Associated ACL risk factors differences during an unanticipated volleyball blocking movement

Area of Science:

• Sports Biomechanics
• Injury Prevention
• Kinesiology

Background:

• Volleyball blocking involves lateral arm and trunk movements.
• These movements during unanticipated blocks may increase anterior cruciate ligament (ACL) injury risk.
• Understanding biomechanical factors is crucial for injury prevention strategies.

Purpose of the Study:

• To compare ACL injury risk factors during unanticipated volleyball blocks.
• To investigate the effect of different arm positions (straight vs. tilted) on biomechanics.
• To identify specific risk factors associated with lateral trunk and arm tilt.

Main Methods:

• Synchronized kinematic and kinetic data were collected.
• Two conditions were compared: straight arms (S) and tilted arms/trunk (T).
• Student paired t-tests and effect size analysis were used.

Main Results:

• The tilted arm/trunk (T) condition significantly reduced knee flexion.
• T condition increased vertical ground reaction force (VGRF) at foot contact and first peak.
• T condition increased knee valgus moment at the first peak force.

Conclusions:

• Tilted arm and trunk positions during blocking increase ACL injury risk factors.
• Increased knee valgus and reduced flexion during landing are key risk indicators.
• Training should emphasize greater knee flexion and double-leg landings to mitigate injury risk.