Author(s): ATES, B., UZUNER, K., ÖLMEZ, C. , Institution: ORDU ÜNIVERSITESI, Country: TURKEY, Abstract-ID: 1015

INTRODUCTION:
Maximal soccer kicking performance is a complex biomechanical outcome generated through coordinated lower-extremity kinetic-chain interactions. Although proximal joint strength has traditionally been emphasized, distal joint capacity—particularly ankle strength—may play a critical role in regulating impact mechanics and effective energy transfer to the ball. This study aimed to examine the relationships between kicking ball speed and ankle plantar flexion and dorsiflexion isometric strength variables, as well as composite ankle strength indices (ASI), in trained soccer players.
METHODS:
Twenty-one male soccer players (age: 20.62±2.73 years; height: 179.19±3.96 cm; body mass: 76.33±9.03 kg) participated in this cross-sectional study. Maximal kicking ball speed was measured using a radar device, and the highest value obtained from three trials was retained for analysis (92.52±9.02 km·h⁻¹). Isometric peak torque values for ankle plantar flexion and dorsiflexion were assessed using an isokinetic dynamometer and normalized to body mass. Standardized torque values were combined to calculate dominant and non-dominant ankle strength indices (ASI). Pearson correlation analysis was used to determine the relationships between kicking ball speed and mechanical variables.
RESULTS:
Kicking ball speed demonstrated a significant positive correlation with dominant dorsiflexion isometric strength (r=0.510, p=0.018), whereas plantar flexion strength variables were not significantly associated with performance (p>0.05). Composite ankle strength indices showed stronger relationships with ball speed. Significant correlations were observed between ball speed and the dominant ASI (r=0.634, p=0.002) as well as the non-dominant ASI (r=0.514, p=0.017). Gastrocnemius EMG composite activation values and maximal voluntary contraction (MVC) force measures were not significantly related to kicking performance.
CONCLUSION:
Because strength assessments were performed under isometric conditions, the observed relationships likely reflect ankle joint stabilization capacity and the neuromechanical potential to regulate joint stiffness during ball impact rather than dynamic power production alone. The findings indicate that maximal kicking performance is more closely associated with the combined isometric capacity of plantar flexor and dorsiflexor muscle groups than with isolated single-direction strength measures. These results suggest that training interventions targeting both plantar flexion and dorsiflexion strength within stability-oriented strength programs may improve maximal kicking performance.