What do we “know”about running injuries: Part II
In part one we discussed the kinetics or forces at play during running. Here we will discuss the kinematics or joint angles and positions influencing running injury. The beliefs and theories surrounding reduction of running injuries are limitless. Many have reached a sort of religious or tribal status. A lot of these have had their moment in the sun and then faded away.
Running has many different flavors of “normal”. The flavors of a theoretical optimal are more scant but variation still certainly exists. Among these flavors there are certainly common ingredients.
Cadence
Strike close to COM
Decreased vertical oscillation
These variables directly influence the way in which we interface with the ground, thus directly affecting the amplitude and magnitude of the forces on the body. Each of these variables has been shown to reduce the loading rate and decrease braking impulse, which as discussed in part I appears to be the most important factor in injury risk.
Conveniently, manipulating one often has an affect on the other two. For instance, increasing cadence 5-10% will likely shorted your step length which should shift your strike closer to under the center of mass and thus reduce breaking impulse and vertical oscillation.
As mentioned, there are many flavors of normal. These qualities live on a spectrum with the center being a theoretical biomechanics optimum. Based on a number of constraints (age, weight, anthropometrics) you or your client will not live in the center of the optimal. If performance is plateauing or injuries persistently limit training abilities, perhaps consider increasing one of these ingredients in your recipe for a time. Stir it in and adjust based on taste. Pushing yourself an iteration or two closer to this “optimal” may have compounding effects.
But of course, it’s not that simple. In part III, we will discuss the risk cycle and complex interplay of factors.
Dr. Anthony Iannarino 