Senner [ 38 ] has developed, together with Lange Ski-Boots, a flexible rear spoiler able to decrease ACL injuries. The rear spoiler flexes only when the backward moment exceeds a certain threshold value, yielding of only a few degrees. The results of his studies indicate that a flexible rear spoiler permits a reduction in tension forces on the ACL and the yielding may also produce positive effects on muscles. The data obtained by Senner have been used by Van den Bogert [ 39 ] to build a computational model to study the effect of ski-boot design on knee ligament injuries. The effect of the lateral inclination was also studied by Senner et al . [ 40 ] concluding that canting settings are able to reduce the misalignment but only by about 10%. Increased ski-boot canting settings would therefore be desirable. Knee kinematic studies have also shown [ 40 ] that rotational misalignment could not be linked to any significant increase in injury risk.