2 days ago, a co-worker showed me a video on YouTube by Somax sports. The video addressed the running mechanics of several top American Marathoners versus the running mechanics of some of the top East African Marathoners. The mechanical flaws noted in the American runners were; too much bounce ( in one example 4”) which increased vertical distance upward and resultant increased ground impact which together added roughly 3 extra miles for the American runner while compared to an East African runner who had a bounce of roughly 1”, reduced stride angle in the American runner ( 90 degrees) versus 106 degrees for the African runner, which caused over striding in the American runners putting them at risk for knee pain, excessive upper body torque for the American runners which created a crossing pattern for both the arms and legs causing them to continually cross the mid-line of the body placing extra stress on the lower body while minimal upper body torque was noted in the African runners, and an increased toe lift angle in the American runners
( as much as ( 30-35 degrees in some American runners) which, over time, would likely lead to the development of shin splints and/or stress fractures. 0 degree toe lift angle was noted in the African runners.
The authors of the video suggests that in order to remedy too much bounce, reduced stride angle which results in over striding, excessive upper body torque and an increased toe lift angle the runner must have adequate range of motion in the hamstrings (135 degrees), hip flexors (90 degrees) and 60 degrees of hip extension. Their approach is based on the idea that over time, due to training and/or injuries, microfiber adhesions form as a protective mechanism to immobilize injured tissues which over time accumulate making the runner less flexible and stiffer with age.
Although this was obviously a selling point for this organization, I’m wondering if there’s any solid research that supports the ideas presented on the video.