Effect of dynamic stability on a step task in ACL deficient individuals

Area of Science:

• Biomechanics
• Orthopedics
• Sports Medicine

Background:

• Anterior cruciate ligament (ACL) deficiency significantly impacts knee function, particularly during activities like stair negotiation.
• Individuals with ACL deficiency exhibit varied functional capabilities, broadly categorized as 'copers' and 'non-copers'.

Purpose of the Study:

• To compare movement and muscle activity patterns during stair ascent and descent in ACL-deficient individuals (copers and non-copers) and uninjured controls.
• To determine if functional classification influences biomechanical adaptations in ACL-deficient individuals.

Main Methods:

• Collected sagittal plane kinematic and kinetic data (hip, knee, ankle) and electromyographic data (vastus lateralis, hamstrings, gastrocnemius, soleus).
• Analyzed data from ACL-deficient 'copers' (high-level sport participation, no instability), 'non-copers' (instability in daily activities), and uninjured subjects during stair negotiation over a 26 cm step.

Main Results:

• Both coper and non-coper groups displayed altered movement patterns during stair ascent and descent compared to controls.
• Non-copers showed significantly different movement patterns on their involved limb during the weight-accepting phase of stair descent compared to controls.
• Functional classification revealed more distinct differences between non-copers and copers than comparing ACL-deficient groups to controls alone.

Conclusions:

• Functional classification is crucial for understanding biomechanical differences in ACL deficiency.
• Copers demonstrate movement patterns more similar to uninjured individuals, suggesting effective compensation strategies.
• Non-copers exhibit distinct kinematic and kinetic deficits, particularly during the critical weight-bearing phase of stair descent.