Muscle Metabolism

Energy rich fuels like glucose cant be used directly for muscle contraction.  They must be converted to ATP (adenosine triphosphate) first.  ATP is a substance that stores, carries, and releases energy.  During contraction ATP enables myosin and actin to interact.  ATP is created inside a muscle fiber by two types of cell respiration: aerobic or anaerobic.  A muscle fiber contains enough ATP to power a few seconds of contraction.  Afterward, contractions of ATP need to be maintained at a steady level.