Originally Posted by HookEmJeff
I would say if you're 3.5 and under...it's probably a lot easier to play tennis for longer.
The higher up the chain you go and the more athletic and physically demanding the points, it's obvious more is asked of your body.
If you started young and are playing the bulk of your tennis on hard courts to boot...I'd say it's NOT really a sport for a lifetime.
Doesn't mean you shouldn't try, though!!!!
In Paul Metzler's book _Advanced_Tennis_ (written in the mid-1960s) he gave advice for playing people who use western grips saying (paraphrasing from memory), "Don't approach the net on anything he can get a good swing at. Whatever your western opponent does, hang in there. He might wilt in the second set, no matter how fiery he is in the first set. Using the western style takes a lot of energy."
My speculations: The western style takes more out of your shoulder because you're swinging hard all of the time (because you can make the ball still go in) and it's harder on your legs because you have to squat down lower to retrieve the slices and because you have to squat down and push up with your legs even on moderate balls to generate heavy topspin. The two-handed backhand harder on all body parts except the elbow. Playing such people is harder on the body because you have to jump/split-step on every shot to retrieve those screamers.
When tennis was described as a sport for a lifetime, it was back in the days when people still used continental and eastern-toward-continental styles. You would delicately stroke the ball, hoping to get close enough to the tiny sweet spot to maintain control, and if a club player could regularly hit three good ground strokes in a row he'd probably win the point due to his opponent's unforced errors, but western-grip players with big rackets can keep the point going indefinitely. Now that correct technique is no longer be competitive, it might be more difficult to continue into middle-age and beyond.