The test population consists out of students of the physical education department. They will at random be divided in three groups. One group will wear the shoe only for daily activities, the second group will wear the shoes for the warming up part of the sport classes and the control group will not wear the shoe at all. There will be two moments for evaluation: one at the beginning of the study and one after four months, during which the shoe will be used. The isokinetic strength will be measured with an isokinetic device (Biodex) and the proprioception will be evaluated with a force platform (Neurocom Balance Master).