They’re principally concerned with his swing time — the interval between his strides. Pistorius’s swing time has been clocked at 0.284 seconds, which is certainly unusual. Able-bodied sprinters rarely exceed a swing time of 0.32 seconds, and the anti-Pistorius camp claims that his advantage in this area is entirely caused by his lightweight blades. As such, they feel he has an unfair edge over an able-bodied field, but this argument ignores two important points. Firstly, Pistorius is the only T43 athlete to have had his swing times measured in this way, and in isolation the data has questionable value. It’s plausible Pistorius’s swing times are to some degree the product of his being an exceptional athlete, and unless it’s proven that all T43 runners have unusual swing times, we can’t discount that possibility. Secondly, the swing time is just one factor that determines a sprinter’s speed, and while Pistorius benefits from a faster swing, he loses in other areas. He is able to apply far less downward force with his blades than an able-bodied sprinter can deliver with an ankle and foot, and he recoups far less energy in return.