premise: "I did it for my well-being because I felt like my leg was starting to tighten up. Already I had that feeling against Nalbandian a little bit because maybe I'm compensating because of my injury."
  He said "No" whenever asked whether to quit because of the injury, and also he emphasized that "it means very much to me (that I can play). It's also should show a message how much and how important this tournament means to tennis. For me, this is equaling like a Grand Slam."
   What does he think is causing his leg to tighten up?
hypothesis: compensating because of my injury