You should stretch before you play, and you have to warmup before you stretch. An easy way to warmup is to do some running on the spot for about 2 minutes.
Rotate the shoulders forward and back keeping your arms by your sides 10 revolutions each way. Rotate the arms one at a time forward and back 10 times each. Then both arms together in opposite directions.
From the press up position above, bring the right foot forward to the hands. Keep the back leg straight. Hold for 10 seconds then change legs. Repeat 3 or 4 times.
Raise one leg to hip height and rest it on a chair, table or step. Keep the leg and back straight, bend forward at the hips until you feel the tension in the back of the leg. Hold 10 - 15 seconds. Repeat each leg 3 or 4 times.
Standing up, bend the leg up behind you and grab the foot. Pull up on the foot keeping the front of the body and leg in a straight vertical line. Hold 15 - 20 seconds. Repeat 3 - 4 times.
Sit down. Keeping one leg straight, place the other ankle on the thigh. Grasp the toes in the other hand and rotate the foot clockwise and then anti-clockwise 20 times in each direction. The foot should move evenly with no jerking movements. Firstly relax the ankle and then try to rotate the foot using the ankle muscles as well as the opposite hand.
Hold the arms at shoulder height, bent at the elbows with the wrists one above the other. Rotate the hands around each other forwards and backwards. Relax the wrists. Rotate 20 times each way. This exercise is very important for underwater hockey as a supple wrist is necessary for controlling and flicking the puck.
These exercises are just a few of the stretching techniques that may be used, however they will ensure that the muscles are warmed up and supple before you play. This will mean less muscle related injuries such as cramp, a quicker warmup time during the game and little or no stiffness after the game.
Stretching should be done before every training session and game. It is also useful after the exercise - especially if it was intense. But how many people do stretch? How many of those that don't get cramp during a game? Most of them say that they stretched before hand but did they do so for long enough and did they do it properly? My guess is that the answer is "NO" to both of these.