THERE are plenty of ways to win the battle of the bulge - the question is which form of exercise will get you on top of the fight fastest.

Walking, running and cycling are three of the most popular physical pursuits in Australia, but fitness experts say there is no simple answer to which is best for the body. Australian Institute of Sport senior sports scientist David Martin said the physical benefits depended on "training volume" - the duration and intensity of any given activity. "But instead of it being a really clear-cut formula, one of the first questions to ask is what you enjoy the most," Dr Martin said.Australian Bureau of Statistics data showed that

an estimated 1.5 million Australian men walked for exercise, compared with 2.8 million women. Almost 876,000 men rode a bike for fitness, while 775,000 jogged. Women were more likely to run - 585,000 compared with 491,000 who cycled.AustCycle general manager Gareth Watkins said cycling was gaining in popularity, particularly with middle-aged men and women.

Dr Martin said all three pursuits had benefits and drawbacks. Cycling was non-weight bearing, making it good for existing knee, ankle or hip problems, and it was a relatively social sport compared to running and walking."But it can be expensive and the thing about cycling is it's usually done on the road," Dr Martin said. "Since I started working with elite cyclists in 1994, I've been involved with five cyclists who have died."Walking, meanwhile, was attractive because almost anyone could do it.

However, it required one to two hours of exercise on flat ground to burn a decent amount of energy. Pushed to nominate the activity likely to have the most benefits, Dr Martin choose running.

"You don't have to go out and buy equipment or learn the techniques of riding and you won't have a massive impact on your day by going out on long walks," he said.

Professor David Bishop, research leader at Victoria University's Institute of Sport, Exercise and Active Living, said running burned more energy than walking as it meant lifting your body mass higher off the ground but it could lead to stress-related injuries."What goes up must come down," he said.

Australian Orthopaedic Association president Dr John Owen said the worst injuries from the three forms of exercise usually came after bike falls, mainly high-energy ones.

Exercise also has mental benefits and Black Dog Institute psychological services director Associate Professor Vijaya Manicavasagar said it reduced tension and released endorphins that created a sense of pleasure and satisfaction.

Originally published as Walking, running or cycling?