Proper instruction of running form with focus on arm and leg action can improve your players overall speed. You can see from the videos below how some simple instruction can turn an average runner into a great runner with improved times and reduced energy expenditure.
After 15 min of training 20 yard run improved from 3.94 sec to 3.5 sec. Note the improved arm action and running efficiency. That is the net gain of approximately 2 feet of distance gained per second of running.