The effect of concurrent high-intensity interval training and resistance training on the lower body maximal strength and explosive power: A updated systematic review and meta-analysis

BACKGROUND: Endurance training can have a negative impact on strength training and may lead to reduced strength gains, known as the interference effect. However, high-intensity interval training (HIIT) as an endurance training mode may reduce this interference effect. OBJECTIVE: This systematic review and meta-analysis aim to investigate the effects of concurrent HIIT and resistance training (RT) on lower body explosive strength and maximum strength. METHODS: Five electronic databases were searched. Subgroup analyses were performed to assess the effects of HIIT modality, training status, and training duration on strength development following concurrent HIIT and RT. RESULTS: Meta-analysis showed that compared to RT alone, concurrent HIIT and RT will not affect the development of countermovement jump (CMJ) (WMD = -0.17, 95%CI = -1.45 to -1.11) and half squat (WMD = -0.05, 95%CI = -2.42 to 2.32). Further, subgroup analysis revealed that HIIT-running workout was conducive to the development of both CMJ and half squat. Longer training duration was found to be more effective in developing CMJ, while shorter training duration was more suitable for developing half squat. Additionally, athletes showed greater improvement than non-athletes. CONCLUSIONS: Combining HIIT and RT can enhance CMJ and half squat. The results of intervention are moderated by training variables and training status.