For high school football we would take cold water baths in the tubs we had in the training room. They really seemed to keep our legs fresh through the week.
On the video, WTF... just weird.
But it reminds me of guys in high school who would try to get the water as cold as possible and then see if you could stay in it for 10 minutes or longer. We had an ice machine and would dump ice by the bucket in the water. I think the coldest we got it was about 42 degrees Fahrenheit. I think the longest anyone would stay in is about 20 minutes.