I have said it for years. I have debated in person, on line and in writing. Finally, justification.
According to the Journal of Strength and Conditioning, using ice to aid in recovery has been shown to slow muscle repair.
If your muscles ache and there is no swelling, you are much better off letting it rest and get better on its own. Stay away from ice.
Doc’s Thoughts: Ice constricts. Heat moves.
Pain is viewed as energy and/or blood stagnation. The end result of this stagnation, among other things, is pain. The key is to move the stagnation. As such, heat is the major way of doing this (acupuncture, massage and several other therapies are effective as well).
Adding cold packs will numb the pain but in the long run, it will add to the stagnation. It is akin to taking an aspirin for repeated headaches. Yes, you may temporary alleviate the pain, but unless you get to the root (the stagnation), you will never have complete healing.