Fatiguing your way to your injury? Endurance Injuries, Part 2

Yesterday we wrote about the importance of endurance acquisition in preventing injuries. It is not a coincidence that many injuries sneak up on athletes in the later part of a game or event. Fatigue can predispose us to the variables that sent up compensation and injury, not always of course, but often.  

We felt it would be worthy work to look into a few other journal articles to make our case, not that it truly needed to be hammered out further, but we like to hammer.

We discovered that novice runner's (1) trunk inclination increased and ankle eversion increased with fatigue. Furthermore, as fatigue increased, it was noted to be prominent in the hip external rotators and hip abductors (2). We have discussed this ad nauseam over the years. Failure in these areas impact one's ability to hold sufficient limb rotation to ensure clean sagittal knee mechanics.  Challenges in these motions also lead to faults in foot targeting.  When these abductors and external rotators fatigue or weaken, hip adduction can often occur leading to undesirable medial foot targeting, hence narrow step width and our favorite soap box topic, the cross over gait. These issues become pronounced at the end of the run according to the Dierks study. However, in the 2nd Dierks (3) study these findings were challenged, "uninjured runners normally experience small alterations in kinematics when running with typical levels of exertion". Similarly, in the García-Pinillos study, (5) no major form failures were noted in endurance athletes that pushed their limits in another type of failure test, the HIIT (high intensity interval) workout. Dierks (3) remarked that "It remains unknown how higher levels of exertion influence kinematics with joint timing and the association with running injuries, or how populations with running injuries respond to typical levels of exertion.". 

None the less, these are just two studies, and there are others to refute it. We do however, challenge this. But, this is easy to do, because all day long in our clinics we see and hear the cases where there is correlation, because the people seeking us out are in fact "symptomatic" patients and not uninjured runners, so it is easy to lean in one biased direction from our end. Though, it bodes the bigger question off of this following statement, "uninjured runners normally experience small alterations in kinematics when running with typical levels of exertion", as to whether in time, these small alterations might lead to a symptomatic state. One can easily theorize that it is in fact this time variable that eventually leads these small alterations towards bigger ones that might become symptomatic. After all, every avalanche starts with a single snowflake, no offense to the snowflakes out there.

Shawn Allen, the gait guys

References:

1.  J Sci Med Sport. 2014 Jul;17(4):419-24. doi: 10.1016/j.jsams.2013.05.013. Epub 2013 Jun 19.
Kinematic changes during running-induced fatigue and relations with core endurance in novice runners. Koblbauer IF1, van Schooten KS2, Verhagen EA3, van Dieën JH2.

2. J Orthop Sports Phys Ther. 2008 Aug;38(8):448-56. doi: 10.2519/jospt.2008.2490. Epub 2008 Aug 1.
Proximal and distal influences on hip and knee kinematics in runners with patellofemoral pain during a prolonged run. Dierks TA1, Manal KT, Hamill J, Davis IS.

3. J Biomech. 2010 Nov 16;43(15):2993-8. doi: 10.1016/j.jbiomech.2010.07.001. 
The effects of running in an exerted state on lower extremity kinematics and joint timing. Dierks TA1, Davis IS, Hamill J.

4. Gait Posture. 2014;40(1):82-6. doi: 10.1016/j.gaitpost.2014.02.014. Epub 2014 Mar 4. 
Do novice runners have weak hips and bad running form? Schmitz A1, Russo K1, Edwards L1, Noehren B2.

5. J Strength Cond Res. 2016 Oct;30(10):2907-17. Do Running Kinematic Characteristics Change over a Typical HIIT for Endurance Runners?
García-Pinillos F1, Soto-Hermoso VM, Latorre-Román PÁ.