A few weeks back I managed to pull a muscle while swimming. I'm fairly certain it's because I didn't warm up before I got in the pool and did some higher intensity swimming than I normally do. What warm ups are there for swimming so that I can prevent this from happening again?
Your best warmup is going to be swimming. What I usually do for a warmup is a 500m swim of SKIPS. Swim 100m, Kick 100m, 100m IM, 100m Pull, 100m Swim. If you can't do all the strokes, do 400m SKPS.
I might also not make my most intense set the first one after the warmup, I might put in a threshold set of 10x100 on 1:45 (or whatever suits your swimming speed), before I did any kind of high intensity interval type work.
I'm not a fan of leaping around a pool deck waving your arms and legs for a swimming warmup. One, the deck is often wet/slippery, two you get funny looks. Swimming is non impact enough that you can just get in and swim at a low level, so as long as you don't jump in and start banging out 50m on a :25 sendoff you should be fine just swimming as a warmup.
Warm ups are important for all sports, both physical and also a mental warm up. Here are some warm ups for swimming:
Various warm up drills for swimming that are integrated in a swim workout can be found at - for example - Swim work out generator