Final answer:
Muscle contraction occurs in three phases: latent period, contraction phase, and relaxation phase.
Step-by-step explanation:
Muscle contraction occurs in three phases: latent period, contraction phase, and relaxation phase. During the latent period, the action potential is being propagated along the sarcolemma. In the contraction phase, calcium ions bind to troponin, tropomyosin moves away from actin-binding sites, and cross-bridges form, causing sarcomeres to shorten. Finally, in the relaxation phase, tension decreases as calcium ions are pumped out of the sarcoplasm and cross-bridge cycling stops.