US skeleton racer Zach Lund is using an indoor rowing machine as part of his fitness training for the 2010 Vancouver Olympics.

Lund has been training for the Olympics at the specialist fitness centre Gym Jones, according to Associated Press, which is also used by members of special military units, mixed martial arts fighters, extreme-sports competitors and actors training for film roles requiring them to be in robust physical shape.

The 2007 overall World Cup skeleton champion follows an intense cardio workout programme including a warm-up on an indoor rowing machine, followed by squats and thrusts using a 105 pound weight, alternated with pedalling furiously on a stationary bike.

"There's a difference between being what most people think is in shape, looking good, and being strong, explosive and fast," Lund told the news agency.

Indoor rowing machines are highly effective for fitness training in any sport that requires high levels of endurance and strength.

As well as exercising a range of muscle groups, rowing is also a low-impact activity, making it ideal for anyone who suffers problems with knee and hip joints.