seated calf raise (on machine).
this one is sure to make your calves burn. i like to start with moderate weight and 12 reps, then gradually increase the weight as i decrease the reps for each set.
start with your legs straight, toes bent up toward your face. keep your back straight. there will be tension on the machine.
push up on your toes, using your calves (not your quads) to propel you. flex your calves when you are up in this position: