The Chip Kelly approach to football is not restricted to his revolutionary offense on the field.

He obsessively utilizes the best sports science available to ensure his athletes are doing exactly the right amount, and right kind of work to get better each day.

Take new running back DeMarco Murray. Last year with Dallas, Murray led the NFL in rushing with 1,845 yards on an eye-popping 392 carries.

Simply limiting his carries (he will split his workload with Darren Sproles and Ryan Mathews) isn't enough for Kelly in his quest to maximize Murray's health and output.

Sensing he wasn't quite hydrated enough during Sunday's first training camp practice, Murray sat out 11-on-11 drills after participating in team drills.

"We monitor guys in a lot of different was," Kelly said. "If we find out a guy isn't hydrated enough, which puts him in a more susceptible situation to injury, that's what out sports science program is here to do."

Murray of course was fine Monday and Tuesday, taking his usual reps with the first team offense. But despite being perhaps the fittest Eagle, he is still subject to the necessity of being fully hydrated throughout practice.

"If you don't have the right amount of liquid and electrolytes in your system it doesn't matter how fit you are," Kelly said.

The program starts each day with an iPad survey for each player to find out what kind of shape they are in heading into practice. Then the player's output is measured throughout the day as well as several vitals, and other pieces of useful information to the medical and coaching staff.

"We have full monitors on everybody," the coach said. "We have full GPS systems, heart monitors and other things so we can prevent injuries before they happen."

Kelly went on to point out, after some playful jabbing from Eagles reporters Tuesday that the GPS system only works on the field and not when the players leave the Eagles practice facility.