The running back and wide receiver simultaneously jumped into a cold tub to raise support and awareness for ALS, more commonly known as Lou Gehrig's Disease.
The premise of the challenge is simple. If you're challenged, you have 24 hours to either dump a bucket of ice water on your head (or in this case, jump into the cold tub) or donate money to research to help cure ALS. Or, theoretically, do both.
Many NFL players and celebrities have participated in the cause, including commissioner Roger Goodell and New Orleans Saints quarterback Drew Brees, along with many other people who have been posting videos on Facebook and Instagram.