Whether running for personal goals, charity, or ticking off a bucket list item, marathons attract amateur and recreational runners globally. A study by the University of South Australia and UND suggests that a person’s potential for marathon running might be revealed through examining their hands.
The study, published in “Early Human Development,” is a meta-analysis of 22 studies involving 5,293 participants from 12 countries. It found that individuals with a lower digit ratio—where the ring finger is longer than the index finger—tend to have better cardiorespiratory fitness. This trait is considered a biomarker for exercise tolerance and endurance performance.
Lead researcher Professor Grant Tomkinson from UniSA, who has previously taught at UND, explained that digit ratio serves as an indicator of prenatal androgen exposure, particularly testosterone. “A lower digit ratio…indicates greater testosterone exposure in the womb, which is associated with better physical fitness,” said Tomkinson. He emphasized that prenatal hormone environments likely influence health outcomes throughout life.
The study also involved Samantha Peterson from UND and two other researchers: Professor Marilyn Klug and kinesiology alumnus Matthew Russell. Peterson expressed interest in the study’s focus on prenatal testosterone’s impact on finger length. “Being able to take something so simple as looking down at your hands and use it as an indication of cardiac fitness is really amazing,” she noted.
Data were analyzed from 11 studies across seven countries (China, Spain, Turkey, Greece, Poland, Portugal, and India), assessing 1,061 children aged between 6 and 18 years using the 20-meter shuttle run test to measure aerobic fitness.
Tomkinson stated that while the link between digit ratio and cardiorespiratory fitness is moderate, it offers a simple screening tool for identifying children with cardiovascular potential. This could guide targeted fitness interventions since aerobic fitness in youth indicates future health prospects.
Peterson’s collaboration with Tomkinson began during her doctoral studies at UND when she took his statistics class. Their joint efforts on this research have provided insights into potential non-invasive pre-screening methods for endurance sports capabilities and long-term health risks.
