Enhancing the Initial Acceleration Performance of Elite Rugby Backs. Part II: Insights From Multiple Longitudinal Individual-Specific Case-Study Interventions

Purpose: This study implemented 18-week individual-specific sprint acceleration training interventions in elite male rugby backs based on their pre-determined individual technical needs, and evaluated the effectiveness of these interventions. Methods: Individual-specific interventions were prescribed to five elite rugby backs over an 18-week period. Interventions were informed by the relationships between individual technique strategies and initial acceleration performance, and their strength-based capabilities. Individual-specific changes in technique and initial acceleration performance were measured at multiple time points across the intervention period, and compared to three control participants who underwent their normal sprint training. Results: Of the technique variables intentionally targeted during the intervention period, moderate to very large (ǀdǀ = 0.93 to 3.99) meaningful changes were observed in the participants who received an individual-specific intervention, but not in three control participants. Resultant changes to the intervention participants’ whole-body kinematic strategies were broadly consistent with the intended changes. Moderate to very large (ǀdǀ = 1.11 to 2.82) improvements in initial acceleration performance were observed in participants receiving individual-specific technical interventions, but not in the control participants or the participant who received an individual-specific strength intervention. Conclusions: Individual-specific technical interventions were more effective in manipulating aspects of acceleration technique and performance, compared with the traditional ‘one-size-fits-all’ approach adopted by the control participants. This study provides a novel, evidence-based approach for applied practitioners working to individualize sprint-based practices to enhance acceleration performance.