This study aims to (1) assess the inter-limb asymmetry in hip, knee, and ankle strength and countermovement jump (CMJ) performance among adolescent basketball players and (2) examine the relationship between inter-limb asymmetry and CMJ performance. Moreover, 30 adolescent basketball players (15 boys and 15 girls) aged 14 to 15 years participated in this study. The strength of the lower limb joints was measured using an isokinetic dynamometer at a speed of 60 degrees per second. Three maximal CMJs were performed, and the highest jump was used for the final analysis. The subjects were median-split into high-asymmetry (n = 15) and low-asymmetry (n = 15) groups based on the calculated strength asymmetry scores. The asymmetry scores were calculated using the formula: (dominant–non-dominant)/dominant* 100%. The inter-limb asymmetry data ranged from 12.2% to 21.6%. A Spearman correlation analysis showed that only the inter-limb asymmetry of the ankle plantar flexor was significantly correlated with the CMJ heights (ρ = −0.56, p = 0.001). An independent t-test revealed no significant differences in strength asymmetry between boys and girls (all p > 0.05). The low-asymmetry group demonstrated significantly greater CMJ performance compared to the high-asymmetry group (ES = 1.11, 95% CI = 0.34–1.87, p = 0.007), indicating that inter-limb asymmetry of the ankle plantar flexor has a significant negative impact on CMJ performance. Coaches should focus on enhancing both the strength and symmetry of the ankle joints to improve athletic performance and prevent injuries in sports, where jumping is a common movement.

The aims of this study were to: 1) assess and compare the performance of lateral shuffles and lower limb jumps among pre-juvenile basketball players; and 2) calculate the asymmetry scores of these assessment methods and examine the association between their performance and existing inter-limb differences. Thirty-nine pre-juvenile basketball athletes (23 boys and 16 girls) performed the countermovement jump, the single leg countermovement jump, the single leg lateral jump, the single leg broad jump, and four shuffle tests (2 distances of 2.5 and 5 m × 2 in each direction) on separate days. Results revealed significant differences between the left and the right shuffle at distances of both 2.5 m (p < 0.05) and 5 m (p < 0.01), with inter-limb asymmetry scores ranging from 3.3 to 5.1%. There was no significant difference between the performance of the left and right legs in each single leg jump test, while the inter-limb asymmetry values ranged from 5.3 to 8.6%. Correlation analysis showed there were no correlations among the inter-limb asymmetry, shuffle asymmetry and performance, while the right single leg countermovement jump performance was significantly correlated with shuffle performance (all p < 0.001). Shuffle performance in different directions exhibited significant differences which were unrelated to inter-limb asymmetry, demonstrating the task-specific nature of asymmetry and natural variability seen in lateral movements of pre-juvenile basketball players. Practitioners are advised to use a diversified approach to assess asymmetry. These findings have implications for injury prevention and performance enhancement.