The Scotland captain believes he can match any midfielder in the Premier League.
“Doing weights is a big thing for me now, whereas before it didn’t seem to have much effect,” he told The Sun.
“It’s small percentages of improvement that help you become a better athlete and player.
“Fitness has never been a problem for me, but in terms of strength and power my gym work has made a real difference.
“Striking the right balance is important, too. There’d be no point in me bulking up if that was to the detriment of being able to get around the pitch.
“I wanted to get to a level where I had strength, but also the stamina to keep going over the 90 minutes. I think I could still put on more weight without affecting my fitness.”
“There’s a long way to go yet in the title race, but this game could be important psychologically,” he told Inside United magazine.
“We know we’re capable of going there and winning. It won’t be easy, but we’ll go there with a game plan and the manager will have a lot of options for the side he wants to pick.
“It’ll be a great challenge at Stamford Bridge. They’ve got a great record there, but we are capable of going there and winning.”
