stretching off before doing any physical exercise in the cold (even woodsball) is a must as you could damage muscles as you do a lot of sprinting/running and then sitting about and stretching off afterwards aswell as that's when the lactic acid builds up in your muscles and you then get cramp........Thermals are your best bet, not to thick and will keep you warm throughout the day. Do you really do stretches before a game? Or does that mostly apply to tourney teams as they have to be quick off the mark? Hmm interesting..