Putting a little knowledge of human anatomy and physiology to practical use...
I wasn't going to post anything to the site today, but I had an epiphany toward the end of practice. Not an Epiphany, just an epiphany. I'm pretty sure that if I'd seen God, I wouldn't be around to talk about it now. But, I do think I see the grand design of things a little more clearly than I did two hours ago.
On recovery days in practice, the TCA distance group typically does four to six strides (or "striders," if you prefer) at the end of practice. I use this time to emphasize the importance of good form and nitpick some at the little inefficiencies of form that I detect. We start our strides at 3200 race pace, move up to 1600 race pace, and generally finish with one or two at 800 race pace. It's all about feeling good at speed and increasing economy of effort.
Today, my fine point of running form to emphasize was keeping the shoulders perpendicular to the line of motion--no twisting and turning of the shoulders. Like I've heard myself and a thousand other coaches say untold times before, I urged the kids to use their arms to counterbalance the movement of their legs rather than twisting through the shoulders. After all, a twisted torso has to return to a neutral position before the next stride and all of that twisting and untwisting is so much wasted energy, motion, and effort. As I finished urging the 25 or so young men and women looking back at me to counterbalance with their arms rather than their shoulders and torso, I added, "This is more difficult for you girls than it is for the boys."
As happens altogether too often, I think about why I said something after it came out of my mouth rather than before. But, I had ample time to think about it as I started each group on their next stride and watched them pass by. For the very first time in 11 years of coaching distance runners, I seriously asked myself the question, "So, why is it harder for girls to run without twisting in the torso than it is for boys?"
The answer--or at least a partial answer--was not long in coming. All I needed to do was think about the human male and female silhouettes on the poster in my high school biology classroom. Males have wide shoulders--specifically, a male's shoulders are wider than his hips. Females have narrow shoulders--specifically, a female's shoulders are narrower than her hips (or at least closer to the width of her hips than a male's shoulders are).
Whether male or female, a runner must counterbalance the movement of the legs with a synchronous movement somewhere in the upper body. For boys, it's relatively easy. Swing an arm in opposition to the leg and, presto!--counter-balancing motion. Even though the arm is lighter than the leg, it naturally hangs wider than the leg and so readily counterbalances the movement of the opposite leg. That may be the simplest concept in physics--anyone who ever sat on a teeter-totter understands that leverage is greater the farther from the middle that you go.
Now think about the same necessity of counterbalancing the movement of the opposite legs in girls. Since the shoulders are narrower relative to the hips, a girl's arm does not have the same counter-balancing leverage as the boy's arm. So, what does the grand design of things instinctively suggest that a girl do to compensate? Carry her arms wider, of course! But, guess what?! Carrying her arms wider (or, alternatively, swinging her arms faster and further forward) requires more energy than is required of a boy to counterbalance the movement of his legs.
You can sense the light in the room getting brighter already, no?
I just decided I'm going to be a lot more kind to the girls on our team about arm carriage.
So, if it's all anatomy and concepts of basic physics, is everything about arm carriage predetermined and set in concrete? Well, I think that's an unnecessary conclusion. Stay with me just a little while longer...
Without naming names, I can think of several girls in our distance group who have "improved" their arm carriage in their years in the TCA distance program. That is they don't carry their elbows as wide as they used to and, more importantly (I think), they don't start twisting in the torso nearly as soon in a race as they once did. And, I don't think it's simply because they've grown weary of listening to me fuss about it.
Just as twisting of the upper torso increases late in the race with enhanced intensity of pace and mounting fatigue, so also does enhanced strength in the shoulders allow a girl to use her arms longer and more effectively to counterbalance the movement of her legs while running. So, a significant part of what all those accumulated miles accomplish is to give a girl the capability of using her arms longer and more effectively before reverting to inefficient torso twisting. Just as accumulated miles add strength to the legs and the heart, so also do they add strength to the shoulders. And, intuitively, added strength in the shoulders is much more important to a female runner than a male runner. But your average girl will never achieve the same leverage from parallel swings of her arm that her male counterpart does.
In fact, if we have a girl consciously bring her elbows in before her shoulders have the strength and endurance necessary to do that under racing conditions, the net effect is likely to bring her nearer to the point where shoulder fatigue produces twisting and turning of the torso! Somehow, I think we male coaches (and perhaps some female coaches as well) have it in our heads that male running form is the ideal running form. But, it may turn out that forcing male patterns of arm carriage on girls, and especially so as they are developing runners, makes them less efficient rather than more.
In time, a well-trained female runner with well-developed shoulder strength and endurance will start to carry her arms more like her male counterparts when she races, but she is not constructed to attain maximum economy with the same pattern of arm carriage that a male runner is. Girls will never achieve the same counterbalancing effect with the same effort in arm carriage as boys do. Either that or the relationship between shoulder and hip width is irrelevant to running form.
That said, at the point where the arms come in close to the chest (and this would be true for boys or girls), there is essentially zero counterbalancing available anywhere except through torso twisting. Fatigue is the only thing I can think of that would cause a person to bring his or her arms in close to the chest (but I don't understand why fatigue would draw the arms in close to the chest unless it's all tied somehow to the instinctive security of the fetal position). And once the arms come in tight all running economy has left the premises. At that point, there is nothing left but a painful, inefficient grind to the end of the race.
With that, I'll step off the soapbox and close out my oratory. I'm very interested in your thoughts. I hope a worthwhile exchange of ideas on the forum trails this article.