Motor Performance and 2D:4D Digit Ratio in Male Cross-Country Skiers

Abstract

The second-to-fourth digit ratio (2D:4D) is considered a biomarker of prenatal androgen exposure and has been linked to various physical and athletic attributes. However, evidence regarding its relationship with sport-specific motor performance, particularly in endurance-based disciplines, remains inconclusive. The aim of this study is to investigate the relationship between the right-hand 2D:4D digit ratio and selected motor performance parameters-including strength, speed, agility, and endurance-in male cross-country skiers. This cross-sectional study investigated the associations between the 2D:4D digit ratio and multiple performance parameters in male cross-country skiers (n = 15). Anthropometric measurements, 2D:4D ratios (right hand), and performance tests-including 20 m sprint, Illinois agility test, vertical jump, sit-ups, handgrip, and back strength-were conducted under standardized conditions. Pearson correlation analyses were used to examine associations between digit ratio and performance variables. Negative but non-significant correlations were found between the 2D:4D ratio and sprint as well as agility performance, suggesting that lower ratios may be associated with faster and more agile movement patterns. Conversely, a significant positive relationship was observed between 2D:4D and back strength, while other strength measures (handgrip, vertical jump) showed weak positive trends. These findings indicate that in cross-country skiing, which emphasizes endurance, coordination, and trunk stabilization, training-induced neuromuscular adaptations may outweigh the effects of prenatal androgen exposure. The results suggest that the 2D:4D ratio reflects an interaction between biological predisposition and sport-specific training adaptation, rather than serving as an independent determinant of performance. While a lower 2D:4D ratio appears advantageous for speed and agility, the relationship between digit ratio and strength performance may vary depending on the technical and endurance demands of the sport. Future longitudinal studies incorporating hormonal profiling and bilateral digit measurements are needed to clarify whether the 2D:4D ratio can function as a practical biomarker for talent identification and performance monitoring in elite athletes.