The body needs time to prepare for any intensive athletic exercise and warm muscles not only perform better, but are less likely to tear. Send your players into a gentle jog around the outside of the pitch, with the coach standing in the center of the field. Once the players have completed a half lap of the pitch mix up the exercise with the following calls
"One" at the command one player continue jogging but place their hands down behind their backside. They should flick their heels as they run so that the back of the foot touches their hands.
"Two" at the command two, player continue jogging but this time raise their knees to waist height with each step. This practice of high stepping and lifting the heel off the ground can also be seen in the preparation of many top class sprinters as it encourages a cyclical nature to the running stride which creates the most efficient results.
"Three" touch the sky. Players continue jogging but on each third stride spring up with their hands reaching for the heavens.
"Four" a five yard sprint. This command should not be given until both "One" and "Two" have been performed at least once.
Don't let your players travel around the pitch more than twice. Coaching sessions are not the place to build up fitness, and three plus laps around the pitch once a week will not correct this in players either young or old. Players are responsible for their own fitness - inflicting endless laps on players who already have the requisite levels becomes a frustration, and kills the buzz of your session. The warm up should be sharp, snappy and just long enough to get players warm for skills work.