Jumper's knee has to be the most common injury that results from playing the game of volleyball. Josh Heenan is the Sacred Heart University Head Baseball Strength and Conditioning Coach and has written an article over on his site about jumper's knee and how to prevent it. Here is an excerpt from the article:
When looking at patellar tendonitis for our athletes; the first area of concern is the ankle. Acute ankle injuries make up a majority of volleyball injuries (Bahr & Bahr, 1997). Injured ankles often lack the proper mobility, mainly in dorsiflexion (e.g. limited motion foot towards the shin). As you can see in the images [above], poor ankle mobility can lead to poor landing mechanics and put more stress to the knee and can irritate any existing knee pathologies or create new ones.
Jumper's knee is something that I've had to deal with, and I'm sure many of you have as well. If you are a player of any skill level or a coach, check out the article and follow Josh on twitter for more updates about injury prevention.