10 x :15 fast/:45 easy
You can warm up by doing about 15 minutes of swimming or water exercise of any type.
The main set requires a flotation belt or vest. You can even use a PFD life vest if you have one and are at the lake instead of the pool. Get into the deep water where you can't touch bottom. Sprint with full range of motion as fast as possible for 15 seconds, and then "jog" easily for 45 seconds. If you are at a pool with a pace clock...use that. Otherwise, you can use a countdown timer on a watch or other method of your preference.
Water running is incredibly effective as a training tool. It's not too popular but it's a great conditioning tool for any athlete. It doesn't matter if you are fit and healthy, injured (in most situations) or have physical limitations.
Cool down from this session with a little swimming and kickboard work.