Table 1

Steps of the KTS followed in order to develop the TrailS6 intervention

Steps of KTSDescription of performed activities
Step 1: problem statementA prospective cohort study11 was conducted with the same source population of the current trial in order to investigate the burden of RRIs in Dutch trail runners.
Step 2: evidence descriptionA summary of the available scientific evidence on RRIs, mainly with published systematic reviews,17 46–48 was conducted, and this evidence was compiled with the results of the cohort study that was part of step 1 that investigated the burden of RRIs in Dutch trail runners.11
Step 3: KTGA KTG was composed of five participants:

  • One researcher in the field of sports injury prevention, who was also the chair of the KTG

  • Two trail runners

  • One healthcare professional, who is also a researcher in the field of RRIs

  • One stakeholder (head of MudSweatTrails)

Step 4: product developmentThe KTG had one face-to-face meeting in order to discuss the cumulative evidence-based information generated in steps 1 and 2 and to propose an intervention aimed at preventing RRIs in trail runners. Further discussions with the participants of the KTG were carried out in order to revise the intervention materials and to adapt them to the needs, preferences and reality of trail runners (ie, evidence–practice-based intervention). This process resulted in an online tailored advice intervention (TrailS6 ).
Step 5: evaluationThe evaluation of the intervention (TrailS6 ) was conducted with the current randomised controlled trial.