Sir Matthew Pinsent, four-times Olympic rowing gold medallist, knows exactly how tough it is to win selection for big sporting teams and is now helping the public to get a first-hand taste of the action this February - and raise money for charity at the same time.

The Nation on Trial initiative, sponsored by the GB Rowing Team's high-performance partner Siemens, pits the public against each other and the clock to mark the build-up to the GB Rowing Team's Senior Trials in March by inviting them to get fit, get on a rowing machine and take their own 2km trial.

2km is the distance GB's top stars will race on the water at the Olympic Games this summer but for anyone aspiring to join the GB team the year-long selection process begins with a 2km test on a rowing machine.

All participants in The Nation on Trial will be entered into a prize draw to win a behind-the-scenes trip to the culmination of that process, the Senior Trials, at the Olympic rowing venue, Eton Dorney, and are encouraged to raise money for the event's charity partner The Stroke Association by getting sponsored to complete a training plan or hit a target.

"The trials are something the rowers train for and work towards all winter," said Pinsent who won Olympic gold in 1992, 1996, 2000 and 2004 and had to go through the trials every year of his GB career.

"There is a great satisfaction in feeling yourself getting fitter and stronger and then proving it in a race or a trial, competing against friends or colleagues.

"The Nation on Trial is a great opportunity for the public to get a feel for what the GB rowers are going through as they battle for selection for the 2012 season.

"It's tough, but there are clear rewards," he added. "And by taking part you get to see how close you are to the GB entry standard and understand just how fast the top rowers are.

"I did it for so many years I'm now enjoying my retirement but people should sign up, have a go and surprise themselves with how addictive a rowing machine can be."

Pinsent helped launch The Nation on Trial on the banks of the River Thames at Reading Rowing Club on Friday by putting a number of journalists on a rowing machine to record their 2km efforts before embarking on a tailor-made, month-long training plan to improve.

Anyone of any ability aged 16 and over can register on the event website www.nationontrial.org and access expert training advice from fellow Olympic rowing gold medallist Martin Cross as well as messages of encouragement from World Champions such as Katherine Grainger, Richard Chambers and 1992 Olympic gold medallist and fellow 2012 hopeful Greg Searle.

Rowers can register as many times as they like on the event website which will show how they compare with friends and workmates as well as the entry standard for the GB selection process.

The times for those aged 16-24 will also be assessed to see if anyone has the talent to be considered for Rio in 2016. The event could throw up a new generation of rowers destined for the GB Rowing Team as well as be the nation's chance to keep up their New Year get-fit resolutions as the year turns onwards to February.

Register now at www.nationontrial.org