My junior tennis lessons run anywhere from 30 to 60 minutes. I focus on skill development and match play. I don't have a lot of extra time for warm-up or fitness activities. After spending the last year cranking out hundreds of lesson plans, I had a light bulb moment. I remembered my son's club soccer team had a warm-up routine they did at every practice. The coach had developed a simple but effective routine that got everyone warmed up, and, even better, required no adult supervision - the team could run through the routine on their own. So I did the same thing for my Orange Ball and up classes. Happy to say it is working great. One of my proudest moments was coming to the court behind the kids and watching them line up on the baseline and start their warm-up without me saying a word (sniff, sniff, shedding a tear). Seriously, this way they can warm themselves up when playing for fun or prior to match play when I am not around.
Here's what I included in my 8 point warm-up. Yours doesn't have to be 8 points. It doesn't have to included these specific exercises. The point is to have something that works well for your students and your lesson time.
1 Medium jog
2 High Knees
3 Butt Kicks
4 Shuffle Step (facing sideways)
5 Facing net, Shuffle Step from hash mark to outer sideline; shuffle back to hash mark; sprint to net
6 With both feet, hop back and forth over baseline for a few hops; then sprint to net
7 Big Skip - lower body skips; upper body twists
8 Hip Circles - similar to High Knees, but when the knee is lifted, make a big circle to the outside to loosen the hip joint. I do it on a 3 count so that the circling hip alternates right/left. It goes like this: Step, Step, Circle, Step Step Circle, etc. Some of my students have trouble getting this one.
Two others I like to substitute are deep lunge steps and carioca/grapevine steps.
After 8 rotations my students are usually pretty winded and warm, depending on the size of the group.
For each of the eight activities, students line up on the full court (78-foot) baseline, perform the activity from baseline to net, then circle around outside the court lines and get back in line. If you have a large group, have them form two lines. As soon as one player gets to the net, the next player in line goes, so they need to pay attention. If you have a small group and no lines are needed, they just perform the activity up to the net and do a medium jog back to the baseline.
I sometimes use a different warm-up just to mix things up, but for now this is my go-to warm-up routine 90% of the time.