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Stride Mechanics - Post 2

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7/17/98

As I said in my previous post, you make some very good points, Jimmy. I just don't think they apply to everyone, especially many of the folks found on the Beginning Forum. And, I do disagree with a couple of your specific opinions.

Firstly, I certainly agree that we should all be striving for a faster stride rate. Especially beginners, who typically have a lot of room for improvement in this area. It is one of the only two ways we have to get faster. And, 180 should be a goal for all of us. Some will reach it. Some won't. Some will get there quickly. Others will take longer. However, it shouldn't be forced at the expense of stride length. I don't think that someone currently running 150 should go out and expect to step it up to 180 instantly. Like any drastic change in running, it should be gradual. And it takes work, not just desire. Fast twitch muscle fibers have to be developed through speed sessions and weight training. Basically, however, stride rate is something that anyone can work on, regardless of his/her level of running. And, as you said, even Glover in his "old stuff" says that stride rate will make you faster. He would be a pretty lousy "authority" if he said otherwise. :)

There is an optimum combination of stride rate and length for any given pace for every runner. You can sometimes run the same pace with less energy expenditure, or run faster with the same energy expenditure, by increasing stride rate and decreasing stride length. (And sometimes vice versa.) As I said in my post, I think this usually means that one is overstriding in the first place. Thus, the adjustment is correcting an existing deficiency and makes one a more efficient runner.

Actually, I think there is also another factor that enters the picture with this adjustment, which we haven't discussed yet. Let's assume that in increasing stride rate from 160 to 180 you maintain the same breathing rate. That's a 12.5% increase in both stride rate and breathing rate. Thus, your oxygen intake increases by that amount per minute/hour/mile/whatever. As long as you are running below your AT, running will be more comfortable at a given pace or faster for a given level of perceived effort. I went through the same experiments shortly after I started running 15 years ago and learned that I could "cruise" easier and/or faster at a certain combination of rate and length than if I adjusted either way from it. That should translate to faster race paces, also.

I don't think I said anything in my post to disagree with you on these points.

However, where I disagree with you is concerning "learning" the ball-heel stride. There are a few people for whom it is natural. They are exceptions. I think it is a mistake for most runners, who are natural heel-ball striders, to attempt to adopt a "learned" ball-heel strike. There are two reasons. One is that it requires more energy per stride than the heel-ball stride, since it is more "explosive." It's true that it has the potential for offering more raw speed. But, since it is a more demanding stride, it can't be sustained for extended distances as well as the heel-ball. Sure, highly developed runners can use it through distances as long as 10k, ala Gebrsellassie and the Kenyans. But, even many, if not most, elites resort to heel-ball for marathons and road races of shorter distances where they aren't running in spikes, as on a track. Most runners aren't speed limited by bio-mechanics anyway. We are more limited by VO2MAX and LT. And, those who develop their LT and VO2MAX to the point that their footstrike becomes the ultimate limiting factor have reached an advanced stage of development and should not hesitate to experiment with footstrike. That ain't most of the folks on this Forum. :-) In other words, I think it's the last thing a runner should try to change in the progression of development. There are many more things to work on before then.

Also, I agree with you that the forefoot inherently has greater shock absorption characteristics than the rigid old heel bone. However, that doesn't translate to a ball-heel stride being more shock absorbing than heel-ball. Let me try to explain that apparent contradiction.

I think there are four natural body shock absorption actions/features.....and they come into play sequentially when running.....the heel, pronation, knee flex and forefoot structure. OK, admittedly the heel structure is not designed for shock absorption. It's only bone with a minimal amount of flesh covering. That's why most people think that heel striking is "pounding". And, it is pounding for a heavy heel striker. However, recognizing that the vast majority to runners are heel strikers, today's running shoes are designed with shock absorption features to augment this area, as well as the rest of the stride, with the use of sophisticated midsole materials and, often, inserts of air or gel. Thus, the shock absorption that occurs at the heel is more due to shoes than bodily structure, although a severe heel strike due to overstriding can still be a problem.

Beyond the shock absorption characteristics of the shoes, most of the shock absorption provided by the body is due to pronation and knee flex, rather than foot structure or foot strike method.....and pronation is limited with a ball-heel strike.

A heel-ball stride permits all four of these shock absorption functions to come into play. A ball-heel stride takes two of them out of the picture (pronation and the heel shock absorption features designed into the shoes) and relies to a much greater extent on just knee flex and the forefoot. Clearly, this is more important to the vast majority of runners who pronate than it is to someone like you is a supinator, Jimmy.

Finally, a ball-heel stride places more stress on the achilles tendons, shins, calves and back than a heel-ball stride does, according to Glover. I find it interesting that only Glover seems to dwell on the relative advantages/disadvantages of foot strikes. All of the others....Daniels, Noakes, Martin and Coe, Higdon....don't really discuss it. However, without exception, as far as I have seen, each illustrates and describes a heel-ball stride when illustrating running form, although Daniels is silent on the subject since his book has a more limited purpose. It's almost as if they simply accept heel striking as a given. Also, several made the point that tampering too much with natural foot strike and stride length can lead to more problems than gains.

Clearly, there is a difference of opinion on which is best. Even among elites. I tend to notice footstrikes in photos of elite runners, because it's something that I've long been interested in. I see a lot more heel strikers than forefoot strikers among road racers at all distances, but it is mixed. A good example is a photo on page 66 of the July issue of RW, which shows the four front runners (two Kenyans, a South African and a Brazillian) in the Boston Marathon at mile 22. Three of the four are about to experience a footstrike. One is clearly a heel strike.....and a fairly hard one it would appear. Another looks like it's probably going to be a heel strike, but could be midfoot. A third looks more like it will be a midfoot strike. The fourth is in the pushoff stage, so there is no way to tell. On page 71 is the women's winner from Ethiopia clearly making a heel strike. They are also all running with their feet low to the ground, i.e., an elitist's version of the shuffle. Contrast that with a photo on page 49 of three finishers in a 1500m and notice the elevation of the runners, who are clearly Power Running. Of course, almost all photos of non-elite runners in the magazine illustrate heel strike. Also, the photos throughout Martin and Coe, Noakes and Daniels books illustrate almost heel strikers almost exclusively.

I really think it's simple. Leave a natural foot strike alone, at least until a very advanced stage of running. For any given pace, find the stride length and rate combination that is most efficient for you. Don't try to manipulate stride rate/length unless you are overstriding. Rely on your progress that results from training, especially speedwork, and racing to increase both stride rate and length. And don't worry if your stride rate isn't quite up to 180 steps/minute.

Jimmy, I think you and I agree more than we disagree on the principles of this discussion. The purpose of my post was not to challenge you. If it sounded that way, I apologize. My only concern was that folks on this Forum who are not ready to experiment with footstrike might rush out and try it.
 
Jim2