The design of the run Clever randomized trial: running volume, -intensity and running-related injuries

Background: Injury incidence and prevalence in running populations have been investigated and documented in several studies. However, knowledge about injury etiology and prevention is needed. Training errors in running are modifiable risk factors and people engaged in recreational running need evidence-based running schedules to minimize the risk of injury. The existing literature on running volume and running intensity and the development of injuries show conflicting results. This may be related to previously applied study designs, methods used to quantify the performed running and the statistical analysis of the collected data. The aim of the Run Clever trial is to investigate if a focus on running intensity compared with a focus on running volume in a running schedule influences the overall injury risk differently. Methods/design: The Run Clever trial is a randomized trial with a 24-week follow-up. Healthy recreational runners between 18 and 65 years and with an average of 1-3 running sessions per week the past 6 months are included. Participants are randomized into two intervention groups: Running schedule-I and Schedule-V. Schedule-I emphasizes a progression in running intensity by increasing the weekly volume of running at a hard pace, while Schedule-V emphasizes a progression in running volume, by increasing the weekly overall volume. Data on the running performed is collected by GPS. Participants who sustain running-related injuries are diagnosed by a diagnostic team of physiotherapists using standardized diagnostic criteria. The members of the diagnostic team are blinded. The study design, procedures and informed consent were approved by the Ethics Committee Northern Denmark Region (N-20140069). Discussion: The Run Clever trial will provide insight into possible differences in injury risk between running schedules emphasizing either running intensity or running volume. The risk of sustaining volume-and intensity-related injuries will be compared in the two intervention groups using a competing risks approach. The trial will hopefully result in a better understanding of the relationship between the running performed and possible differences in running-related injury risk and the injuries developed.