With all the talk about running form, we usually tend to focus on things from the ground up - feet, ankles, knees, hips, back, and keeping everything in proper alignment while we're in motion. One thing we seem to overlook is the shoulders and how they affect our form's alignment from the top-down. As I have been so painfully been enlightened of lately... About 2 months ago I was diagnosed with Tendinosis in the Long Head of the Bicep on my right arm/shoulder. This is the tendon that goes from the muscle, straight up and over the top of your upper-arm bone and connects into the shoulder joint. Any forward/back motion of your elbow as well as any up/down motions of your forearm all rely on this tendon. You're probably wincing as you think about all those motions we do that rely on that one tendon... At this point, I'm basically unable to run (or do many other things that rely on that arm), as the forward/back motion that good/proper form requires makes it even more painful and the natural tendency is to rotate the entire shoulder to compensate. This has the negative affect of moving to the "cross-body arm swing", throwing my alignment off and adding stress to everything all down my right side, even to the point where it causes me to rotate slightly on the ball of my foot (and the associated blistering *that* causes...). So, not only is this painful in my shoulder, but trying to spend any time running is quickly aggravating old piriformis, SI, and IT Band injuries and causing stress in my knee on that side because of the bad form it encourages.... So - one tendon, on the opposite end of the chain, seriously disrupting the entire thing. Bit of an eye opener for me about how truly interconnected and inter-related everything in the machines we call our bodies really are.