A former partner of mine was a massage therapist. When she was in training, she learned that technique, and explained it to me. When she got home, from practical training, or when she began employment, my job was to pour out the bins full of water, just as you described. One with Ice, and other just cool enough that you could enter it's heat without being too hot. As a railway labourer, I have used the technique often to very good effect on my tired, over-stimulated muscles.