If you do play racquet sports, such as tennis, squash, etc. it more than likely will affect your TMJ. When playing any sport which strains muscle groups on one side of the body, it tends to have a negative effect. Golf is another sport that comes to mind that has this same effect. More times than not, based upon your frequency of playing, you can develop a dominant side of the body. I was a heavy racquetball players for years and actually ended up building up the muscles on the right side of my body to the point that you could tell a visible difference. Take a close look in the mirror and see if you can see & feel a strong noticable difference between each side of your body. Pay close attention to the back, shoulder, neck, biceps, and triceps. I had strengthened one side so much that it took physical therapy for me to regain a balance. As a result of the one sideness, I was pulling my spine to the dominant side which in turn was pulling on my face and neck and as a result, was affecting my TMJ. That was a mouthful! Bottomline, if you do any physical training that is dominant one sided, try strengthening the other side and chances are you will be able to tell a big difference right away in your overall well being and TMJ related pain. Good Luck!