Hip and ankle kinematics are the most important predictors of knee joint loading during bicycling

ObjectivesTo assess the effect of ankle, knee, and hip kinematics on patellofemoral tibiofemoral joint reaction forces (JRF) during bicycling. Secondarily, to if sex, horizontal saddle position, or crank arm length were related JRFs, after accounting for kinematics.DesignExperimental cross-sectional study.MethodsForty healthy adults (mean (SD); 28.6 (7.2) years, 24.2 (2.6) kg/m2, 17 women) bicycled under 18 bicycling positions. One position used commercial guidelines randomly deviated from commercial. Resultant as well compressive shear JRFs calculated. Linear mixed-effects models with a random intercept leg-nested-in-participant used.ResultsPatellofemoral resultant most sensitive all (i.e., sensitivity was defined slope single predictor models); least minimum knee flexion. Tibiofemoral compression predicted by flexion maximum ankle dorsiflexion (R2 = 0.90). 0.86) JRF 0.90) flexion, dorsiflexion, interaction between Adding sex factor improved fit models. This sex-effect driven differences in cycling intensity, reflected tangential force. Horizontal not JRFs.ConclusionsOptimizing should be primary goal bicycle-fit. current gold standard assessing bicycle-fit, Bicycle-fit is particular importance those working at high intensities.