Debunking the myths about training load, injury and performance: empirical evidence, hot topics and recommendations for practitioners

BACKGROUND Since 2000, there has been a rapid growth in training load and injury research. In the past 5 years alone, a total of 38 studies (from as many as 24 different research groups, and 11 different sports) have investigated the relationship between loading profiles and injury. Despite the growing body of literature examining training load and injury, there is often a disconnect between this evidence and the actual training programmes prescribed in practice. In this paper, some common myths and misconceptions about training load and its role in injury and performance are reviewed. MYTHS AND MISCONCEPTIONS Common myths relating to training load (the role of training load in injuries, the '10% rule', the influence of spikes and troughs on injury risk and the acute:chronic workload ratio (ACWR)) are explored and discussed. Although the likelihood of injury is increased at an ACWR of ≥1.5 (on average), the difference between robust and fragile athletes can largely be explained by three key categories of moderators of the workload-injury relationship; 'ideal' age (ie, not too young or too old), physical qualities (eg, well-developed aerobic fitness, speed, repeated-sprint ability and lower body strength) and high chronic training load all decrease the risk associated with a given spike in workload. Rather than focusing solely on the ACWR as has been done in some studies, practitioners are advised to stratify players according to these three moderators of the workload-injury relationship (eg, age, training and injury history, physical qualities), and interpret internal and external load variables in combination with well-being and physical readiness data. When prescribing training load, the practitioner also needs to factor in injury risk factors such as poor biomechanics, academic and emotional stress, anxiety, inadequate sleep and stress-related personality traits. SUMMARY Rapid increases in training and competition workloads and low chronic workloads are associated with greater injury risk. These findings suggest that appropriately staged training programmes may reduce injury risk in athletes. There is an urgent need for randomised controlled trials to test this working hypothesis.