Rest: Rest your muscle to allow your injury to heal. When the pain decreases, begin normal, slow movements. For mild and moderate muscle strains, you should rest your muscles for about 2 days. However, if you have a severe muscle strain, you should rest for 10 to 14 days. You may need to use crutches to walk if your muscle strain is in your legs or lower body. Ice: Put an ice pack on the injured area.