On a hot July night in 2011, at age 58 years, I (M.J.B.) lunged for a perfectly hit tennis ball and felt sudden, severe pain in the back of my right thigh. I immediately collapsed and landed in a plume of red clay. Over the next few days, I was able to bear weight with the help of a cane, though I noticed numbness and impressive bruising down the back of my right leg. Obviously, I had injured my hamstring muscles and likely the posterior cutaneous femoral nerve as well. Being inherently conservative and wanting to avoid overmedicalization, I called my primary care physician, who referred me for a physical therapy consultation.