Patellofemoral joint forces during running are not different between adolescents with and without patellofemoral pain-a cross-sectional study.

INTRODUCTION

The purpose of this study was to determine if adolescents (aged 12-18 years) with patellofemoral pain demonstrate greater peak and cumulative patellofemoral joint forces when compared to asymptomatic adolescents during running.

METHODS

Twenty-six adolescents with patellofemoral pain (14 male, 12 female, mean ± standard deviation age: 14.4 ± 1.7 years) and 24 asymptomatic adolescents (13 male, 11 female, mean ± standard deviation age: 14.1 ± 1.6 years) participated in this cross-sectional study. Participants ran on an instrumented treadmill in a traditional athletic shoe while kinematic and kinetic data were collected. Peak knee flexion angle, peak internal knee extension moment, and cumulative and peak patellofemoral joint force were compared between groups using a one-way analysis of covariance (α = 0.05). The mean difference (MD) with 95% confidence intervals [95% CI] and standardised mean differences (SMD) were calculated to express the magnitude of difference between groups.

RESULTS

Peak patellofemoral joint force [MD = -0.22 (-0.33, 0.77) N/kg] and cumulative patellofemoral joint force [MD = -6.26 (-37.47, 50.00) Bw.s/km] were not different between adolescents with patellofemoral pain and asymptomatic adolescents. Peak knee flexion [MD = 0.19 (-2.72, 2.33) deg] and knee extension moment [MD = -0.11 (-0.07, 0.29) Nm/kg] were also not different between groups.

DISCUSSION: Greater patellofemoral joint forces during running are not evident in adolescents with patellofemoral pain when compared to asymptomatic adolescents.