The relationship between match frequency and in jury risk in soccer International SportMed Journal, Vol.14 No.3, September 2013, pp.139-147. Available at URL: http://www.ismj.com 139 Official Journal of FIMS (International Federation of Sports Medicine) ISMJ International SportMed Journal Original research article The influence of match frequency on the risk of injury in professional soccer *Mr Javier Vilamitjana, MSc; Dr Néstor Lentini, MD; Mr Emilio Masabeu, PT CENARD (Centro Nacional de Alto Rendimiento Deportivo, National Centre of High Performance Athletics), Exercise Physiology Laboratory, Crisólogo Larralde 1050, C1429BSN, Buenos Aires, Argentina *Corresponding author. Address at the end of text Abstract Background: To the best of these authors’ knowledge, no previous study of professional soccer players playing different match frequencies has been conducted to investigate the risk of injury at the highest club competitive level in South America. Research question: To analyse the risk of injury in professional soccer players involved in two tournaments with different match frequencies. Type of study: Prospective cohort study. Method: A total of 95 professional players from several Argentinian teams were included. Forty players were involved only in the National Championship (Low Match Frequency, LMF) and 55 players took part in both tournaments: the National Championship and the Libertadores Cup (High Match Frequency, HMF). Exposure to football and injury incidence, severity and distribution were compared between LMF and HMF players. Results: HMF players had greater exposure to matches (18.6 vs. 14 matches per season p<0.01), whereas exposure to training did not differ. There was a higher risk of injury during training (4.5 vs. 1.2 /1000 h, p<0.01) and total exposure (8.9 vs. 5.0 /1000 h, p<0.01) in HMF players than in LMF players, whereas no difference was observed with respect to matches played. After an injury, HMF players had longer absences from matches played (3.5 vs. 1 match, p<0.01), training (14.4 vs. 6.8 days, p<0.01) and total exposure (21.7 vs. 9.4 days, p<0.01). The most prevalent diagnoses were muscular and tendon injuries more frequently observed in HMF players (55.4 % vs. 44.8 %, p<0.05). Conclusions: Professional soccer players involved in two tournaments are exposed to a higher risk of injury. This phenomenon would have a greater influence on training sessions than on matches played. Keywords: soccer; match frequency; injury risk, injury severity Mr Javier Vilamitjana, MSc Mr Vilamitjana has a Master of Science’s degree in Health and Physical Education, and is a member of the Cenard Physiology Laboratory. His main responsibility involves the physical evaluation of professional soccer players. His main research areas are physiology and injury prevention. Email: vilamitjana@yahoo.com Dr Néstor Lentini, MD Dr Lentini is the director of the Cenard Medical Department, and doctor of the delegation representing Argentina at the Olympic and Pan-American Games. He is in charge of the Cenard Physiology Laboratory. His main research area is sports medicine. Email: nestorlentini@yahoo.com.ar