Evaldo Ribeiro1, Nick Neave2, Rosana Nogueiro Morais1, Liam Kilduff3, Suzan R Taylor4, Marina Butovskaya5, Bernhard Fink6, John T Manning7. 1. Department of Physiology, University of Paraná, Curitiba, Brazil. 2. Department of Psychology, Northumbria University, Newcastle-upon-Tyne, UK. 3. Applied Sports, Technology, Exercise and Medicine (A-STEM), Swansea University, Swansea, UK. 4. Sport and Exercise Sciences, Glyndwr University, Wrexham, UK. 5. Department of Cross-Cultural Psychology and Human Ethology, Institute of Ethnology and Anthropology, Russian Academy of Sciences and Russian State University of Humanities, Moscow, Russia. 6. Institute of Psychology, University of Göttingen, Göttingen, Germany. 7. Applied Sports, Technology, Exercise and Medicine (A-STEM), Swansea University, Swansea, UK. Electronic address: j.manning@swansea.ac.uk.
Abstract
BACKGROUND: Digit ratio (2D:4D) is a putative marker for prenatal testosterone and is correlated with performance in many sports. Low 2D:4D has been linked to strength but the evidence is mixed and strength is also influenced by mass, testosterone, and behavioural factors. It has been hypothesised that the 2D:4D-strength correlation may be strongest in challenge conditions when short-term changes occur in steroid hormones. AIMS: We tested this suggestion in men. STUDY DESIGN: We used a cross-over study design with a challenge (an aggressive video of rugby tackles) and control (a blank screen) condition. SUBJECTS: 89 healthy men. OUTCOME MEASURES: Finger lengths (2nd and 4th for both hands), hand-grip strength (HGS), testosterone (T), cortisol (C), aggression (Buss-Perry Aggression Questionnaire) and personality type (Ten Item Personality Measure). In both conditions participants provided saliva samples (for hormone assays). RESULTS: In the challenge condition there was a highly significant increase in HGS, and modest changes in T, physical aggression and emotional stability. HGS correlated negatively with left hand 2D:4D. In a multiple regression, left hand 2D:4D was negatively related to HGS and emotional stability was positively related to HGS. In the control condition HGS was not correlated with 2D:4D. In a multiple regression, BMI, physical aggression, and emotional stability were significantly related to HGS. CONCLUSIONS: 2D:4D is a negative correlate of strength in challenge situations. This finding may in part explain associations between 2D:4D and sports performance.
BACKGROUND: Digit ratio (2D:4D) is a putative marker for prenatal testosterone and is correlated with performance in many sports. Low 2D:4D has been linked to strength but the evidence is mixed and strength is also influenced by mass, testosterone, and behavioural factors. It has been hypothesised that the 2D:4D-strength correlation may be strongest in challenge conditions when short-term changes occur in steroid hormones. AIMS: We tested this suggestion in men. STUDY DESIGN: We used a cross-over study design with a challenge (an aggressive video of rugby tackles) and control (a blank screen) condition. SUBJECTS: 89 healthy men. OUTCOME MEASURES: Finger lengths (2nd and 4th for both hands), hand-grip strength (HGS), testosterone (T), cortisol (C), aggression (Buss-Perry Aggression Questionnaire) and personality type (Ten Item Personality Measure). In both conditions participants provided saliva samples (for hormone assays). RESULTS: In the challenge condition there was a highly significant increase in HGS, and modest changes in T, physical aggression and emotional stability. HGS correlated negatively with left hand 2D:4D. In a multiple regression, left hand 2D:4D was negatively related to HGS and emotional stability was positively related to HGS. In the control condition HGS was not correlated with 2D:4D. In a multiple regression, BMI, physical aggression, and emotional stability were significantly related to HGS. CONCLUSIONS: 2D:4D is a negative correlate of strength in challenge situations. This finding may in part explain associations between 2D:4D and sports performance.
Authors: Jakub Grzegorz Adamczyk; Krzysztof Safranow; Antoni Kazimierz Gajewski; Dariusz Boguszewski; Henryk Sozański; Ireneusz Sołtyszewski; Beata Pepłońska; Paweł Cięszczyk; Marcin Siewierski; Cezary Żekanowski Journal: J Hum Kinet Date: 2021-03-31 Impact factor: 2.923