Final answer:
Muscle cells regenerate ATP through aerobic and anaerobic respiration, as well as the breakdown of creatine phosphate.
Step-by-step explanation:
Muscle cells get the ATP they need to contract and move you through a process called ATP regeneration. Although there is little ATP in your bloodstream, muscle cells have a high concentration of mitochondria that produce ATP. When there is enough oxygen available, aerobic respiration occurs, generating ATP from glucose. However, during intense exercise or when oxygen supply is limited, anaerobic respiration takes place, converting glucose into lactic acid and generating ATP. Another method of ATP regeneration is through the breakdown of creatine phosphate, which can release energy to regenerate ATP.