From a report at the link below:
For decades, the standard method for treating injuries was RICE - Rest, Ice, Compression, and Elevation.
Everyone from Little League coaches to pro sports trainers knows icing is a sure way to reduce swelling, inflammation and pain, and speed healing. That has been the conventional wisdom.
There is a self-published book by Gary Reinl that says that icing is not only wrong but is also counterproductive and harmful.
"There's not a shred of evidence that icing is helpful," Reinl said. "To the contrary, it does the opposite. It delays healing, it increases swelling, causes additional damage, and shuts off signals that alert the body to harmful movement."
Full report here.