Pumped-up Andy Murray aims to muscle in on grand slam rivals GONE is the scrawny teenager who once struggled to go the distance in gruelling encounters with rivals Roger Federer and Rafa Nadal. Looking to be in the shape of his life, a more muscular Andy Murray was photographed yesterday as he warmed up for his latest tilt at a grand slam. The 25-year-old, who spent much of December at a training camp in Miami, Florida, is understood to have doubled his weekly weightlifting sessions as he bids to add to his trophy haul at the Australian Open. Riding high, following wins at the Olympics and the US Open last year, the Scot last week successfully defended his Brisbane International title ahead of the first of this year's slams next week. The world No 3 showed off his physique during a practice session in the Melbourne heat after adding an extra three pounds of muscle. "The US Open and the Olympics made me extremely motivated," Murray said. "It wasn't a case of, "Oh, everything's done now." It's taken a long time to get there and to win those sorts of events. I know the feeling when you do win them now and it's worth all of the work that you put in. He added: "In the past, there were loads and loads of questions. I wasn't physically strong enough. I wasn't mentally strong enough. I didn't listen to my coaches. I was spoilt. Whatever it was, none of that really bothers me any more. I'm just looking for ways to keep improving. He also revealed he was inspired by Lennox Lewis following a meeting with the former heavyweight boxing champion. Murray said: "He is a legend and heavyweight boxing is the pinnacle of sport, really, especially when he was fighting. So to get to pick his brains about certain things was nice. David Marshall, chief executive of Tennis Scotland, said: "The singles game is a lot more brutal in terms of what it takes out of you than it was a few years ago. If you don't have the right physique, you're starting from a really negative position. It's difficult to give an exact percentage of how much time they spend in the gym, but it's a major part of the fitness programme. You know with Andy that he will always give it 100 per cent.