What are the sources of energy for muscle contraction?

ATP is obtained from several sources including:

• Creatine phosphate, a high-energy molecule that’s stored in muscle cells. ADP converts to ATP by obtaining a high-energy phosphate group from creatine phosphate 
• Glucose stored within the cell generates ATP by cellular respiration
• Glucose and fatty acids that are absorbed into muscle cells from the bloodstream generate ATP by cellular respiration

In addition, ATP is also stored within the muscle fiber.