The day before a game is no longer a time for the 49ers to hold a brief, walk-through practice and get off their feet.
One of the changes that Kelly has brought to the 49ers is a new philosophy on how to spend the day before games.
On a typical week in which the 49ers play a Sunday game, Kelly gives the players the day off on Monday.
"We practice Tuesday, Wednesday, Thursday with Wednesday and Thursday being our biggest days," Kelly said. "Friday we back off a little bit and then Saturday we practice a little bit faster."
Kelly said the reason he does not believe in holding low-speed practices on the day before a game is based on science.
And what does the science say?
"That you should practice faster the day before the game," Kelly said.
Two years ago while head coach of the Philadelphia Eagles, Kelly expounded on his thoughts during an interview on the Ross Tucker Podcast.
"Through our research, through science, (we learned) that you need to get the body moving if you're going to be playing," Kelly said. "We used the same formula at Oregon and I spent a lot of time on how to go about it, how we think you should train, and it worked for us there and it worked for us here."
Kelly has previously said he talked with trainers of Olympic athletes and those experts believed athletes should remain active in the 48 hours before competitions.