Originally Posted by Marius_Hancu
I'd suggest to use your winters mainly for conditioning (say playing not more than once a week), and summers for tennis. You need to establish a good base. It's a good balance.
Perhaps you're playing too much throughout the year.
Also, perhaps 3 times a week is too much for you (I have no idea how frequently you're playing). Reduce that to your own level of comfort.
Also, how's your weight? If too much, than the stress on your joints may be severely increased.
In terms of grip: RELAX it. Too much grip, and all the shocks are transferred to your arms, shoulders, etc. Think of having a feather in your hand. Hold it with 3 fingers to relax the grip. Let the racquet inertia work for you. You may be straining too much your body, by fighting the ball and the racquet. Have a nice, well-timed, impact.
Move more on your toes. You may bumping the ground (and your joints) too hard, if your weight is placed on your heels.
I agree with all of this. Taking some time off (for me from November to March) and focusing on conditioning really seems to help, both with letting the nagging injury stuff heal, but also to get strong enough that I can take a less is more approach and not have the feeling that I'm not doing enough.