Effects of a Shortened Winter Break on Injury Incidence within the German Male Professional Soccer Leagues

PURPOSE: To investigate whether a difference in winter break duration affects injury incidence and severity in male professional soccer. METHODS: Due to marketing and other considerations the winter break in German professional soccer was shortened from 6.5 to 3.5 weeks in the 2009/10 season. 7 clubs of the two highest German professional soccer leagues were followed over two half seasons (second half of the season 2008/09 and 2009/10). In the first year 184 players took part, in the second 188. Baseline information, injury incidence, location, severity and exposure time for training and competition were recorded by the teams' medical staff according to the "FIFA consensus statement on injury definitions and data collection procedures in studies of soccer" (Fuller et al. 2006). Player characteristics were: age 25.2±4.2 y, height 184±7 cm, weight 79±7 kg. RESULTS: 300 time loss injuries (2008/09 n=151, 2009/10 n=149) occurred over the two half seasons, 53% (n=159) of them during games. The overall injury incidence per 1000 soccer hours was 5.90 [95% CI 4.96-6.84] in 2008/09 and 6.57 [95% CI 5.51-7.62] in 2009/10, the rate of match injuries being 9 times higher compared to training (match injuries/1000 hours: first season 31.5 [95% CI 25.0-38.0], second season 26.5 [95% CI 20.2-32.7]; training injuries/1000 hours: first season 2.68 [95% CI 2.01-3.36], second season 3.98 [95% CI 3.11-4.86]. Training incidence was significantly higher in the second season (incidence rate ratio (IRR) 1.49 [95% CI 1.07-2.08], p=0.02). Over the whole study period 83% of the injuries affected the lower limb esp. thigh (29%), knee (21%) and ankle (17%). The risk to sustain a knee injury was significantly higher in 2009/10 (IRR 1.84 [95% CI 1.05-2.88], p=0.03). There was a tendency towards a higher incidence of moderate and severe injuries resulting in time loss of more than 7 days in 2009/10 (IRR 1.36 [95% CI 0.97-1.90], p=0.07). CONCLUSION: Shortening the winter break from 6.5 to 3.5 weeks did not affect overall injury incidence but increased the incidence of training and knee injuries and probably also the injury severity amongst German male professional soccer players. The shortened preparation time might have raised intensity and competitiveness of training. The injury incidence in Germany lies within the range of European top soccer leagues.