Frontiers in Sports and Active Living (Jan 2025)
Different whole body HIIT protocols do not promote different muscle thickness and functional adaptations among healthy physically active subjects
Abstract
IntroductionDespite robust evidence on the benefits of high intensity interval training using body weight (WB-HIIT), the effects of different training configurations on morpho-functional adaptations are still unclear. Therefore, the aim of the present study was to assess the effects of two distinct WB-HIIT protocols on morphological and general fitness adaptations in healthy active young individuals.MethodsThirty-four participants (22 males and 12 females) were randomly assigned to one of the following groups: 30 s of all-out effort interspersed with 10 s of passive recovery (G30 × 10, n = 17) or 40 s of an all-out effort interspersed with 20 s of passive recovery (G40 × 20, n = 17). Nine exercises were performed for both protocols, in two weekly sessions, during a 6-week intervention period. Morphological (ultrasound-derived muscle thickness of the vastus lateralis [MTVL]) and general fitness (muscle endurance and maximal oxygen consumption) assessments were performed at pre- and post-intervention moments.ResultsBoth training protocols elicited significant improvements in all dependent variables (p < 0.05), with no significant between-group differences.ConclusionRegardless of the training configuration, both WB-HIIT programs serve as time-efficient strategies to induce changes in muscle thickness of the vastus lateralis and functional adaptations in healthy, physically active young individuals.
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