Ideas for kicking only workouts

Greetings all! I'm experiencing some mysterious swimming-related shoulder pain for the first time in my life - bummer. In the meantime, I'd like to do some workouts that only involve kicking while I address the shoulder issue w/ rest and pt. Any idea on some good workouts? I'm a 39 y/o Masters Swimmer in pretty good shape who routinely does 3,500 - 4,500 yard workouts 4x week when healthy. I'd like to incorporate Zoomers in these workouts. Any suggestions would be greatly appreciated. My apologies if I'm posting in the wrong area. Thanks in advance!