... patellofemoral pain syndrome. A misaligned patella results in pain on the front of the knee, ultimately caused by a weak VMO.My initial reaction was along the lines of “Whoa, back that truck up!” For one, if you read a lot of the literature on patellofemoral pain syndrome (PFPS) from informed sources (as I’ve tried to do), you’ll discover there’s much confusion about what indeed does cause PFPS. (Actually, to take a step back, it’s not even clear that this is a meaningful diagnosis in the first place.) So this article’s pat suggestion that your knee pain is caused by a misaligned patella that in turn is caused by a weak VMO is venturing way out on a limb.
For starters, the role of a mistracking kneecap in causing pain may have been oversold. This study (rather small but intriguing) found no relationship between the amount of patellar mistracking and reported knee pain.
Then there’s the problem of strengthening the VMO in isolation. That, by implication, is what someone with a weak VMO in this scenario needs to do. After all, if your problem is maltracking, and you strengthen all the muscles equally, then it seems you would have the same amount of maltracking, only with stronger muscles causing it.
So how do you strengthen the VMO in isolation?
Well, you can’t, as Doug Kelsey has observed a number of times, such as in this passage:
The VMO is one of four muscles which all share the same nerve: the femoral nerve. Muscles contract when nerves tell them to contract. Since the VMO has the same nerve as the other three thigh muscles, it will contract along with the others. You cannot make the VMO contract by itself.Strengthening the VMO to correct a mistracking patella is a typical old school recommendation for treating chronic pain from achy knees. Tease the reasoning apart, bit by bit, and it falls to pieces. Yet the advice lives on in many corners of the Internet.