Actually the explosive movements that you see sprinters often do prior to entering the blocks helps to prime their nervous system for an explosive start. Remember, the guys you see on TV have often gone 5-10 minutes between their last warmup activities and the time they get to the start line. Their final actions are a way of getting in a final tuneup without disrupting the flow of the meet (high level meets are run on a very strictly enforced time schedule).
ELITETRACK Founder