Cheetah-like design raises running debate
South African sprint star Oscar Pistorius captured the world's imagination when he fell at the beginning of a 200m heat at the Paralympics in Athens last year. Scrambling up, he went on to win the race in then the fastest time ever recorded by a double-amputee - 23.42 seconds.
Pistorius has since knocked a full two seconds off that time, and has added 100m and 400m double-amputee world records to his list of accolades, distances where he also holds the record for single-amputees.
In fact, Pistorius' race times are falling so fast there is talk of a bid for both Paralympic and Olympic medals in Beijing in 2008.
Nicknamed 'the fastest man on no legs,' Pistorius set those records using prosthetic limbs designed especially for sprinting by Icelandic firm Ossur.
Made from carbon fibre, the Flex-Foot Cheetah is designed to return downward pressure into forward and upward momentum in the same way as the hind legs of a cheetah.
The limb flexes and bends, impersonating foot ligaments and muscles.
But with Pistorius' sprint times already challenging those of able-bodied athletes - he is about two seconds off Michael Johnson's 200m world record - there is a danger the 18-year-old could become the victim of his own success.Already, questions are being asked about the amount of spring effect coming from those carbon fibre blades. Those questions will only intensify as his times get faster.
The issue carries with it considerable moral baggage, and is one athletics' governing body the IAAF will have difficulty in resolving.
Essentially, the question is whether, in purely sporting parlance, technical advances in prosthetics have created a situation where amputees have an advantage over able-bodied sprinters, or whether Ossur has succeeded merely in creating a limb that allows disabled athletes to perform at the level they would if their limbs were intact.
In fact, Ossur states the latter is not yet true, although they strive to achieve it.
The muscles in a human leg return more than 200 per cent energy to the body when running, whereas the prosthetic is far less powerful at 95 per cent.
That still represents a considerable advance in the past decade, and disabled athletes are now closer than ever to 'living without limitations' - Ossur's stated aim.
But as the level of interest in disabled sports increases, and the stakes continue to rise, issues such as acceptable materials to use and the 'spring effect' of prosthetics will inevitably become more prominent.
