Effect of Alpine ski boot cuff release on knee joint force during the backward fall

Area of Science:

• Biomechanics
• Sports Medicine
• Orthopedic Engineering

Background:

• Modern rigid alpine ski boots are linked to increased severe knee joint injuries.
• A new ski boot design features a rear spoiler that releases under posterior force.

Purpose of the Study:

• To investigate the biomechanical effects of a novel ski boot design on knee joint forces.
• To determine if the rear spoiler release mechanism influences forces associated with anterior cruciate ligament injuries.

Main Methods:

• Subjects performed backward falls to trigger ski boot cuff release.
• Motion analysis and kinetic measures were used to estimate knee joint forces.
• A link-segment model was employed to analyze shear and compressive forces.

Main Results:

• The rear spoiler opening significantly reduced anterior cruciate ligament-directed shear force.
• A concurrent increase in compressive force at the knee joint was observed.
• These force changes occurred over a very brief time interval.

Conclusions:

• The novel ski boot design may offer knee protection by reducing anterior cruciate ligament shear forces.
• Both increased compressive force and reduced shear force are potentially protective knee mechanisms.
• Further research is needed to confirm the long-term influence on knee injury prevention.