Acute Prolonged Hamstrings Vibration Reduces Limb Stiffness Following Anterior Cruciate Ligament Reconstruction...

Area of Science:

• Biomechanics
• Orthopedic Surgery
• Rehabilitation Medicine

Background:

• Impaired quadriceps function after anterior cruciate ligament reconstruction (ACLR) leads to stiff limb loading, increasing knee osteoarthritis risk.
• Increased hamstrings/quadriceps co-activation in ACLR patients contributes to impaired quadriceps function.
• Prolonged hamstrings vibration may overcome reciprocal inhibition, enhancing quadriceps activation and potentially reducing limb stiffness.

Purpose of the Study:

• To investigate the effects of prolonged hamstrings vibration on limb loading biomechanics in individuals with ACLR.
• To determine if hamstrings vibration can reduce limb stiffness and improve loading strategies post-ACLR.
• To assess the impact of hamstrings vibration on knee biomechanics during a drop-landing task.

Main Methods:

• Fourteen participants with unilateral ACLR and 14 healthy controls performed a single-leg drop-landing task.
• Biomechanical parameters including limb stiffness, peak vertical ground reaction force, loading rate, knee excursion, and knee extension moment were measured.
• Measurements were taken before and after a 20-minute hamstrings vibration intervention.

Main Results:

• Pre-vibration, ACLR group exhibited significantly greater limb stiffness, peak vertical ground reaction force, and loading rate compared to controls.
• ACLR group showed significantly less knee excursion and knee extension moment pre-vibration.
• Post-vibration, the ACLR group demonstrated significantly reduced limb stiffness, peak vertical ground reaction force, and loading rate, with increased knee excursion and knee extension moment.

Conclusions:

• Prolonged hamstrings vibration effectively mitigated stiff limb loading strategies in individuals with ACLR.
• This intervention shows potential for reducing the risk of knee osteoarthritis following ACLR.
• Hamstrings vibration may serve as a valuable adjunct therapy in ACLR rehabilitation programs.