It's the final sporting challenge for Donovan Bailey, Gareth Thomas, Iwan Thomas and James Toseland. They are off to Japan to master the skill and precision required for the ancient art of horseback archery, known as ‘Yabusame'.Galloping down a straight track at high speed, gripping the horse with just their knees, they will be required to shoot with a bow and arrow at stationary targets and compete against each other.Training starts in the UK with an archery and horse riding session. It's something none of them has done before, and Gareth has to conquer his first phobia – his horse.Finally in Japan for a week of training before they begin, the men get under way learning the life of the samurai.Being back in the saddle travelling at speed brings back old emotions for James, and some aspects of the competition prove too much for Gareth and Donovan.It's their final challenge. Who will be named the ultimate competitor?