Andy Murray pictures show added muscle ahead of Australian Open 2013

Muscle-bound Murray shows off bulked-up frame ahead of latest shot at Aussie Open

has left him hungry for more.

Murray enjoyed a breakthrough season last year when he became the first British male to win a grand slam in 76 years with his success at the US Open, while he was also crowned Olympic champion during a fairytale summer for the Scot.

The world No 3 is not ready to settle for that, though, and has spoken of his determination to keep on improving and adding to his title collection.

Andy Murray

Murray looks on during practice ahead of the Australian Open

Watch out, Australia: Andy Murray practices serving as coach Ivan Lendl looks on at Melbourne Park

Murray serves as his coach Ivan Lendl watches on during practice at Melbourne Park

Focused: Murray has his sights set on the Australian Open, which begins next Monday

Murray serves as his coach Ivan Lendl watches on during practice at Melbourne Park

Murray once again spent December building his fitness at a gruelling training camp in Miami before flying home briefly for Christmas and then on to Australia via the Middle East. While in Florida, Murray worked hard on his physical strength, doubling his weekly weightlifting sessions from two to four, in a bid to boost his shot power.

The result is an added three pounds of muscle to his already impressive frame. And, judging by the impressive pictures taken of the Scot in practice in Melbourne today, he is in peak physical condition ahead of his latest tilt at the year's opening grand slam title.

Speaking ahead of the upcoming Australian Open, where the 25-year-old will aim to improve on runners-up finishes in 2010 and 2011, Murray told the Daily Telegraph: 'The US Open and the Olympics made me extremely motivated.

'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.

Murray has been hard at work building his fitness over the winter

Murray has been hard at work building his fitness over the winter

What a specimen: Murray has been hard at work building his fitness during the break over the winter

Murray has been hard at work building his fitness over the winter

'I know the feeling when you do win them now and it’s worth all of the work that you put in.'

Prior to his success at Flushing Meadows, Murray had won 22 singles titles but had never managed to go all the way in a grand slam tournament, tasting defeat in four finals and reaching numerous semi-finals.

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.'

Although Murray has been working hard on the physical side of his game, he is adamant that the real difference between victory and defeat comes from brains, not brawn.

The Scot's love of boxing is well known – he counts David Haye as a close friend – so he was thrilled to meet former undisputed heavyweight champion Lennox Lewis while filming for the BBC's SPOTY programme, where the pair talked training – and winning.

'Heavyweight boxing is the pinnacle of sport really, especially when he (Lewis) was fighting,' said Murray. 'So to get to pick his brains about certain things was nice.

'I asked a lot of questions about current boxers and how you train. He was saying boxing is 70 per cent mental, 30 per cent physical in the actual talent you need, and I think that applies to a lot of sports.

'The difference in how guys hit a ball is not that huge, but it’s about how you deal with the pressure moments and who can hold their nerve.

'When you get towards the end of sets, some guys make more mistakes than others.'


Murray at Melbourne Park last year

Murray flexes his muscles back in 2009

Murray's torso is noticeably less ripped during practice at Melbourne Park last year (left) while, despite his best Incredible Hulk impression, his still-impressive physique from 2009 (right) is not as muscular as today