Aperson dies, and within hours, the skeletal muscles develop a locked contraction known as rigor mortis. calcium ions leak from the sarcoplasmic reticulum into cytoplasm. what best explains this rigor?

During when we are alive, oxygen is used to make atp, and atp  is used to break cross-brdiges when we are relaxing / contracting our muscles. when a person is dead then there is no oxygen but the body can still produce atp via anaerobic glycolysis, when the glycogen is depleted then no atp is produce so the the cross bridges can no logner be broken that is why skeletal muscles lock