Last week we ran an archived piece named, “Just because a muscle tests weak doesn’t mean it  needs to be activated”.  Here is the link to that piece.

Today we present some more proof behind our stance on this topic. The referenced article below states in its Context: “An arthrogenic muscle response (AMR) of the soleus and peroneal muscles has been previously demonstrated in individuals with chronic ankle instability (CAI), but the presence of AMR in muscles acting on joints proximal to unstable ankles has not been previously explored.”

And here was their study’s conclusion: “Arthrogenic inhibition of the hamstrings muscles bilaterally and facilitation of the quadriceps muscle ipsilateral to the involved limb were noted in subjects with unilateral CAI. Motoneuron pool excitability appears to be altered in muscles that act on joints proximal to the ankle in those with unilateral CAI.”

This proves our thoughts on a deeper level.  Just because a muscle tests weak does not mean that this muscle is weak or “inactive” or needs  to be “activated”. It is a shame it is not as simple as finding something weak and “activating” it. As we eluded to, this is a far more complex system than that, there are complex feed forward and feedback loops that are mandated and regulated by local cord reflexes, pattern generators and complex cortical loops.  Putting a muscle “back on the grid” prior to activity merely because it tested weak may be putting your client at risk if you are not getting down to the bottom of the problem.  Taking the study mentioned here to a deeper level, finding out that your client has a weak hamstring or quad and negating the possible source of the problem down in an ankle could be devastating to an athlete if they are suddenly returned to aggressive activity immediately after being “activated”.  You may be over riding the central pattern generators, reflex responses and complex cortical loops arthrogenic responses, which could be neuro-protectively calculated. As this article mentioned, “motoneuron pool excitability appears to be altered in muscles that act on joints proximal to the ankle in those with unilateral CAI”.  This is a massively diffuse process going on constantly throughout the body, providing safe mobility and stability. It is not a random process and should not be intervened therapeutically on a random level. At the very least, it requires a patient history, clinical examination, gait evaluation and movement pattern assessment. Anything less is, well, your responsibility if poop hits the fan when they step on the field. 

Shawn and Ivo


J Athl Train. 2007 Jul-Sep; 42(3): 355–360.PMCID: PMC1978472Arthrogenic Muscle Response of the Quadriceps and Hamstrings With Chronic Ankle InstabilityEdward J Sedory, MEd, ATC, EMT,Eric D McVey, MEd, ATC,Kevin M Cross, MEd, ATC, PT,Christopher D Ingersoll, PhD, ATC, FACSM, and Jay Hertel, PhD, ATC, FACSM