Interlimb strength asymmetry is task-specific: moderate reliability but inconsistent limb dominance in multi-joint...

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Interlimb strength asymmetry is crucial for sports performance diagnostics.
• Reliability, velocity specificity, and limb dominance consistency in multi-joint dynamometry require further investigation.

Purpose of the Study:

• To assess the test-retest reliability of interlimb strength asymmetry using unilateral multi-joint isometric and isokinetic dynamometry.
• To determine the consistency of limb dominance across various knee angles and contraction velocities.

Main Methods:

• Twenty-five recreationally active adults performed unilateral leg press assessments.
• Tests included isometric (100°, 140°) and isokinetic (30, 600 mm·s⁻¹) conditions across two sessions.
• Interlimb strength asymmetry and directional limb dominance were calculated and analyzed for reliability and agreement.

Main Results:

• No significant systematic differences were found between test sessions.
• Relative reliability (ICC) was moderate to good (0.55-0.84), but absolute reliability showed substantial variability (SEM 2.9%-7.5%, MDC 8.1-20.8%).
• Limb dominance agreement was fair to substantial (kappa 0.24-0.65), with only 16% showing consistent dominance.

Conclusions:

• Interlimb strength asymmetry in multi-joint dynamometry is task-specific with considerable individual variability.
• Measurement error often exceeded clinical thresholds, necessitating cautious interpretation of asymmetry values.
• Avoid universal cutoffs for return-to-sport or performance decisions due to limited dominance stability.