Data analysis
Median VAS pain scores and interquartile ranges were calculated per condition. A two-level Poisson mixed-model analysis with overdispersion was used to analyze the difference in VAS pain
score between the four conditions during the three functional tests. A correction for jumping height (for the vertical jump test) and distance (for the triple-hop test) was included. The analysis con-
trolled for study location. In order to investigate the secondary research question – which patients’ characteristics are possibly related to the effect of the orthoses? – a simple linear regression analysis was used. The difference in VAS pain score between the patellar strap/sports tape and the control condition during the 10× single-leg decline squat was used as outcome parameter, and personal characteristics (gender, age, body mass index), sports-specific factors (playing level, jumping height), and injury-specific factors (VISA-P score,unilateral/bilateral PT, duration and exact location of PT) were used as predictors. Previous and current use of an orthosis during sports was also included as a predictor. IBM SPSS version 20 (IBM Corp., Armonk, New York, USA) was used to analyze the data, and a P-value < 0.05 was considered statistically significant.