Re: patella tendinopathy. Ive been studying Aliza Rudavsky & Jill Cooks recently published article on the management of patella tendinopathy. Ive always been educated when Jill Cook produces articles on tendinopathy and Id encourage yall to read it. And, in it is a discussion of clinical testing (which includes the decline single leg squat). My experience is that is indeed a sensitive test for patella tendinopathy, particularly when the point of pain is specifically at the tendon insertion to the patella. The test is specifically done with an upright trunk throughout, it seems. So, the point of my post today is to counter the use of this as same technique as an exercise. Heres why. The rectus femoris is a bipennate muscle that upon contracting does not have a long excursion (I dont have a reference that highlights the muscle excursion of the human RF, but there have been studies that highlight how pennate muscles in the lower limb in jumping animals have very small muscle length changes and much longer tendon excursions, see Biewener et al (1998) J Exp Biol 201: 1691 for an example. So, assuming a small excursion in human RF given the direction of fibre pennation, i.e. not in the direction of the tendon, the tendon should be tensioned by RF and allowed to elongate like a spring. A vertical trunk in a single leg decline squat means as the knee flexes, the whole MT complex elongates. If the exercise is done with a trunk flexion/pelvic rotation, this allows the MT unit to remain unlengthened, meaning the tendon is isometrically loaded like a spring. See my attached video. Frans Bosch has delivered countless lectures on this concept and always convinces me about the validity of the lower limb muscles acting mostly as spring tensioners in jumping and running, and less as force producers like the parallel fibred glute muscles. Frans talks mostly on top speed running however and concedes that starts are very different - where force production is required. He doesnt talk much about stopping jumping, which is not the same as jumping from a run up or changing direction whilst running which is about change of vectors of the same elasticity. Stopping jumping is where the joint angles tend to cause, in my opinion, the most stress on the patella tendon. Anyway, its a thought in progress about isometrically loading the patella tendon using the single leg decline squat. Thoughts welcome. journalofphysiotherapy/article/S1836-9553(14)00091-5/abstract
Posted on: Thu, 21 Aug 2014 09:08:44 +0000
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