Final answer:
Apply an ice pack to a muscle strain for 20 minutes every two hours to help reduce swelling and pain. This is part of the PRICE first aid protocol. The icing should continue for several weeks during home therapy.
Step-by-step explanation:
For a muscle strain, one should apply an ice pack for 20 minutes at a time. This is part of the first aid protocol known as PRICE, which stands for Protection, Rest, Ice, Compression, and Elevation. It is recommended to ice the strained muscle every two hours to help reduce swelling and alleviate pain. After initial first aid, during physical therapy, a heat pack may be applied to enhance healing by drawing blood to the area, followed by a series of exercises and then icing to decrease inflammation. The application of an ice pack for 20 minutes should continue for several weeks as part of the therapy at home.