This work studies the æthiology of the most severe injury in the female handball population. It follows three main lines of research that interact among themselves. A first one attempts to characterise the injury incidence and profile of this population. About 1/3 of all the Portuguese female handball players were sampled retrospectively and/or prospectively throughout 3 sport seasons. The main conclusion is that ACL ruptures are, among the severe injuries, the most occurring ones. A second one attempts to compare statistically the muscular force changes and the ACL injury risk. A strong ACL injury risk predictor is the hamstrings peak torque. A third one consisted in a comparison of the monthly changes in the serum hormonal contents of a few players with both the lower limb muscular strength and the anterior knee laxity. Only a faint correlation could be seen between the hormonal levels and the knee laxity. These findings are mainly negative results but are strong enough for building the hypothesis of a decisive role of the practice load on the risk and prevention of ACL injuries. ukryj opis