Interventions
The control group only received GP-led usual care. The content of usual care was based on the Dutch Guideline for GPs and best practice.The intervention group received, in addition to GP-led usual care, an 8-week standardised neuromuscular training programme. The free application ‘Versterk je enkel’ (‘Strengthen your ankle’) guided participants through the programme. Participants were instructed to perform three training sessions per week. Every session consisted of six exercises, which became more difficult in time and were performed in different conditions (with eyes open or shut, with or without a handhold, on an even or uneven surface) (Supplementary Information S1 [in Dutch]).