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Kozieł S, Konarski JM, Konarska A, Huechert J, Ignasiak Z, Chakraborty R. The change in handgrip strength, after physical exercise, is moderated by digit ratio (2D:4D): A study among the young adults in Poland. Am J Hum Biol 2024:e24078. [PMID: 38576074 DOI: 10.1002/ajhb.24078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 03/18/2024] [Accepted: 03/24/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND The digit ratio (2D:4D), the ratio of the lengths of second (2D) to the fourth (4D) fingers, is a proxy indicator of prenatal androgen exposure. On average, males display lower 2D:4D than females. Previous studies have shown that lower 2D:4D ratios were associated with better sports and physical abilities. AIM To assess whether a challenge condition, imposed by intense exercise, could increase handgrip strength (HGS) associated with 2D:4D. METHODS This cross-sectional experimental study included 90 healthy young Polish adults (40 males, 50 females). They underwent intense physical exercise, before (7 days) and after which they were measured for HGS and 2D:4D. Height and weight were also measured. Analyses of Covariance were employed to delineate associations. RESULTS 2D:4D had significant predictive effects on the differences in HGS (DHGS) measured in two occasions, without and after, physical exercises. The lower was the 2D:4D, the higher the DHGS, particularly, for the left hand. CONCLUSION The results reconfirmed that the link between prenatal testosterone exposure (indicated by 2D:4D) and physical strength depends on the context, such as a challenged condition.
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Affiliation(s)
- Sławomir Kozieł
- Department of Anthropology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Jan M Konarski
- Department of Theory of Sports, Poznań University of Physical Education, Poznań, Poland
| | - Agata Konarska
- Department of Physiotherapy, Stanisław Staszic University of Applied Science, Piła, Poland
| | - Joanna Huechert
- Department of Anthropology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Zofia Ignasiak
- Faculty of Physical Education, University School of Physical Education in Wroclaw, Wroclaw, Poland
| | - Raja Chakraborty
- Department of Anthropology and Tribal Studies, Sidho-Kanho-Birsha University, Purulia, West Bengal, India
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Ribeiro E, Neave N, Marsili BK, Figueiredo ECG, Martino-Andrade AJ, de Moraes RN. Prenatal androgenization (2D:4D) predictions of tennis match-play success in junior players: A search for physiological explanations. Am J Hum Biol 2024; 36:e23979. [PMID: 37602536 DOI: 10.1002/ajhb.23979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023] Open
Abstract
AIM This study aims to investigate the possible association between digit ratio (2D:4D) and match-play success (MPS) in junior tennis players. In addition, we consider the possible explanatory pathways of these associations in relation to psychological, strength, power, and hormonal parameters. METHODS We performed a cross-sectional study, with a sample comprised of 64 male junior tennis players (11-18 years old). Digit ratio was calculated from direct finger measurements. In addition, we measured the ratio of wins by number of matches played in 5 years of official competition (MPS), handgrip strength (HGS), standing long jump (SLJ), training (in weekly hours), and expertise (number of years in official competition). Salivary testosterone and cortisol levels were measured before and after physical "challenge" tests. RESULTS The 2D:4D correlated negatively with HGS and SLJ. MPS was also negatively associated with 2D:4D, but was positively correlated to HGS, expertise, training, and self-confidence (SC). Multiple linear regression showed 2D:4D and expertise were associated with MPS (43%-54%). None of the physical, or hormonal variables tested explained the links between 2D:4D and MPS. CONCLUSION Therefore, the specific fitness components influenced by prenatal androgenization that moderate sports success remain unknown. Future studies should explore the interaction of 2D:4D, with tennis exercises as a challenge to induce hormonal change, the effect of pubertal stage, and the influence of aerobic endurance in determining MPS.
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Affiliation(s)
- Evaldo Ribeiro
- Litoral Sector, Federal University of Paraná, Matinhos, Brazil
- Department of Physiology, Federal University of Paraná, Curitiba, Brazil
| | - Nick Neave
- Department of Psychology, Northumbria University, Newcastle-upon-Tyne, UK
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Crewther BT, Pastuszak A, Sadowska D, Górski M, Cook CJ. The digit ratio (2D:4D) and testosterone co-predict vertical jump performance in athletic boys: Evidence of organizational and activational effects of testosterone on physical fitness. Physiol Behav 2022; 251:113816. [PMID: 35443197 DOI: 10.1016/j.physbeh.2022.113816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/29/2022] [Accepted: 04/14/2022] [Indexed: 11/28/2022]
Abstract
The digit ratio (2D:4D) is a negative correlate of boy's physical fitness, and thought to arise from organizational effects of prenatal testosterone on different bodily systems. During human ontogeny, activational effects of testosterone on body size and strength offers another pathway to physical fitness. We tested these hypotheses by examining the organizational and activational effects of testosterone on vertical jump performance in athletic boys. Using a cross-sectional design, 173 boys (aged 9 to 18 years) were tested for standing height, body mass, body fat, fat-free mass, weekly training activity, training history, salivary testosterone and cortisol, R2D:4D, L2D:4D, and right-left 2D:4D (Dr-1), and vertical height in 3 different countermovement jump (CMJ) tests. A generalized additive model was employed to delineate age-related trajectories and predict CMJ performance. Our models yielded significant non-linear increases (or changes) in body size, current hormone concentration, training outcomes, and CMJ performance with chronological age. All 2D:4D measures were age invariant. The R2D:4D and testosterone were significant non-linear predictors of CMJ height with (R2 = 66.2%) or without (R2 = 54.3%) covariates, whereby a higher current testosterone concentration (up to a certain level) and a lower or higher R2D:4D were linked to better performance. The L2D:4D and Dr-1 had no predictive value. In conclusion, the R2D:4D and testosterone were co-predictors of CMJ height among athletic boys, with non-linear performance effects that differed in timing, tempo, and direction. Our findings confirm that testosterone can regulate a simple measure of boy's physical fitness through both an activational and organizational pathway.
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Affiliation(s)
- Blair T Crewther
- Institute of Sport - National Research Institute, Warsaw, Poland; School of Science and Technology, University of New England, Armidale, Australia.
| | - Anna Pastuszak
- Institute of Sport - National Research Institute, Warsaw, Poland
| | - Dorota Sadowska
- Institute of Sport - National Research Institute, Warsaw, Poland
| | - Michał Górski
- Institute of Sport - National Research Institute, Warsaw, Poland
| | - Christian J Cook
- School of Science and Technology, University of New England, Armidale, Australia; Hamlyn Centre, Imperial College, London, UK
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Pasanen BE, Tomkinson JM, Dufner TJ, Park CW, Fitzgerald JS, Tomkinson GR. The relationship between digit ratio (2D:4D) and muscular fitness: A systematic review and meta-analysis. Am J Hum Biol 2021; 34:e23657. [PMID: 34331730 DOI: 10.1002/ajhb.23657] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Digit ratio (2D:4D), a marker of prenatal testosterone exposure, is a weak negative correlate of sports/athletic/fitness performance. While numerous studies have examined the relationship between 2D:4D and physical fitness, there has never been a comprehensive study that has synthesized studies examining relationships between 2D:4D and muscular fitness. OBJECTIVES To systematically review and meta-analyze the relationship between 2D:4D and muscular fitness measured as handgrip strength (HGS). METHODS We systematically searched five electronic databases, reference lists, topical systematic reviews/meta-analyses, and personal libraries in November 2020. Peer-reviewed, cross-sectional studies that reported Pearson's correlation coefficients between objectively measured 2D:4D and HGS were included. We used random-effects meta-analysis to estimate the pooled correlation and the 95% confidence interval (95%CI), and moderator analyses to estimate the influence of sex and age. RESULTS Data from 22 studies, representing 5271 individuals from 11 countries ranging in (mean) age from 10.4 to 58.0 years, were included. Overall, there was a weak negative correlation between 2D:4D and HGS (r = -0.15, 95%CI = -0.20 to -0.09), indicating that individuals with low 2D:4Ds had high HGS. We found substantial heterogeneity between studies (Q = 123.4, p < .0001; I2 = 74%), but neither sex (Q = 0.003, p = .96) nor age (Q = 0.46, p = .50) significantly moderated the pooled correlation. CONCLUSIONS We found a weak negative relationship between 2D:4D and HGS, which showed substantial heterogeneity between studies, but was neither moderated by sex nor age. Our finding probably reflects both the long-term (organizational) and short-term (activational) benefits of testosterone.
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Affiliation(s)
- Brooke E Pasanen
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Jordan M Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Trevor J Dufner
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Chan Woong Park
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - John S Fitzgerald
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Grant R Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA.,Alliance for Research in Exercise, Nutrition and Activity (ARENA), Allied Health and Human Performance, University of South Australia, Adelaide, South Australia, Australia
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Klapprodt KL, Fitzgerald JS, Short SE, Manning JT, Tomkinson GR. Relationships between the digit ratio (2D:4D) and game-related statistics in professional and semi-professional male basketball players. Am J Hum Biol 2018; 30:e23182. [PMID: 30251289 DOI: 10.1002/ajhb.23182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/20/2018] [Accepted: 08/21/2018] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES The primary aim of this study was to examine relationships between digit ratio (2D:4D) and game-related statistics in professional and semi-professional male basketball players. The secondary aim was to quantify differences in mean 2D:4Ds between starting and reserve players. METHODS Using a cross-sectional design, 93 male basketball players from the professional Australian National Basketball League and the semi-professional South Australian Premier League were measured in-season for height, mass, and 2D:4D, with game-related statistics collected end-season. Linear relationships between right and left 2D:4Ds and game-related statistics were quantified using nonparametric partial correlations, and differences in mean 2D:4Ds between starting and reserve players were quantified using analysis of covariance (ANCOVA). All partial correlations and ANCOVAs were adjusted for playing experience, body size, and competitive standard. RESULTS 2D:4D was a weak to moderate negative correlate of points scored and assists-to-turnovers ratio, indicating that males with lower 2D:4Ds were generally better offensively as they recorded more points and assists relative to turnovers. The difference in mean 2D:4D between starting and reserve players was negligible. CONCLUSIONS 2D:4D was favorably correlated with open-skill sports performance, as evidenced by the better offensive statistics of male basketball players with lower 2D:4Ds. These results probably reflect the organizational benefits of prenatal testosterone and indicate that 2D:4D may be a useful complement to traditional physical, physiological, skill, and behavioral predictors of basketball success.
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Affiliation(s)
- Katelyn L Klapprodt
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota
| | - John S Fitzgerald
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota
| | - Sandra E Short
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota
| | - John T Manning
- Applied Sports, Technology, Exercise, and Medicine (A-STEM), Swansea University, Swansea, United Kingdom
| | - Grant R Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota.,Alliance for Research in Exercise, Nutrition and Activity (ARENA), School of Health Sciences and Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
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