The associations between digit ratio (2D:4D and right – left 2D:4D), maximal oxygen consumption and ventilatory thresholds in professional male football players

Abstract

Introduction
Digit ratio (2D:4D: the relative length of the 2nd and 4th digit) is thought to be a negative correlate of prenatal testosterone. The 2D:4D is related to oxygen metabolism, but the precise nature of this relationship is unclear. The purpose of the present study was to consider associations between digit ratios (right 2D:4D, left 2D:4D, right–left 2D:4D [Dr-l]) and VO2max and ventilatory thresholds (VT1 and VT2).

Methods
One hundred and thirty-three Caucasian (n = 133) professional football players competing in Cyprus participated in the study. Players underwent anthropometric measurements, and digit lengths were measured from hand scans. They also completed an incremental cardiopulmonary test to exhaustion on a treadmill.

Results
There were negative correlations between digit ratios and VO2max (right 2D:4D, r = −.65; left 2D:4D r = −.37, both p < .0001; Dr-l r = −.30, p = .0005). There were no relationships between digit ratios and VT1. For VT2, there were negative relationships with digit ratios (right 2D:4D, r = −.43, p < .0001; left 2D:4D, r = −.21 and Dr-l, r = −.21, both p = .02). Digit ratios are negatively related to VO2max with large (right 2D:4D) and medium (left 2D:4D, Dr-l) effect sizes. For VT2, there were also negative correlations, which were medium (right 2D:4D) and small (left 2D:4D, Dr-l).

Conclusion
Our findings may help clarify the relationships between digit ratios and high-intensity actions for extended periods, which are dependent on efficient oxygen metabolism.