Is the 10% Asymmetry Threshold Important in Team Handball? Interlimb Asymmetry and Threshold-Based Performance...

Area of Science:

• Sports Science
• Biomechanics
• Athletic Performance

Background:

• Unilateral functional performance asymmetry can impact elite athletes' performance and injury risk.
• Understanding asymmetry ratios in handball players informs training and monitoring strategies.

Purpose of the Study:

• To investigate the relationship between asymmetry ratios from unilateral functional tests and performance in elite male handball players.
• To determine the effect of a 10% asymmetry threshold on performance outcomes.

Main Methods:

• Cross-sectional study involving 41 elite male handball players.
• Lower extremity strength assessed via vertical jump (VJ), counter movement jump (CMJ), and single-leg hop tests (SLHTs).
• Dynamic balance measured using the Y balance test (YBT); players classified by a 10% asymmetry threshold.

Main Results:

• Moderate positive correlations found between jump test asymmetry and dynamic balance.
• Significant left-right differences observed in VJ, CMJ, single hop for distance (SH), triple hop (TH), 90° medial rotation hop (MRH), and anterior YBT scores.
• Athletes with <10% asymmetry outperformed those with >10% across all tests, with large effect sizes for key jump and balance measures.

Conclusions:

• A 10% strength asymmetry ratio is a critical reference point for elite male handball players.
• Systematic monitoring of asymmetry is vital for both injury prevention and performance optimization.
• Correcting strength asymmetry below 10% can enhance performance and reduce injury risk in elite handball athletes.