The long and the short of sports success
– it’s all in the hands

Jordan Tomkinson and his digit ratio. HEALTH
Jordan Tomkinson and his digit ratio.

The difference in length between your index finger and your ring finger – known as your digit ratio - could be an indicator of sporting prowess, according to new research by a UniSA senior lecturer.

Research in the United States by UniSA’s Dr Grant Tomkinson and his son Jordan, analysed the digit ratio of adolescent boys and its relationship to their sporting prowess.

Their results show that the lower the difference in height between the two fingers, the better sportsperson someone is likely to be, with handgrip strength an important indicator.

Dr Tomkinson says the ring finger in males is typically longer than the index finger, whereas the fingers are about the same length in females.

“There is some indirect evidence that this digit ratio of the length of the fingers is determined during early fetal development by testosterone – the more testosterone the fetus produces, the longer the ring finger, so the smaller the digit ratio,” Dr Tomkinson says.

“Testosterone is the natural steroid hormone that enhances sport, athletic and fitness test performance. In general, people with smaller digit ratios are better athletes.

“For example, people with lower digit ratios tend to be better professional soccer players, basketball players, middle-distance runners, sprinters, fencers, sumo wrestlers, rugby players and rowers.

“Our study shows that boys with lower digit ratios have better handgrip strength and this is irrespective of their age or body size.”

The study is the first to look at the relationship between the digit ratio and muscular strength in adolescent boys and found that the relationship likely reflects the long-term benefits of prenatal testosterone, especially its effect on growth and development of the musculoskeletal system.

During the study, 57 adolescent males from Sacred Heart School (East Grand Forks, USA) aged 13-18 participated by recording their age, digit ratio, body mass and right handgrip strength.

Given that muscular strength is an important determinant in success in many youth sports and athletic events, the findings suggest the digit ratio may predict performance in youth sports and athletic events requiring high strength.

With muscular strength also an important indicator of good health, the study also suggested adolescent boys with lower digit ratios have better general health.

The research paper Digit ratio (2D:4D) and muscular strength in adolescent boys by Jordan M. Tomkinson and Grant R. Tomkinson has been published in the Journal of Early Human Development.