I lost a bunch of hours yesterday trying to figure out if I needed to keep torturing myself with potfuls of ice water. The most researched information and recommendations I could find were in Cryotherapy in Sports Injury Management by Kenneth L. Knight (1995, p. 89, 91) and Therapeutic Modalities: The Art and Science With Clinical Activities Manual by Kenneth L. Knight and David O. Draper (2007, p. 216-233). Knight (PhD, ATC, FACSM) has “dedicated his professional career to understanding cryotherapy,” according to the back cover of his book AND he looks sensible in his picture, so I’m going to trust him. (We’ve reached the depths I’m willing to plumb this topic. Dust jacket endorsements and glamour shots.) Anyway, Knight says the usefulness of cold therapy depends on the phase of the injury. Applying ice to a sprained ankle right after you’ve sprained it speeds healing because the cold slows cellular metabolism and prevents further tissue damage. Tissue that wasn’t initially hurt can be damaged later because it doesn’t get the oxygen it needs. Damaged cells release nasties (my word, not Knight’s) that cause swelling. Swelling retards healing. Anyway, if you make the cells nice and cold, metabolism slows and they don’t need as much oxygen and don’t release the nasties. Wahla! Knight says the ice needs to be on for 30 to 40 minutes to decrease cellular metabolism effectively — and you’ve got to get it on as fast as possible.
Later, during rehabilitation, cold is useful because it decreases pain. If there’s less pain you’ll be able to exercise the injured site more, — which speeds healing by increasing blood flow, metabolism and lymphatic clearing of cellular debris.
And as far as PF goes — and, maybe its evil twin tibial tendonitis, — well, Knight says there’s no good evidence that icing decreases inflammation for overuse injuries. (It might, just no evidence up to Dr. Knight’s standards.) Numbness decreases pain, which allows for exercise. So that’s good. He says you only need 12-20 minutes to numb up a body part depending on how much fat there is. My feet are not fat, so I’m going to see if twelve minutes of ice torture will do the trick today. And what will I do with those extra eight minutes? Hard to say. Lots of cat hair on the couch; Guess I do something about that… How long does it take to eat a whole cantaloupe?
And, of course, for the record, I’m not recommending anyone out there do what I’m doing. I’m just curious and like to read textbooks. (You heard me!) I can help you if you fall down in front of me and start swelling/bleeding and I can get you evacuated from there if necessary, but that’s about where my athletic injury qualifications end.