The Impact of Postural Parameters on Upper Limb Performance: Interaction With Training Years and Gender Covariate.

Context: This study investigates the main effects of axial spine posture, gender (as a dummy variable), and training years, along with the interaction of training years with postural parameters, on upper-extremity functional performance in overhead athletes.

Design: Cross-sectional study.

Methods: A total of 135 athletes participated in the study, including 57 healthy male and 78 female athletes. Photographic posture analysis and functional performance tests were utilized to assess static posture parameters and the athletic performance respectively. Multiple linear regression analysis was conducted to explore statistically significant variables and estimate their coefficients, examining the relationships among static posture alignment variables, years of training, their interaction with postural variables, and gender as a control variable, with performance metrics as the outcome.

Results: The findings revealed significant effect of gender in Upper Quarter Y Balance Test Dominant (B = 4.36, P < .05), Closed Kinetic Chain Upper-Extremity Stability Test (B = 2.77, P < .05), and both Unilateral Seated Shot-Put Test Dominant (B = 173.46, P < .05) and nondominant sides (B = 148.00, P < .05), with males outperforming females. Nondominant C7 tragus alignment interacting with training years significantly predicted Upper Quarter Y Balance Test Dominant (B = 0.20, P < .01) and Unilateral Seated Shot-Put Test Dominant (B = 0.98, P < .05) and Nondominant (B = 0.89, P < .05) performance, while thoracic kyphosis interacting with training years significantly affected the Unilateral Seated Shot-Put Test Nondominant side (B = -0.24, P < .05).

Conclusions: Gender-related differences in lumbar lordosis and thoracic kyphosis suggest biomechanical variations impacting postural control and injury risk. Training-induced spinal adaptations highlight the role of sport-specific loading. These findings support the need for personalized training programs tailored to gender and training history to optimize performance and reduce injury risk, with future research recommended to include dynamic postural assessments for a deeper understanding of posture-performance relationships.