This was recently posted on Barry's website by Barry's partner Ken:
We’ve debated the issue of the trainability of running mechanics, specifically front side and backside, on several sites. Many times the debate turned into the equivalent of a silent shouting match (which is the best definition I can think of for Internet banter) as both sides presented their best arguments.
The following is based upon a series of responses by Ken Jakalski to those who believe that running mechanics must be trained in order to maximize sprint performance.
Once again, enjoy!
Barry
After the Kivi/Alexander study of '98 regarding A and B drills, coaches acknowledged that Mach drills were not simulators of high speed leg swing mechanics. In addition, many speed authorities have now modified their position on the “pawback” as a mechanic of sprinting.
However, they still believe that properly aligning the vectors for landing requires special technique training. This focus is the result of Ralph Mann’s kinematic studies of the early 80s which pointed out that slower athletes (distance runners) land with the foot farther out in front of their body.
Many believe that the foot landing under the center of mass is a trainable mechanic that can influence speed. The argument: slower guys land farther out in front. Faster guys don't. Hence, to make guys faster, teach them to land under the CM. I don't believe Ralph had presented any protocols by which this landing under the CM could be accomplished via drills or cues.
Many coaches analyze the swing phase in two parts: front side mechanics and backside mechanics.
They perceived a direct relationship between the recovery of the leg and the appropriate landing under the CM. The key to an effective alignment of vectors was to avoid what became known as a circular swing. According to their theory, the heel needs to come up under the butt rather than behind the butt, and the leg must be immediately recovered with the hip flexors becoming active to lift the leg so that the heel never travels behind the midline of the body.
In other words, if the upper leg is vertical to the track, the foot must NOT be recovered near or against the hamstring or behind the butt (hence the term backside mechanics).To them, it was taking too long to recycle effectively so that the foot was unable to land under the CM. A heel landing behind the butt was a wasteful motion that delayed proper recovery of the leg.
Coaches have remained focused on the swing theory because they see it as a very “teachable” mechanic intervention. Hence, we have a vehement defense of the notion that the PATH the recovering leg takes is of critical importance to optimizing front side landing mechanics. Because they believe it is a teachable mechanic, they perceive that anyone displaying a foot lagging behind the butt as lacking proper training.
The 2000 Journal of Applied Physiology study, “Faster top running speeds are achieved with greater ground forces not more rapid leg movements” by Peter G. Weyand, et al, demonstrated that swing mechanics were a non-factor. Case closed.
I always believed that modifications to a 'natural' swing (if indeed possible) would be more wasteful, since it seemed—in effect—to oppose the elastic recovery of the leg. In my opinion, this is an unnatural movement that would increase metabolic cost because it requires active muscle work at a time when most of this should be passive transfers.
Ken Jakalski
Here's what I had to say in return….
Ken…you say:
"The 2000 Journal of Applied Physiology study, “Faster top running speeds are achieved with greater ground forces not more rapid leg movements” Peter G. Weyand, et al, demonstrated that swing mechanics were a non-factor. Case closed."
As far as I know, the article didn't examine the swing phase kinematics in question. How can you make conclusions about something that were not even studied?
The studies that have examined swing phase mechanics (most notably Ralph Mann's ongoing research on the best sprinters in the world) has shown that it does.
When I hear your argument (and Barry's) it sounds like you're making unwarranted conclusions from Peter's research and ignoring the other research to the contrary. Mann has almost 25 years of data on this subject…all saying the same thing. How do we reconcile this issue?
As for the recovery being passive, EMG studies refute this. The hip flexors are VERY active through the swing phase….second in duration only to the adductors (which interesting also act as a hip flexor when the leg moves in to extension as would be seen following toe-off).
