Impact of coach education and practical experience on performance gains in young elite karate athletes following an 8-week plyometric and agility training program

This exploratory, quasi-experimental study examined how coach educational background influences training-induced adaptations in young elite karate athletes. Forty-five national-level under-15 karatekas were assigned to three non-randomized groups based on their coach profile: sports instructor (School 1), university-trained sports teacher (School 2), or a combined supervision team (School 3). Each coaching unit independently designed an eight-week plyometric and agility program under standardized constraints, allowing the program characteristics to reflect their methodological expertise. Pre- and post-intervention assessments included anthropometry, muscular power, linear sprint time, change-of-direction (COD) speed, and dynamic balance. Data were analyzed using ANCOVA with baseline scores as covariates. Effect sizes were expressed as partial eta squared ( η p 2 ) for between-group effects and Cohen's d for descriptive changes. ANCOVA revealed no significant group effects for BMI, body fat percentage, squat-jump, or 10-m sprint. Conversely, significant between-group differences favoring School 3 were observed in most key performance metrics ( p < 0.01). School 3 demonstrated superior outcomes for muscular power (countermovement jump, drop jump, standing long jump, medicine-ball tests; η p 2 up to 0.67), linear sprint time (15-m sprint; η p 2 = 0.30), modified COD T-test (MCOD-T; η p 2 =0.67), and Y-balance test - composite score (YBT-CS; η p 2 =0.40). Post-hoc tests confirmed School 3 outperformed School 1 and School 2 with large effect sizes across these variables (e.g., MCOD-T: d = 3.59 vs. School 1; 15-m sprint: d = 1.63 vs. School 1). We conclude that integrating academic knowledge with sport-specific practical experience provides a stronger foundation for designing structured, progressive, and effective training programs that maximize positive performance adaptations.