Andrew Weil, MD wrote:
And the reason your legs don't come up as high as some Afrians' is because you have shorter lower legs. There's nothing you can do about that.
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WRONG.
The reason why many African's have a stride where their heel touches their butt as they bring their knee forward is threefold:
A) they are running FAST. Ever see a sprinter who DOESN'T have such a stride?? Ever see a jogger who DOES have such a stride?? What comes first, the chicken (the mechanics) or the egg (the pace) ? Maybe a little of both, but I say the "pace" has more to do with dictating the mechanics, and one's conditioning and flexibility dictates how long one keeps that pace.
When you run fast, you need to bring that trailing leg forward very quick and back to the ground, and the quickest way to do it is by shortening the lever (bringing heel to butt). When Africans jog, do they bring heel to butt?? NO. Because they are going slower. Even when they are running fairly fast, but well within themselves, they don't bring their heel that high. It is inefficient to do so when going slower. Look at El G running a 5k race where the pace slows. He is not brining his heel to his butt on the follow-through. And I guarantee you that when you are running 60 seconds per 400 (maybe for only one or two in a row in your case), you likely bring that trailing leg closer to your butt then you think. BUt when you are running a 15:00 5k, running near 5:00 pace? Of course you are not, it would not be efficient really to do so.
B) The Africans are short. If you are little, but want a decent stride length, you need to have a good hip extension, pushing your leg well behind you before it leaves the ground, and pushing off powerfully. When you do that, and attempt to get that trailing leg back in front of you and back to the ground, you really need to snap it back quickly, and it seems that once again, the most natural and easiest way to do that is by bringing your foot up to your butt on the follow-through. Again, compare El G to Bekele in a 5k. At the same pace, Bekele has his heel closer to his butt than El G. Bekele is quite a bit shorter, and in order to maintain stride length he needs these mechanics. Taller guys, especially at moderate paces, don't need to do that as much. They naturally have longer strides.
C) Flexibility and conditioning. If you have tight hips/hamstrings, you will not get the hip extension you should, you will pull your feet off the ground sooner than you should (shortening you stride), and you will not be able to naturally pull that foot up to your butt (tight hamstrings). Good flexibility makes this easier, and conditioning of course allows one to repeat these powerful strides over and over again, and maintain the fast pace for a long time.
In summary: work on flexibility, work on conditioning, work on stride mechanics of improving hip extension (pushing off from farther behind you, ie, not pulling foot off ground too quickly), and snapping trailing foot up towards butt on follow-through. But if you are running 5:00 pace, there is really no need to mimic that motion entirely. But if you running a mile, and running it under 4:20, then possibly you will find it useful to attempt such mechanics.