The cool down process is not complete until you re-fuel. Your body lost water and nutrients as you played so it is now time to replace them.
Make sure to drink lots of water and sports drink after your work out and eat something within that first hour after you finish because that is when the body is best at delivering the nutrients that your muscles really need.
There is more on nutrition and hydration in previous articles and they are key elements of your cool down from playing volleyball, so make sure you include this element to complete your post-workout process.
