Well...I Found this good site that tells me how to get fit, and condition for tennis. And also, if I wanted to, get bigger. I'm sure all of these workouts on the site are legit and good, but I don't understand what sets and reps are. Could anyone help? If it says do 5 sets of 5 reps. What does that mean? What are sets? What are reps? THanks for all the help.