Energy dissipation differs between females with and without chronic ankle instability.

Area of Science:

• Biomechanics
• Sports Medicine
• Rehabilitation Science

Background:

• Chronic ankle instability (CAI) is linked to altered energy absorption during movement.
• Previous research has not directly compared energy dissipation patterns in CAI to individuals who have recovered from lateral ankle sprains (LAS) and are considered copers.
• Understanding these differences is crucial for developing targeted interventions for CAI.

Purpose of the Study:

• To investigate differences in relative sagittal plane energy dissipation during single-leg landings between female participants with CAI and LAS copers.
• To identify which joints (ankle, knee, hip, proximal) contribute differently to energy dissipation in these two groups.

Main Methods:

• 33 female participants (17 CAI, 16 LAS copers) performed single-leg landings.
• Sagittal plane kinematics and joint moments were recorded for the ankle, knee, and hip.
• Relative energy dissipation at each joint was calculated at 50, 100, 150, and 200 ms post-landing.
• Independent t-tests and Cohen's d effect sizes were used for statistical comparisons.

Main Results:

• The CAI group exhibited significantly lower relative energy dissipation from the ankle at 50, 100, and 150 ms post-landing compared to LAS copers.
• Conversely, the CAI group showed a greater contribution from the hip and proximal joints (knee and hip combined) to energy dissipation through 150 ms.
• These differences were statistically significant and indicated moderate to large effect sizes.

Conclusions:

• Females with CAI demonstrate a distinct energy dissipation strategy during single-leg landings, relying less on the ankle joint.
• This altered strategy involves increased reliance on proximal joints, particularly the hip.
• Therapeutic interventions for CAI should consider exercises aimed at improving ankle energy dissipation and potentially modifying proximal joint compensation patterns.