Here’s a good summary of specific fitness routines and exercises of several leading pros, including Roger, Serena, Murray and others.
The point is not to suggest or encourage recreational and competitive players to adopt one of these fitness routines. The idea is just to make sure you’re including some kind of regular fitness routine besides just playing tennis.
I especially like Martina’s 12 rules of fitness:
1. Have fun
2. Do not follow a set routine
3. Ensure good form
4. Exercise first thing in the morning
5. Stay consistent
6. Variety is the key
7. Stay focused when exercising
8. Breathe right
9. Set yourself goals, challenge yourself
10. Do something that you can become good at
11. Make a weekly plan
12. Be careful and sensible off season