By Invitation
A friend asked me to come and hear a local sports physical therapist who's also a professor at a prominent University in Southern California give a presentation on running injury. He laid out his case to a room full of budding therapists, and a couple of coaches. While there was a certain logic to his style of diagnosis and treatment, despite his claim that he was addressing the "root cause" of injury -- weak hip muscles -- he was still only treating symptoms of a bigger problem.
Deceleration
This PT, with an alphabet of academic accomplishment following his name, says that of the 13 common injuries or conditions he routinely treats, 10 of them are the result of "deceleration" issues, and of the remaining three, two are caused by faulty swing through and one is related to toe off. He points out that deceleration -- that's the phase of the stride when the runner first makes contact with the ground, and sinks into its lowest point -- is the danger zone with regard to running injury. This loading phase, which ends at the greatest point of knee bend, he says, results in an excessive impact of two to three times body weight. He says this is best mitigated through the deeper knee flexion and hip flexion of a "proper" heel strike. Yes, heel strike -- the recently-bedeviled practice of about 75 percent of runners, especially those wearing big, bulky running shoes. While the PT would rather leave the "natural" stride of the runner intact -- whatever it may be -- he believes runners should develop a long, reaching, heel-first landing to attenuate impact shock during deceleration.
Weak Hips
He continues, pointing to a number of projected PowerPoint slides and video clips of runners on a treadmill where these runners are apparently collapsing into themselves on every stride. Indeed, feet appear to crash into the running surface, ankles seem to give way under strain of body weight, knees fold inwardly, while hips, capriciously tilting and rotating, send the upper body into compensatory contortions. Runners stepped through individual video frames looked off kilter, like an animated Vlado Milunić/Frank Gehry structure. Every stride appears as another jangling functional catastrophe. Why? Weak hip muscles.
He shows a slide of an injured runner whose hip and leg were aligned with tape, and who reportedly became pain-free. The long-term fix, of course, would be to have the runner train his hip muscles to take over for the taped areas so he could run comfortably under his own control. And who could argue with such a basic level of fitness? Hip muscle strength and stamina provide necessary stability and alignment for any athlete intent on running farther, running faster, or running with less chance of injury! So, training this area is a no-brainer.
Well, the problem remains that most runners can't be bothered to add a warmup and cool-down to their regimen, much less some esoteric gyrations on one leg. They just want to run. But, even if injured runners were motivated enough to complete some four to six months of progressive exercise to fully condition their hips, thus eliminating the so-called "root cause," they're still subject to injury. That's because the real problem remains.
Faulty Form
I myself have benefitted from high levels of conditioning overriding fledgling skills, but I know with certainty that unless correct running form is learned, eventually the undue strains of sloppiness will overrun even the greatest muscular conditioning.
The PT advocates refining running technique, and describes high degrees of knee and hip flexion during the deceleration phase of the stride as the arbiter of good form. This, he believes is how those tremendous loads of running can best be absorbed. He shows still frames from A/B video clips, along with attendant ground force values, and contends that the heel strike and deeper knee and hip bends ideally cushion the runner, whereas the forefoot landing of that same runner leaves her vulnerable to greater impact forces. I don't follow.
Impact
First, those ground reaction forces at maximum knee bend for each example of the runner's eight-minute-per-mile treadmill pace are 1200 N and 1300 N, respectively, for heel strike and forefoot landing. These forces represent roughly 2.25 to 2.45 times her body weight, respectively. While this is almost 20 percent of her body weight, or about 22.5 pounds, the actual difference in loading between 270 pounds and about 294 pounds, respectively, is less than 10 percent. Seemingly significant. But wait. This level of loading, give or take a bit, is the same for any runner -- that's two to three times body weight -- depending on speed.
Nature sorted this out eons ago, and it's normal to running. This loading is simply support, and a reflection of Newton's Third Law -- equal and opposite. What's overlooked, or more accurately obfuscated, is the impact transient produced specifically by heel striking, and to a lesser degree by a forefoot landing ahead of the general center of mass (GCM). So let's consider this.
For instance, in Dan Leiberman's "Running Barefoot: Biomechanics of Foot Strike" video clips, the heel strike example produces -- POW! -- an immediately visible temblor propagating from the abrupt collision that barrels up the leg like a seismic wave, through the hip, and into the back! But, even though the maximum load is about the same, the forefoot landing example reveals a gentler, more gradual compression and expansion of the musculoskeletal spring -- foot, leg, and hip -- which safely harnesses ground forces, stride to stride. Notice, whether heel-striking or landing on the forefoot, ground forces peak in the same place, and in the same way, and at the same time during mid-stance, where the knee is typically at maximum bend. Plus, the impact transient can easily amount to twice the runner's body weight, too -- a far greater magnitude and a far more rapid loading rate than a mere 100 N difference in PT's observed ground forces. That's like adding a single barbell plate atop a pile of weights already resting on your foot versus dropping that whole stack onto your foot all at once.
I'd like to add that, while the natural logic of bare foot structure was left out of the talk, there is no argument that few runners will heel-strike for long without wearing heavily-cushioned shoes. Heel-strike running picks a fight with nature, and nature hits back hard on that small, bony heel. But even those expensive shoes purchased for protection don't actually do their job, rather they mask unpleasant sensations so errant form can continue. And impact remains. Oops.
Apples and Oranges
Another thing that struck me was that the PT offered the two sequential snapshots of each, heel striking and forefoot running at initial ground contact and maximum knee flexion (and its attendant weight bearing), as though they were somehow comparable. Granted, maximum knee bend is an identifiable marker, usually representing mid-stance. But it didn't.
In the forefoot landing, initial ground contact would occur directly beneath the runner's GCM. By the second frame the runner would be leaning well into the next stride, the muscles were unloading, and she was ready to change support. By way of contrast, the heel-strike runner would initially load the foot with a braking force -- the impact transient -- well out ahead of the GCM. By the next frame, the muscles were still being loaded, and the spring was still being compressed. She still had not passed the vertical line of mid-stance, and so could not begin falling forward yet into the next stride. She was still in the previous stride! In fact, if she were to lift her support foot in that freeze frame she'd fall backward because her GCM was behind her support. It would require one, and probably two more frames for the heel-strike runner to finally get into the right position to let go of the ground and change support.
Nevertheless, the physical therapist is crowing on about how much better the runner's form is because her flexed joints are somehow absorbing 100 N of ground reaction force. Clearly he coached her, and he's proud of it. But I'm thinking that the model runner, a woman whose running form I know well, and who's not a habitual heel striker, but whose heel-striking form the PT is celebrating, is actually trying on every stride to overdo pretty much every mistake a runner can make solely for this A/B demonstration. (Indeed, that was the case. I checked.) Differences in perspective can be fascinating.
Separate Ways
Ultimately this physical therapist would rather not make a wholesale change in someone's running form. He's not schooled in that. Plus, people seeking treatment probably want a quick patch-up, rather than a full stride replacement, anyway. He provides both band-aids and exercises, and no doubt has satisfied patients. They will see him often, and for a long time.
On the other hand, I have no interest in adding shims nor splints nor otherwise convoluting techniques to an elemental human activity. I'm not schooled in that. People come to me when they think there is something athletically that they can do better, especially running. They may or may not have been injured before. They may or may not want to improve their performance, per se. But, by working with nature instead of struggling against it it's possible to avoid common injury and performance pitfalls. Since everybody already uses the running "Pose," the "Fall," and the "Pull" -- whether they know it or not -- I just show them how they can dispense with the excess and superfluous extras that somehow get tacked onto our movements, beginning in childhood.
My "therapy" then is brief. It takes about an hour to learn the Pose Method concept and mechanics. From there my athletes have the rest of their lives to refine, master, and perfect their running form, safely and efficiently.
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