What ultimately stops muscle stimulation when the motor neuron ceases firing?

When a motor neuron ceases firing, the release of the neurotransmitter acetylcholine at the neuromuscular junction stops. As a result, the muscle fiber no longer receives the signal to contract, leading to the closure of ion channels and the cessation of action potentials in the muscle membrane. Consequently, calcium ions are actively pumped back into the sarcoplasmic reticulum, resulting in muscle relaxation. This process ultimately halts muscle stimulation and contraction.