Ice is most commonly associated with immediate first aid to an acute injury because it causes decreased blood flow and an increase in deep circulation as well as superficial vessel constriction. Ice decreases pain and muscle spasticity and enables you to exercise easier, but does not mask the pain.
Ice also allows increased circulation to carry away waste products and aid healing.
Immediately apply ice in a bag with modest compression to the area for at least 15 minutes or until the area gets red and numb. Try to get beyond the initial painful feelings of the cold skin. Or, ice massage the area with an ice cube or ice cup directly to the skin for 7 to 10 minutes - or until the area gets red and numb. Apply ice every 2 hours for the first 48 hours. If inflammation and swelling persists, continue to ice until the swelling goes down.