Roman crucifixion was considered to be the most painful, disgraceful and horrific forms of torture. The hands and feet were bound and nailed to the cross. The pain was excruciating. There was strain on the wrists,, shoulders and arms. The rib cage was in such a position that it would be difficult to take a full breath.
Because of dehydration and difficulty breathing, there would be extreme cramping of the legs. The length of time required to die could range from hours to a number of days, depending on the condition of the victim before he was placed on the cross. Our Lord suffered extreme beating prior to His time on the cross.
The final cause of death would be lack of oxygen going to the brain, shock and unconsciousness or asphyxiation. This type of punishment was reserved for the worse criminals and would also serve as a reminder of the authority of the Roman Empire.
Jesus died to take our place, so that the curse of the law would be taken away. He died so we could live eternally. Praise be to God for giving us the victory over death.