Which of the following is a method of cryotherapy?

Cryotherapy refers to the use of low temperatures in treatment, primarily to reduce inflammation, swelling, and pain, among other therapeutic effects. Ice packs are a classic method of cryotherapy, as they apply cold directly to an injury or area of discomfort, promoting vasoconstriction and numbing the affected area. This method is effective in the immediate management of acute injuries and helps to alleviate pain and reduce inflammation.

In contrast, heat packs, ultrasound therapy, and moist heat packs all incorporate heat rather than cold, categorizing them as thermotherapy methods rather than cryotherapy. These therapies have different physiological effects, primarily benefiting muscle relaxation, blood circulation, and the relief of chronic pain, rather than the acute management that ice packs provide.