(REUTERS) - Manchester United striker Romelu Lukaku has attributed his sluggish start to the season to a more muscled physique and said he had been staying out of the gym in a bid to improve his form.
The 25-year-old was United's top scorer with 27 goals in all competitions last term and helped Belgium reach the World Cup semi-finals in Russia, but he has scored just six times in 20 club appearances this season.
"Me and the medical staff did a lot of tests to see what was the problem," Lukaku said after scoring in United's 4-1 Premier League win over Fulham on Saturday (Dec 8).
"I put on a bit of muscle at the World Cup (but) in the Premier League I cannot play with the same amount of muscle as international football. I knew I had to lose muscle so I stayed out of the gym."
The striker, who now has two goals in his last three appearances for United, also said he had suffered from fatigue at the start of the Premier League season.
"After the World Cup, I think I really was a bit tired... I wasn't playing with enough intensity, enough aggression. Now I think I am in a decent level again and ready to go again," he added.
The victory over basement-side Fulham was United's first in four league games and moved Jose Mourinho's side up two places to sixth in the table.