Abstract
Introduction: Inter-limb asymmetry refers to differences in performance or function between limbs, and 10-15% or more of it has been linked to a higher incidence of sports injuries. There is limited literature regarding inter-limb asymmetries in handball players. The aim of this study is to identify if semi-professional handball players have inter-limb asymmetries in their lower limbs and to see if there are differences in these asymmetries between players who had to reduce or cease their participation in handball activities due to lower limb injury and players who were able to participate fully without restrictions from lower limb injuries in the past 12 months.
Methods: This study is a case-control pilot study on 22 male 1st division handball players in Norway. The peak vertical ground reaction force of countermovement jumps (CMJ) and single-leg countermovement jumps (SLCMJ), hamstring/quadriceps peak torque ratio (H/Q ratio), and extension—and flexion peak torques were measured and used to examine inter-limb asymmetries. Participants were grouped based on how much lower limb injuries affected their participation in handball activities in the past 12 months, and this information was acquired from the questionnaire they filled out. Groups were full-participation (FP), reduced-participation (RP), and no-participation (NP).
Results: The whole sample showed significant differences in an H/Q ratio (p-value .008). The participants in the NP group showed a preference for their right leg during CMJ (80% of the participants) and SLCMJ (60% of the participants), while they preferred their left leg during flexion peak torque (80% of the participants). On the contrary, the FP group preferred their left leg in both jump tests (73% of the participants for both jump tests) and the right leg during flexion peak torque (64% of the participants). Additionally, 82% of participants in the FP group had a higher H/Q ratio in their right leg, but only 40% of the participants in the NP group favored the right leg.
Conclusion: The present study shows that semi-professional handball players have asymmetry in the lower limbs. The magnitude of asymmetry did not vary significantly between groups. However, the majority of participants in the FP and NP groups had different directions of asymmetry in 4 out of 5 variables compared to each other.