Qualification-related differences in ankle kinematics during the right-hand uppercut in competitive boxers

Abstract

Background and Study Aim. Punching performance in boxing depends on coordinated kinetic chain interactions between the lower and upper limbs. During the execution of the uppercut, the ankle joint contributes to body stabilization and force transfer across movement phases. Although various biomechanical parameters are used to analyze punching technique, the influence of qualification level on ankle joint kinematics during the uppercut remains a subject of practical interest. This study aimed to examine how qualification level influences ankle kinematics during the right-hand uppercut in male boxers of high sport qualification. Materials and Methods. A total of 36 male boxers were stratified into two qualification groups: Masters of Sport (highly qualified boxers) (n = 18) and Candidate Masters of Sport (advanced-level boxers) (n = 18). Participants performed maximal-effort right-hand uppercuts under controlled laboratory conditions. Ankle joint kinematics were assessed using three-dimensional motion analysis (3DMA). The analysis included minimum and maximum joint angles, range of motion (ROM), maximum angular velocity, toe-off angle, mid-support angle, and propulsion distance. Between-group differences were evaluated using bias-corrected Hedges' g with 95% confidence intervals (CI). Effect magnitude and η² were calculated to estimate the practical relevance of the results. Results. The most significant standardized difference was observed in the right ankle mid-support angle (g = 0.76, 95% CI 0.08 to 1.44; η² = 0.14). It was followed by the right ankle minimum angle (g = 0.72, 95% CI 0.04 to 1.40; η² = 0.13). Moderate effects were found in the left ankle ROM (g = 0.67, 95% CI -0.00 to 1.34; η² = 0.11). Moderate but statistically uncertain effects were observed in the right ankle maximum angle and toe-off angle (g = 0.55; CIs crossing zero). In contrast, maximum angular velocity and propulsion distance demonstrated small standardized differences (g = 0.30–0.40), with confidence intervals overlapping the null value. Conclusions. Qualification level is primarily associated with differences in ankle joint positioning and stabilization during transitional support phases rather than with peak angular velocity output. The findings suggest that advanced technical proficiency in boxing may be characterized by refined sagittal-plane control and phase-specific joint modulation. Further studies integrating kinetic measurements and larger sample sizes are needed to confirm these biomechanical tendencies.