 The lightness and rigidity of the blade compared to muscle and bone may allow blade runners to swing their legs faster than non-disabled runners.In comments on the article, Peter Weyand and biomechanist Matthew Bundle noted that the study found that Pistorius re-positioned his legs 15.7% faster than most world record sprinters, allowing for a 15–30% increase in sprint speed.In 2008 a research team including Alena Grabowski, Rodger Kram and Hugh Herr conducted a follow-up study of single amputees with running blades which was published in "Biology Letters".