Drawing from the pragmatic sociology initiated by Boltanski and Thévenot, this study bears on the moments of tension between nature’s dispositions and technology’s possibilities in sporting events. It is based on the premise that the deep meaning of sport competitions and their staging are best perceived when strange or foreign forces (an overly ‘bouncing’ prosthesis, an overly masculine body) comes and undermines the reality tests which constitute the events. Through a cross-analysis [in the sense lent to this term by Passeron and Revel], of two athletes whose sporting achievements generated debates – Oscar Pistorius and Caster Semenya – we will underline the fundamental role of technology, which consists in instituting, in secret, reality that is always more significant from a sporting standpoint.