Which process must occur for a muscle to be able to relax?

The process of muscle relaxation begins when signaling from the motor neuron stops. This event causes repolarization of the sarcolemma and T-tubules and closes the voltage-gated calcium channels in the sarcoplasmic reticulum (SR). As a result, Ca + ions are then pumped back into the SR, which causes the tropomyosin to re-cover the binding sites on the actin strands.

When the amount of ATP runs out, the muscle also relaxes.

The muscles exhibit the tendency to relax by a procedure known as relaxation.

Explanation:

After the stimulation of nerve takes place, the process is known as relaxation occurs. The association between the actin and myosin gets dissociated when the pumping of calcium takes place back into the sarcoplasmic reticulum. As the actin and myosin return back to their unbounded condition the relaxation of muscles takes place.