Interlimb Asymmetries: The Need for an Individual Approach to Data Analysis

Area of Science:

• Sports science
• Biomechanics
• Human movement analysis

Background:

• Interlimb asymmetries are common in athletes.
• The consistency of limb dominance for asymmetries across different tests is not well-established.
• Understanding this consistency is crucial for effective training program design.

Purpose of the Study:

• To investigate whether interlimb asymmetries consistently favor the same limb across various unilateral strength and jumping tests.
• To compare asymmetry patterns between different types of movements (isometric vs. dynamic).
• To assess the agreement of asymmetry measurements across different tests.

Main Methods:

• Twenty-eight recreational athletes performed unilateral isometric squats, single-leg countermovement jumps, and single-leg broad jumps.
• Peak force, eccentric impulse, and concentric impulse were measured.
• Asymmetries were calculated and compared across tests using the Kappa coefficient for agreement.

Main Results:

• Mean asymmetries were generally low (≤-5.3%).
• Jump tests showed left-limb dominance, while isometric squats favored the right limb.
• Individual asymmetry magnitudes varied significantly, and agreement across tests was mostly slight to substantial, except for concentric impulse in jump tests.

Conclusions:

• Interlimb asymmetries do not consistently favor the same limb across different tests.
• An individualized approach to analyzing and reporting asymmetries is necessary.
• This personalized analysis can inform the development of targeted training interventions to reduce asymmetries.