Q. Strings and string tensions... Are the any differences in injuries or performance that come from using different strings or having rackets strung at different tensions?
A. It is generally accepted that looser strings (lower tension) give you more power. How much more power? You wouldn't believe it - it's one percent, or so, for a 10 pound change in tension. Does that mean very much? Well, for identical strokes, that 1% of added ball velocity will cause the ball to land 8 inches further out, or 8 inches further from where it would have landed using tighter strings. What does change with looser strings is the dwell time; the time the ball spends on the strings increases. A lot of people feel that gives you better control. There is absolutely no data indicating that looser strings give you better control. And it is generally accepted, anecdotally, that tighter strings give you better control. Is there any data that suggests tighter strings give you better control? There is only one paper showing a plausible reason why tighter strings would give you better control.
As for injuries, when you hit a ball, there is a certain change in the ball's momentum. That change in momentum is caused by an impulse (the amount of force multiplied by the length of time over which the force is applied). If you go to looser strings the dwell time gets longer, and therefore for the same change in ball momentum, the peak force is reduced. If peak force is causing injury, going to looser strings will reduce the peak force. Does peak force cause injury? You probably think it would, but we have no good data on it.
Q. How does string tension impact play? Is it true that I can hit the ball with more power with a higher string tension?
A. Lower tension will give you about 1% more ball speed. This may not seem like much (a ball previously hit at 65 mph would be increased to 65.65 mph) but just that 1% will add about one (1) extra foot to the length of your groundstrokes. If a shot you used to hit landed 1/2 foot inside the baseline, adding 1% to the ball speed will result in the shot sailing long by about half a foot (if all else is held constant).
Q. Is luxilon a better string than gut? Does it have more playability? Is it more powerful?
A. The jury is still out on Luxilon. It seems to be more durable and it may provide just a little bit more spin on the ball.