Cryotherapy is often used in soft tissue sports injuries. The application of a cold pack reduces local muscular blood-flow by approximately 50% after 10 minutes. The duration of bleeding in a muscular injury is not known, but immediate application of external pressure is probably far superior in emergency treatment of an injury. Some studies have shown significant effect of cryotherapy in emergency treatment of ankle sprains, but external pressure is often applied simultaneously and the additive effect of cryotherapy is therefore uncertain. Cryotherapy reduces the metabolic rate in injured muscle and is often used several days after a soft tissue injury to reduce secondary hypoxic injury. Experimental studies, however, show no effect of cryotherapy on muscle regeneration, and no controlled clinical study has shown a significant effect in emergency treatment of soft tissue sports injuries.