Craig Payne

University lecturer, runner, researcher, skeptic, woo basher, clinician

May 30, 2017
Published on:
1 min read

It is always good to see prospective studies on risk factors for injury. Prospective studies carry a lot more weight than cross-sectional studies and require a lot more work on the part of the researchers. This one caught my eye a few months ago, but all sorts of events prevented me getting to it until now:

A prospective comparison of lower extremity kinematics and kinetics between injured and non-injured collegiate cross country runners
Robert I. Dudley, Derek N. Pamukoff, Scott K. Lynn, Robert D. Kersey, Guillermo J. Noffal
Human Movement Science; Volume 52, April 2017, Pages 197–202
Collegiate cross country runners are at risk for running related injuries (RRI) due to high training volume and the potential for aberrant lower extremity biomechanics. However, there is a need for prospective research to determine biomechanical risk factors for RRI. The purpose of this study was to prospectively compare ankle, knee, and hip kinematics and kinetics and ground reaction force characteristics between injured and non-injured cross country runners over a 14-week season. Biomechanical running analyses were conducted on 31 collegiate-cross country runners using a 3-dimensional motion capture system and force plate prior to the start of the season. Twelve runners were injured and 19 remained healthy during the course of the season. Peak external knee adduction moment (KAM), a surrogate for frontal plane knee loading, and peak ankle eversion velocity were greater in runners who sustained an injury compared to those who did not, and no differences were noted in ground reaction force characteristics, or hip kinematics and kinetics. Reducing the KAM and ankle eversion velocity may be an important aspect of preventing RRI.

Nothing jumps out at me as really being problematic. The sample size of 31 is going to a problem for those who do not like the results of the study. For others, we are going to consider many other factors such as the strength of results, effect sizes, etc before considering that being problematic. I rarely dismiss the results of a study based on sample size; instead, focus on the probability that a larger sample size could have or would have changed the results.

Two things did jump out at me from the results of this study:
We have been subjected to a lot of Dunning-Kruger inspired nonsense in recent years on the concept of “overpronation“. This study adds to the actual evidence on the topic, showing that the velocity that the “pronation” occured at was a risk factor for injury. This makes sense, as the faster that it happens, the more loads are going to occur in the tissues as more force will be needed to stop it. This is somewhat similar to the concept of the static test of supination resistance (I just wish someone would do a study comparing the static clinical test to lab based kinetic variables).

Secondly was that the authors found the impact related ground reaction force characteristics were not related to an injury. I hate to think how many times I have harped on about the lack of compelling evidence that links impact related parameters to running injury (here, here and here, etc), yet it still remains the root of all evil in so many narratives.

As always, I go where the evidence takes me until convinced otherwise …. and this study shows that ground reaction force parameters are not related to injury and an “overpronation” related factor is related to injury.

Dudley, R., Pamukoff, D., Lynn, S., Kersey, R., & Noffal, G. (2017). A prospective comparison of lower extremity kinematics and kinetics between injured and non-injured collegiate cross country runners Human Movement Science, 52, 197-202 DOI: 10.1016/j.humov.2017.02.007