In general, cryotherapy affects the body in a number of ways including reducing blood flow to an injured area (thereby reducing swelling), acting as an analgesic (numbing agent), reducing muscle spasm, and reducing tissue metabolism. Because of its ability to reduce blood flow to an area and reduce pain, cryotherapy is the modality of choice for acute injuries.
Acute injuries are injuries that have a known mechanism of injury and usually result in immediate pain. These types of injuries include sprains, strains, subluxations, dislocations, contusions, and fractures.
The most common type of cryotherapy is an ice pack. The most effective ice to use in an ice pack is crushed ice because it conforms comfortably to the contours of the injured area. Crushed ice can also be packed into a thin layer (about one inch thick) placing less weight onto the injured area than a bag filled with cubed ice (can be heavy and result in some discomfort).
There is a technique to making an effective ice bag. Although several companies make custom ice bags for use in therapeutic settings, any plastic bag can be utilized to make an ice bag. Scoop the crushed ice into the plastic bag filling the bag about 1/3 of the way with ice.
The key to a good ice bag is to remove all of the air inside of the bag. This can be done by flattening the ice and pushing out the air or by sucking the air out creating a vacuum inside. Once the air is out of the bag, a knot can be quickly tied in the end of the bag.
The ice can then be redistributed into a thin layer throughout the bag creating a layer of ice with the largest amount of surface space. Once this is done, the ice bag can be applied to the injured area and secured by an ace bandage.
If crushed ice is not available, a bag of small frozen vegetables can be used (frozen peas work really well). Small frozen vegetables can be easily broken up and contoured to an injured area. The advantage of this method is that the frozen bag of vegetables can be returned to the freezer for future treatments.
For individuals sensitive to cold or for young athletes, a barrier can be used between the ice pack and the skin to make the ice pack more tolerable for the athlete. In most cases, a paper towel can be an effective barrier to reduce the impact of the cold on the skin.
For acute injuries, ice packs can be applied for twenty minutes at a time and then removed for 90 minutes to allow the tissue to return to normal body temperature. This can be repeated for the first two to three days to help reduce the amount of swelling.
For injuries to the extremities in which there is moderate to severe swelling around the joint, cold immersion may be a more effective type of cryotherapy. Cold immersion is the use of a bucket or whirlpool filled with water and ice.
The advantages of cold immersion include the ability to quickly reduce the temperature of the entire injured area plus the added advantage of compression through the hydrostatic pressure of the water. The natural pressure of the water exerts a light compression to the tissue assisting with reducing the amount of swelling to an injured area.
Cold immersion is commonly used for injuries to the foot, ankle, fingers, and hands. A number of containers may be used including a plastic bucket, large bowl, or large pan. A container can be filled with water and ice taking care to keep the temperature of the water between 50 and 60 degrees.
The injured body part should be submerged for 10 – 15 minutes at a time. In acute injuries, this can be repeated every two hours for the first 48 to 72 hours.
Cryotherapy for Chronic Injuries
One of the more effective cryotherapy methods to reduce pain and swelling in chronic injuries is ice massage. Ice massage is the use of a frozen cup of water to gentle massage the tissue while receiving the benefit of an analgesic. The injured area is gently massaged with the overlapping strokes moving from distal to proximal (towards the heart).
Ice cups can either be purchased (plastic reusable ice cups) or made at home using Styrofoam cups. To make an ice cup at home, fill a Styrofoam cup with water (leaving an inch at the top) and place the cup in the freezer. When the water has frozen, remove the cup, peel off the top of the Styrofoam cup, and melt any sharp edges of ice by rubbing the ice cup against the palm.
Ice massage is effective to reduce pain in small areas. One injury that is commonly treated with ice massage is shin splints. The painful area is gentle massaged with overlapping motions for 5 – 10 minutes prior to activity and 20 minutes after activity.
Commercial Ice Packs
When ice is not readily available, commercial gel and chemical packs can be utilized. Commercial gel packs are stored in the freezer for at least two hours prior to application. However, because of the density of these ice packs, a barrier should be used between the ice pack and the skin and care taken to check the skin for any signs of tissue damage.
Chemical packs are also effective and are great to use when athletes travel and may not have ice readily available. They are easy to use (shake and apply), but are not reusable. The disadvantage of chemical packs is that they can cause skin burns if the packs break and the contents spill onto the skin. Because of this, care should be taken if using these on or around the face.
Cold Compression Units
In a clinical setting, an athlete might be treated with a cold intermittent compression unit. These units typically come with a variety of sizes of sleeves (half leg, full leg) for the upper and lower extremity. The individual sleeves are placed under the extremity and then zipped on. Once in place, the unit circulates cold water through the unit while applying intermittent compression.
Although expensive as a modality, a cold compression unit is one of the most effective modalities in removing swelling. This unit is ideal for removing swelling from an acute ankle injury. An athlete with an ankle injury can be placed in a cryoboot unit with moderate swelling around the ankle at the beginning of the treatment time, and then remove the ankle 20 minutes later with minimal to no swelling.
Regardless of the choice of ice application, cryotherapy is an asset in the field of sports medicine and is essential in treating acute and chronic injuries.
Read about treating sports injuries using the P.R.I.C.E. principle - Protection, Rest, Icing, Compression, Elevation.
Anderson, M.K., Hall, S.J., Martin, M. (2005). Foundations of Athletic Training: Prevention, Assessment, and Management. (3rd Ed.). Lippincott Williams and Wilkins: Philadelphia, PA.