The five-step process for treating an injury to a muscle or joint is called "P.R.I.C.E.", which is short for Protection, Rest, Ice, Compression, and Elevation).
It can be used even by someone without first-aid training, and should be used immediately when an injury occurs – the earlier, the better – while further medical attention is being sought.
If the athlete experiences too much pain during the process, stop immediately.
"P" is for Protection
Protect the injured person and the area being treated but also protect yourself. If the injury occurs on the sports field, stop the game.
Protect the area being treated with a splint if possible.
If the athlete can move, carefully move them to a safer area using a stretcher or a crutch, but if there is any doubt, do not move the injured athlete.