The weights don't lift themselves. Now is a good time of year to get in the gym and do two things:
1. A six week toning regimen for very healthy muscles. Tennis Specific? Anywhere from 3 - 5 sets, of light weights and anywhere from 12-20 reps. I like to start a weight at 3 sets of 12, then build up to the same weight at 4 sets of 15, then go up in weight.
2. Four week power lifting program. After you get all toned, you can do the same excercises 2 or more sets of 8 reps and really push yourself to make rapid gains. Before the car accident I had, the winter previous I had gained at least 20% stregth in all areas. It definitely made it easier to swing a racket. I love to time this around the holidays, when I am going to be having a lot of big protein meals.
Of course, its always good to make sure you are lifting properly, safely and around those who are also.
At 24hr, a dude leaned a barbell up with 90# on it, then the side with 45# feel and landed on my foot, thought I broke my foot, probably got a little fracture... that was two weeks off!
Be careful people!