Affiliations: [a] Laboratory of the Metabolic Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), Centre de Recherche en Nutrition Humaine (CRNH) Auvergne, Clermont Auvergne University, Clermont-Ferrand, France | [b] Biostatistics Unit, DRCI, CHU Clermont-Ferrand, Clermont-Ferrand, France | [c] Observatoire National de l’Activité Physique et de la Sédentarité (ONAPS), Faculty of Medicine, Clermont Auvergne University, Clermont-Ferrand, France | [d] International Research Chair Health in Motion, Clermont Auvergne University Foundation, Clermont-Ferrand, France
Correspondence:
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Corresponding author: Léna Pélissier, Clermont Auvergne University, UPR 3533, Laboratory of the Metabolic Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), CRNH Auvergne, 3 rue de la Chebarde, 63 170 Aubière, France. E-mail: [email protected].
Abstract: BACKGROUND: Exploring the independent effect of mechanical discharge in response to weight loss (WL) seems necessary but remains highly challenging from a methodological point. Anti-gravity treadmills could be relevant to simulate a mechanical WL by body weight support (BWS), but their reliability remains unclear to properly explore exercise energy metabolism, especially at low degrees of alleviations. OBJECTIVE: The study aimed to evaluate the accuracy and reproducibility of an anti-gravity treadmill to generate BWS, and the reproducibility of cardiometabolic responses to an exercise performed at low degrees of BWS on this device. METHODS: Observed BWS of 18 normal-weight males was obtained twice at seven degrees of target BWS (i.e., 0, 3, 6, 9, 12, 15, 18%) using a digital scale inside the anti-gravity treadmill, and was compared to the expected BWS. Then, 15 of them performed 5-min bout of low-intensity walking exercise at these degrees of BWS in a randomized order, separated by 4-min rest. The exercise was identically repeated on three occasions separated by a minimum of 3 days. Energy metabolism and heart rate (HR) were measured throughout the exercise by indirect calorimetry and a HR monitor, respectively. RESULTS: The observed BWS were significantly different from the expected BWS (p< 0.001), and there was a high inter- and intra-individual variability in BWS generated by the anti-gravity treadmill. Results showed an overall good reliability of VO2 (intraclass correlation coefficients (ICC) values ranging from 0.67 to 0.85) and HR (ICC > 0.8) in response to exercise. An effect of the degree of BWS was observed for VO2 (p< 0.001), illustrating reduced values at 15% and 18% of BWS compared to 0, 3, and 6%. CONCLUSIONS: Such device might not be adapted to simulate low degrees of WL in normal-weight males, particularly when it comes to the exploration of energy metabolism.
Keywords: Lower-body positive pressure, accuracy, alleviation, exercise, energy metabolism
