There are many reasons why you should know how to tread water. Obviously, not drowning is the most important, but if you are considering joining the military and especially special operations, you will be tested in these events. Some of the tests are simply keeping your head above water for a specific time. Some tests are more challenging, requiring you to keep your hands out of the water or hold a weight. Some are done with SCUBA fins with a weight belt, tanks, and hands out of the water. Regardless, many people need help with this skill.
Here is an email from a future Navy Special Ops candidate seeking to practice these weaknesses prior to joining.
Stew – I have a few months before I ship to boot camp and want to master the tread. I am fairly lean (less than 10 percent body fat) and pretty sure I am negative in the water as I tend to sink and have to work really hard at floating and treading. Any tips for me?
Good job working on weaknesses NOW, as they will be exposed during your training. My number one tip is to keep doing what you are doing. Make every swim workout ends with a prolonged tread session of 10-15 minutes just to get used to the suck factor of treading. You have to go into the tread that it is a PUT OUT evolution. Too many people think treading is easier than swimming. I find it just as tough. In fact, I call it Vertical Swimming. If I told you to swim for 10 minutes, you could do that easily and be winded if trying to get a good time. Same goes for treading -- expect to be winded. Expect to be tired. My second tip is to breathe differently than you normally breathe when you run or swim. Treading can be easier if you have a full chest of air in your lungs. To do this without holding your breath for a long time -- "breathe in reverse." This means take a big INHALE, keep your lungs full for about 5-6 seconds, EXHALE real fast (kick hard to stay up) then INHALE again to keep your lungs as flotation devices. It works really well and will require less effort to stay close to the surface.
My third tip is to learn how to kick and play with a variety of kicks. Scissor kick (alternating left / right), little flutterkicks, breaststroke kick, and egg beater kick (see video). Also for a real expert in treading, see any water polo player in action (live or video). My way of teaching the egg-beater is to have people first learn the breast stroke kick, then apply that skill to making the breast stroke and alternating LEFT / RIGHT kick to get into the egg-beater rhythm.
AND my fourth tip – PRACTICE DAILY. You do not need to be a competitive water polo player but you do need to be competent in the water. Practice is the only way to get there. Good luck!