Evaluating the impact of a coach development intervention for improving coaching practices and player outcomes in netball: The MASTER coaching randomized control trial

The aim of this randomized controlled trial was to evaluate the impact of a novel 8-week coach development intervention (MASTER) on game-based coaching practices of netball coaches from one netball club (n = 16; 8 intervention, 8 active-control; NSW Australia), and player outcomes for the junior athletes being coached. The multi-component MASTER intervention aimed to educate coaches on how to design and implement high quality game-based coaching sessions. The core pillar of MASTER is 'positive coaching,' delivered through games-based coaching practices. At baseline and 10-weeks, two coaching sessions per coach were filmed and assessed using the MASTER assessment tool. Players (8-16yrs; n = 85) were videoed during structured gameplay, with three aspects of game play assessed using Game Performance Assessment Instrument. Coaches and players (n = 75; 12-16yrs) completed a perceptions questionnaire. Using linear mixed model ITT analysis, significant interventions effects were observed for the primary outcome: percentage of time spent performing playing-form activities [25.7% (95% CI (7.79-43.65), P = 0.008, d = 1.52]. Significant interventions effects were also observed for coach perceptions, player game skills, and player self-perceptions (P < 0.05). No significant changes were observed for player enjoyment, motivation, or wellbeing. The MASTER program was effective in improving coach and player self-perceptions, and coaching practices of netball coaches during training sessions.