Forecasting judo medal winners at the Olympic Games: an interaction of the International Judo Federation World Ranking List and the Elo System

Leandro Marques Guilheiro; Emerson Franchini

doi:10.18002/rama.v19i1.2414

Authors

Leandro Marques Guilheiro Institute for Pure and Applied Mathematics (IMPA) and Esporte Clube Pinheiros https://orcid.org/0009-0007-6134-5407
Emerson Franchini Martial Arts and Combat Sports Research Group, Sport Department, School of Physical Education and Sport, University of São Paulo https://orcid.org/0000-0002-0769-8398

DOI:

https://doi.org/10.18002/rama.v19i1.2414

Keywords:

Martial arts, combat sports, judo, performance prediction, Olympics, rating

Agencies:

The authors received no funding for this work

Abstract

The aim of this study was to verify which ranking list predicts Olympic results better: one created by Elo system, one using the International Judo Federation (IJF) World Ranking List (WRL), or another using the combination of both. The data utilized comprised the outcomes of 93,728 matches, encompassing 42,844 matches from the 2016 Rio Olympic Games cycle and 50,884 matches from the 2020 Tokyo Olympic Games cycle. These matches were held across 311 events, all of which contribute points to the IJF WRL. The data was sourced from https://judobase.ijf.org. A total of 8,142 male and 4,736 female judo athletes from all weight categories were analyzed. We employed two variables as proxies for athletes’ performance throughout the Olympic cycle: the positions in the IJF WRL and the ratings from the Elo System. A binary-response model was utilized. In this model, “success” denoted an athlete receiving a medal, while “failure” indicated otherwise. A combination of the WRL and Elo system better predicted Olympic performance of judo athletes. Additionally, for each rank position an athlete improved in the IJF WRL, there was an increased probability to win an Olympic medal of approximately 7.50%, while for each 10 Elo rating score improvement, the athlete increased the probability to win an Olympic medal in approximately 9.26%. When both systems were used together, the accuracy of the model was approximately 91%, with a sensitivity of nearly 68-69%, and a specificity close to 95%, for Rio de Janeiro and Tokyo editions isolated or grouped. Such information can serve as a valuable tool for national federations staff in selecting the most suitable athletes to participate in the Olympic judo competition, if both the WRL and an Elo rating system are used together.

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Author Biographies

Leandro Marques Guilheiro, Institute for Pure and Applied Mathematics (IMPA) and Esporte Clube Pinheiros

Leandro Marques Guilheiro (Brazil) is a Master’s student in Mathematics at the Institute for Pure and Applied Mathematics (MPA), where he investigates sports analytics. Currently, he serves as the head coach of the Esporte Clube Pinheiros judo team. Under his guidance, his athletes have won medals at the Olympic Games and World Championships across cadet, junior, and senior age categories. He holds a 6th dan in judo. As an athlete, he was a Junior World Champion, a double Olympic bronze medalist (Athens 2004 and Beijing 2008), and a double Senior World Championship medalist (silver in Tokyo 2010 and bronze in Paris 2011). E-mail: lguilheiro@hotmail.com

Emerson Franchini, Martial Arts and Combat Sports Research Group, Sport Department, School of Physical Education and Sport, University of São Paulo

Emerson Franchini (Brazil) is a full professor in the Department of Sport at the School of Physical Education and Sport, University of São Paulo, where he coordinates the Martial Arts and Combat Sports Research Group. He has been conducting research on combat sports since 1995, with a particular focus on judo. He holds a 2nd dan in judo and has worked as a consultant for international-level judo athletes, including the first author, who have won medals at the Olympic Games and World Championships. E-mail: efranchini@usp.br

References

Belmont Report. (1979). https://videocast.nih.gov/pdf/ohrp_belmont_report.pdf

Breviglieri, P. V., Possa, M. E. S., Campos, V. M., Humberstone, C., & Franchini, E. (2018). Judo world ranking lists and performance during cadet, junior and senior World Championships. Ido Movement for Culture. Journal of Martial Arts Anthropology, 18(2), 48–53. http://doi.org/10.14589/ido.18.2.7

Brunel, V. (2022). Seed advantage in sport competitions: the case of professional judo. Revista de Artes Marciales Asiáticas, 17(2), 108-118. http://doi10.18002/rama.v17i2.7047

Cox, D. R. (1958). The regression analysis of binary sequences (with discussion). Journal of Royal Statistical Society Series B, 20(2), 215–242. https://www.jstor.org/stable/2983890

Courel-Ibáñez J., Escobar-Molina R., & Franchini E. (2018). Does the ranking position predict the final combat outcome in senior and junior judo athletes? Revista de Artes Marciales Asiáticas, 13(2), 131-138. http://dx.doi.org/10.18002/rama.v13i2.5471

Daniel, L.F., & Daniel, R. (2013). Study regarding the prediction of medal winning in Olympic Games judo competitions. Journal of Physical Education and Sport, 13(3), 386-390. https://doi.org/10.7752/jpes.2013.03062

Elo, A. E. (1978). The rating of chess players, past and present. Arco.

Franchini, E., & Julio, U.F. (2015). The judo world ranking and the performances in the 2012 London Olympics. Asian Journal of Sport Medicine, 6(3), e24045. https://dx.doi.org/10.5812%2Fasjsm.24045

Franchini, E., Takito, M.Y., da Silva, R.M., Shiroma, S.A., Wicks, L., & Julio, U.F. (2017). Optimal interval for success in judo world-ranking competitions. International Journal of Sports Physiology and Performance, 12(5), 707-710. https://doi.org/10.1123/ijspp.2016-0375

Glickerman, M. (2016). The Glicko system. Retrieved from http://www.glicko.net/glicko/glicko.pdf

Guilheiro, L. M. (2020). Modelagem matemática do ranking mundial de judô e do desempenho relativo entre atletas de elite. [Monograph, Unisul, Palhoça, SC]. Supervisor: Christian Wagner.

Guilheiro, L. M., & Franchini, E. (2017). Be seeded or not be seeded? A study with Olympic judo athletes. Journal of Exercise Rehabilitation, 13(2), 148-152. https://doi.org/10.12965/jer.1734904.452

International Judo Federation (2024). Sport and Organisation Rules. www.ijf.org. 15 April 2024.

International Judo Federation (2024). Qualification System - Games of the XXXIII Olympiad - Paris 2024. https://78884ca60822a34fb0e6-082b8fd5551e97bc65e327988b444396.ssl.cf3.rackcdn.com/up/2023/12/2023-11-28_-_Olympic_Games_Par-1701595981.pdf 15 April 2024.

Langville, A. N., & Meyer, C. D. (2012). Who’s #1? The science of rating and ranking. Princeton University Press.

Minton, R.B. (2017). Sports math - an introductory course in the mathematics of sports science and sports analytics. CRC Press.

Neumann, C., & Kulik, L. (2020). Animal dominance hierarchies by Elo Rating [R]. Retrieved from https://github.com/gobbios/EloRating

Pelánek, R. (2016). Applications of the Elo rating system in adaptive educational systems. Computers and Education, 98 ,169-179. https://doi.org/10.1016/j.compedu.2016.03.017

Santos, D. F. C., Kons, R. L., Lopes-Silva, J. P., Agostinho, M. F., Detanico, D., Takito, M. Y., & Franchini, E. (2023). Participation in the International Judo Federation World Tour competitions and performance in Tokyo Olympic Games. Frontiers in Sports and Active Living, 27(5), 1216002. https://doi.org/10.3389/fspor.2023.1216002

Wicks, L (2011). An Experimental Relative Skill Based Ranking System for Elite Level Judo. Abstracts of the 7th IAJR International Judo Research Symposium. Retrieved from: http://judoresearch.org/wp-content/uploads/2012/03/Lance-Wicks.pdf access on 15th April 2024.