All three energy systems “make a contribution to exercise,” but the ATP-PCr system generates about fifty percent of the energy used in soccer. Together the glycolytic and oxidative systems are evenly responsible for the remaining sixty percent of energy used. In soccer, players alternate between sprinting and walking, so it is understandable that the ATP-PCr is responsible for such a vast amount of energy. The ATP-PCr system normally lasts for “3 to 15 s”, which would allow a player to “perform short bursts of intense running” (Kenney, W., Wilmore, J., Costil, D., 2015b, p.p. 58; Clark, 2016).…