...such as sit ups? I have played tennis before, but now im starting to take lessons again, im nervous about fitness activities such as sit ups , push ups etc because most other sports include those, are sit ups push ups etc part of tennis lessons ?
Depends on coach. You may need to do them for basic workouts. If you're going to join a team, you should be strong enough anyways to do at least 20+ push ups, 30+ situps, and run a mile in less than 8 min.
no, it would probably be more running for your agility and speed so u can get to the ball, dont be worried about strength, think about it, they wudnt want an insanely buff guy to play, buff people get tired too easily, they would want someone lean, and that is probably fast in speed. good luck in tennis =)