Skip to main content

ORIGINAL RESEARCH article

Front. Physiol.
Sec. Exercise Physiology
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1511961
This article is part of the Research Topic Responses and Adaptations to Novel Exercise Modalities View all 4 articles

The physiological responses to volume-matched high-intensity functional training protocols with varied time domains

Provisionally accepted
Jessica S Smith Jessica S Smith 1,2*Gabriella F Bellissimo Gabriella F Bellissimo 2,3Fabiano T Amorim Fabiano T Amorim 2
  • 1 SUNY Oneonta, Oneonta, United States
  • 2 University of New Mexico, Albuquerque, New Mexico, United States
  • 3 College of Idaho, Caldwell, Idaho, United States

The final, formatted version of the article will be published soon.

    Background: High-intensity functional training (HIFT) is typically performed with minimal or no rest periods including "rounds for time" (RFT) or "as many rounds or repetitions as possible" (AMRAP) design. Alternatively, some HIFT workouts can be performed with prescribed rest intervals (e.g., "every minute on the minute" [EMOM]) which may have significant effects on physiological responses. Purpose: To compare the physiological responses between two different HIFT workouts (EMOM and RFT) that were matched for total work volume (TWV). Methods:Twelve trained individuals (6 males and 6 females) performed two HIFT protocols, EMOM and RFT. Both the EMOM and RFT included 5 rounds of 5 power cleans, 8 kipping pull-ups, 6 dumbbell thrusters, and 10 burpees performed in this order. Measurements of heart rate (HR), expired gases (VO2), rating of perceived exertion (RPE) (1-10 scale), blood lactate (BLA), creatine kinase (CK), excess post-exercise oxygen consumption (EPOC), and muscle oxygen saturation (SmO2) were performed. Results: Time domains were significantly different for the EMOM and RFT workouts (20 vs. 12 ± 3 min, p < 0.00). There were significant differences between the EMOM and RFT for HR (153 ± 19 vs. 171 ± 12 bpm, p < 0.01), VO2 (30.8 ± 3 vs. 38.1 ± 5 ml/kg/min, p < 0.00), RPE (4 ± 1 vs. 7 ± 1, p < 0.00), and EPOC-AUC (3.5 ± 1.2 vs. 5.0 ± 1.3 ml/kg/min, p < 0.00); however, there were no significant differences in mean SmO2 (p = 0.44). An interaction effect revealed BLA was lower for the EMOM (6.5 ± 2.7 mmol/L) compared to RFT (11.2 ± 2.1 mmol/L) post-exercise (p < 0.00). Conversely, there was no interaction effect for CK (p < 0.16), yet a significant increase from pre-to post-exercise for both the EMOM and the RFT (p < 0.01). Conclusions: The RFT induced greater physiological stress compared to the EMOM indicating that prescribed rest intervals significantly affect the metabolic, cardiovascular, and perceptual responses during high-intensity functional exercise. Furthermore, the RFT may provide a greater cardiorespiratory stimulus while the EMOM may be more suitable for technique development and recovery in trained individuals.

    Keywords: cardiorespiratory fitness, muscular fitness, Resistance Training, High-intensity interval training, cross-training

    Received: 15 Oct 2024; Accepted: 12 Dec 2024.

    Copyright: © 2024 Smith, Bellissimo and Amorim. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Jessica S Smith, SUNY Oneonta, Oneonta, United States

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.