Creatine does bring about an enhanced accrual of strength in weight-lifting programs.
However, creatine will not improve aerobic exercise performance or maximal isometric strength. When you eat food, your body breaks it down into packets of energy called adenosine triphosphate, or ATP, that muscles and organs can use. However, to make ATP, the body needs a ready supply of something called phosphocreatine, and as muscle stores of this get low, athletic performance suffers. Extra creatine can increase these muscle stores in most people, leading to faster regeneration of ATP and decreased rest time between exercise bouts. These rats not only had worsening kidney function, but also increased formation of cysts in their kidneys.