TRC-Physiology for Swimmers, Coaches and Parents Part II Energy Systems In a previous physiology article, we discussed the three different systems that humans have available to produce energy for bodily functions, including muscle contraction.Club Members Only Upgrade to The Race Club Membership – 2, Monthly, The Race Club Membership – 2, Annual, The Race Club Membership – 1, , The Race Club Membership – 4, Monthly, The Race Club Membership – 4, Annual, The Race Club Membership – 4/Gary Hall Sr., Monthly, The Race Club Membership – 4/Gary Hall Sr., Annual, The Race Club Membership – 4, 4-Month Bundle, The Race Club Membership – 4/Gary Hall Sr., 4-Month Bundle, The Race Club Membership – 3, Annual or The Race Club Membership – 3, MonthlyOr Login