Effects of Saddle Heights on Patellofemoral Joint Force and Stress during Cycling

Objective:Prior research indicates that overuse of forces and great angle movements at the knee joints during cycling may lead to a high risk of knee injury, including patellofemoral pain.The purpose of this study was to evaluate the effects of different saddle heights on patellofemoral joint force and stress during cycling.Methods:20 healthy subjects, serving as self-control, performed a cycling task with the saddle set at four different heights (Low, Medium, High, and Preferred) .Data across the four different saddle heights were collected by using 3 D Kinematics and pedal reaction force.The dependent variables were peak quadriceps, patellofemoral joint force, joint stress, and angle at knee joints.Results:Resultsfrom the MANOVA test showed an overall significant difference attributable to saddle height (P<0.05) , indicated that, compared with High, Medium, and Preferred heights, performance at the Low saddle height showed greater peak quadriceps force, peak patellofemoral joint force, and peak patellofemoral joint stress (P<0.05) .In addition, compared with High, Medium, and Preferred heights, the instant angle at the knee joint during the Low height performance was shown to be greatest at the peak of the patellofemoral joint force (P<0.05) .No differences were observed, however, for the angle at the knee joint for the joint stress.Conclusion:Comparing to higher saddle positions during cycling, a low saddle height produced greater peak quadriceps force, patellofemoral joint force, patellofemoral joint stress, and greater knee angle shown at the peak of the patellofemoral joint force.These results suggest that cycling with a low saddle height may have a negative impact on patellofemoral joints.