force is necessary if running is the desired activity, but that initial impulse actually results in a braking or slowing action on the body.
That’s where barefoot running comes in. Barefoot running decreases a runner’s stride length (probably because it would hurt the heel too much with a longer stride), thereby eliminating that initial increase in force (impulse) and therefore eliminating that initial braking action.
So, the researchers in Wisconsin did something interesting. They had runners maintain their normal, self-selected pace, but increased their cadence. That is, they had them take more steps per minute than normal. Specifically, they increased the cadence either 5% or 10% more than normal. So what happened?
- As the cadence increased, the stride length decreased.
- As stride length decreased, the runners bounced less and produced lower braking forces against the ground.
- A shorter stride allowed the knee (and hip) to do less work absorbing energy.
- A shorter stride allowed the knee to bend less during stance, and decreased many hip motions.
So, interesting information . . . but what does it mean? There’s a lot of information on barefoot running (and its very real benefits), but is there a better way? It appears that many of the previously cited barefoot running benefits are actually accomplished by running with shorter strides. Is that, then, a better approach? It’s difficult to say at this point, but that would be my inclination.
I am quite certain, however, that discussion of this topic is not over, we will hear more. And as it comes out, I will be sure to update you.