Getting the right amount of sleep is vital to achieving your goals when it comes to training.  Research has shown that getting 8 hrs a night will help repair muscles after training as growth hormone is released while you are in a deep sleep.  Also a study by Stanford University has shown that getting 10 hours of sleep a night can improve your sprint times by 8 %.  The study also showed that it will also increase power and reacrion times. 

Source: Mens Health