Table 2

Overview of data collection of the outcome measures

TimelineWeek 0Weeks 1–10Week 11Week 11–52Week 53
Baseline data collectionPerformance test
(pretest)		InterventionWeekly questionnairePerformance test (post-test I)InterventionMonth 6Month 9Month 12Performance test (post-test II)
Subject’s activityFill out the questionnaire.Sprint and jump testsPerforming group-oriented instruction (NHE based on the schedule for the Nordics group)Fill out the questionnaireSprint and jump testsperforming group-oriented instruction
(Nordics group: Continue with the NHE programme once a week)		Fill out the questionnaireFill out the questionnaireFill out the questionnaireSprint and jump tests
LocationOnlineFootball fieldIn the subject’s own placeOnlineFootball fieldIn the subject’s own placeOnlineOnlineOnlineFootball field
Estimated time/duration5 min30 min5 min per session for Nordics group (maximum three times per week)5 min per questionnaire30 min5 min per session (Nordics group)5 min5 min5 min30 min

  • Performance study in the Netherlands and Indonesia (n=36).

  • NHE, Nordic hamstring exercise.