The Deadly See- Saw

The continual see-sawing between the two positions caused the victim to suffer intense pain but the process did not kill quickly. Only if the legs failed would the victim die of suffocation 

The victim would have no choice but to continue replaying this painful see-saw, as to stop would mean suffocation. Yet each cycle would increase the pain and stress being suffered. The victim would suffer cramps and muscles spasms and yet would have to continue to the cycle just to keep breathing. The pain and suffering must have pushed the body to its very limits before the victim  finally died. The only possible releases were to be cut down or to have the legs broken and so suffocate quickly.