Monitoring perceived stress, recovery and non-traumatic lower extremity injuries in competitive runners

Runners often sustain lower extremity injuries (19-79%) (van Gent et al, 2007). In a theoretical model it has been described that a disturbance in perceived stress and recovery can increase the risk of sustaining an injury (Williams & Andersen, 1998). Therefore, the purpose of this study was to investigate changes in perceived stress and recovery preceding an injury of competitive runners. Methods: Twenty-four competitive runners were monitored over one full training season (46 weeks). Every week, the runners filled an on-line RESTQ-sport (Nederhof et al, 2008). Furthermore, runners and their coaches kept a log with injuries and physical complaints. A non-traumatic injury was defined as any pain, soreness or injury that was not caused by trauma and resulted from training and led to a decrease in training duration or training intensity for at least one week (Jacobsson et al, 2013). Because baseline levels of perception of stress and recovery vary largely between runners, the 19 scales of the RESTQ-Sport were normalized to Z-scores based on the runner’s individual average and standard deviation of the whole season (excl. injured periods). The normalized scores of 1, 2 and 3 weeks before the first sustained injury were compared to 0, which is the average normalized score, by repeated measures ANOVA’s. Results: Twenty-two runners sustained a non-traumatic lower extremity injury. Eight of these runners filled out the RESTQ-Sport all 3 weeks preceding the injury and their data was used for further analysis. The injuries sustained were non-traumatic injuries of the knee, Achilles tendon, ankle, foot and shin. It was shown that 1 week preceding the injury, runners scored lower than the average normalized score on “Success” (Z-score: -0.68±0.62) and 2 weeks preceding the injury runners scored higher than their average on “Fitness/Injuries” (Z-score: 1.04±1.12). Discussion: A decrease in perceived success may be a marker to predict a non-traumatic lower extremity injury. Also an increase in the perception of muscle ache, soreness, pain and vulnerability to injury (“Fitness/Injury”) preceded injuries. Thereby, monitoring changes in individual stress and recovery may help to prevent non-traumatic injuries