Heart Rate–Based Training Intensity and Its Impact on Injury Incidence Among Elite-Level Professional Soccer Players

Elite level professional soccer players are suggested to have increased physical, technical, tactical and psychological capabilities when compared to their sub-elite counterparts. Ensuring these players remain at the elite level generally involves training many different body systems to a high intensity or level within a short period of time. This study aimed to examine whether an increase in training volume at high intensity levels were related to injury incidence, or increased the odds of injury. Training intensity was assessed through time spent in two high- and very high- intensity zones of 85-<90% and ≥90% of maximal heart rate (T-HI and T-VHI, respectively), and all injuries were recorded over two consecutive seasons. Twenty-three elite professional male soccer players (meanSD age 25.64.6 years, stature 181.86.8 cm, and body mass of 79.38.1 kg) were studied throughout the 2-yrs span of the investigation. The results showed a mean of total injury incidence of 18.8 (95% CI 14.7 to 22.9) injuries per 1000 h of exposure. Significant correlations were found between training volume at high intensities and injury incidence (r=0.57, p=0.005). It was also revealed that players achieving more time in the T-VHI zone during training increased the odds of sustaining a match injury (odds ratio=1.87, 95% CI 1.12 to 3.12, p=0.02), but did not increase the odds of sustaining a training injury. Ensuring that training loads are not significantly exceeded causing accumulative fatigue within competitive matches may assist in reducing the number of injuries at the elite level of professional soccer.
Key Words: Football; athletic injuries; heart rate; odds ratio; risk.