Adnan Januzaj has been spending extra time in the gym in an attempt to bulk up and become faster.
Januzaj enjoyed a stunning breakthrough season under David Moyes last year, but he has struggled to make the United XI on a regular basis since Louis van Gaal took over.
The 20-year-old has started just seven Barclays Premier League games under the Dutchman, although a change in formation - and the poor form of Angel Di Maria - means the Belgian has gained more playing time on the wings as a substitute recently.
Januzaj revealed recently that he prefers to operate as a number 10, but Van Gaal looks set to continue playing him out wide given that Di Maria is suspended for Sunday's game against Tottenham.
And the slight Belgian has been putting in the hard yards in the gym to ensure he is capable of taking on and beating defenders for pace.
"I do a lot of work in the gym. I am trying to be faster and stronger so I can be tougher when I go out on the pitch," Januzaj told United's website.
"I am doing a lot of short, sharp stuff so, when I turn a defender or go past a player, I can just get a few metres away from them with my acceleration."
United fans are used to watching fast wingers speed up and down the flanks at Old Trafford, but more often than not, they have been subjected to slow, unimaginative performances from their team this season.
United may have lost just two of their last 18 Premier League games, but Van Gaal has come in for criticism because of the team's style of play.
Former Barcelona and Chelsea assistant, Henk Ten Cate, who spent a year with Van Gaal while he was doing his training badges, thinks United should stick with his compatriot though.
"You have to give him time because, for me, he is one of the best coaches there is," Ten Cate told talkSPORT.
"I worked closely with him for one year when I was going through the stages to get my coaching licence. I saw what he was doing and the only thing he has to do is get used to the way of playing in England.
"If the owners of the club gave him that much confidence and that much money to spend, it is not a good thing to say goodbye to the coach after one season because it is starting to become his team.
"He needs a little more time but I am almost positive that he is going to surprise Britain with his (style of) football."
Ten Cate admits United's play has not been up to Van Gaal's standards so far, however.
"I know him well and he is the kind of guy who doesn't just go for results, he wants his teams to play good football. He has proved that in the past," Ten Cate said.
"Right now at Manchester United the way they are playing is absolutely not good. But it is not the style of Van Gaal."