Increased Q-Factor increases frontal-plane knee joint loading in stationary cycling

Area of Science:

• Biomechanics
• Sports Science
• Orthopedics

Background:

• Q-Factor (inter-pedal width) in cycling is analogous to step-width in gait.
• Increased step-width reduces peak knee abduction moment (KAbM).
• Biomechanical effects of varying QF in cycling remain understudied.

Purpose of the Study:

• To investigate the biomechanical effects of increased Q-Factor (QF) on knee joint loading during cycling.
• To examine these effects across different workrates in healthy participants.

Main Methods:

• 16 healthy participants (8 males, 8 females) were recruited.
• Motion capture and instrumented pedals collected 3D kinematic and pedal reaction force data.
• Testing involved 4 QF conditions and 3 workrates (80W, 120W, 160W).

Main Results:

• Increased QF significantly elevated peak KAbM by 47-56% across workrates.
• Mediolateral pedal reaction force and frontal-plane knee motion decreased with higher QF.
• No significant changes were found in vertical pedal force or knee extension moments.

Conclusions:

• Higher QF increases peak KAbM, indicating greater medial compartment knee loading.
• Modulating QF may impact frontal-plane joint loading during stationary cycling.
• Considerations for exercise and rehabilitation protocols are suggested.