Intervention and measurements
The first week was the control week for all participants (no ortho-sis during sports) and the second week was the intervention week where 25% of the participants used a patellar strap during sports,
25% used sports tape, 25% used the placebo condition and 25% used no orthosis during sports. Allocation to the condition in the intervention week was performed at random (dependent on entry
in the study), after stratification for severity of injury. The severity of injury was based on the four phases defined by Blazina et al. (1973; adapted by Roels et al., 1978; Lian et al., 1996). Before the
study, participants received thorough instruction on how to admin-ister the orthosis assigned to them, followed by a supervised prac-tice session. The orthosis was only used during sports activities and it was removed immediately thereafter.