Combining Normobaric Hypoxia With Short-term Resistance Training Has No Additive Beneficial Effect on Muscular Performance and Body Composition

Abstract

The aim of this study was to determine the effects of short-term resistance training combined with systemic hypoxia on muscular performance and body composition. Eighteen resistance-untrained men (21.3 ± 2.0 years, 172.7 ± 5.5 cm, 67.3 ± 9.7 kg) were matched and assigned to 2 experimental groups: performing 6 weeks of squat exercise training under normobaric hypoxia (H, FiO2 = 15%) or normoxia (N). In both groups, subjects performed 3 weekly sessions (a total of 18 sessions) of 3 sets of back squat at 10-repetition maximum with 2 minutes of rest between sets. Dynamic, isometric, and isokinetic leg strength and body composition were measured under normoxia before and after resistance training. Squat 1 repetition maximum (1RM) improved significantly (p ≤ 0.05) after resistance training in both H and N groups (88.9 ± 16.9 to 109.4 ± 17.0 kg and 90.0 ± 12.2 to 105.6 ± 13.3 kg, respectively). However, there were no changes in maximal isometric and isokinetic leg strength, lean body mass, and fat mass after the resistance training in both groups. In addition, no significant differences were observed between H and N groups in squat 1RM, maximal isometric and isokinetic leg strength, and body composition. The major findings of this study suggest that short-term resistance training performed under normobaric hypoxia has no additive beneficial effect on muscular performance and body composition. In practical terms, our data suggest that the use of systemic hypoxia during short-term resistance training is not a viable method to further enhance muscular performance and body composition in previously resistance-untrained men.

Intermittent hypoxic resistance training: Is metabolic stress the key moderator?

“…These studies are summarized in [11,17]. However, other investigations using similar training loads but with extended inter-set recovery intervals (90-120 s) have demonstrated no added benefit for training under hypoxia [12,13]. Although it is too early to make definitive recommendations based on only these investigations, we hypothesize that low-and moderate-load IHRT might only provide added benefit when relatively brief inter-set rest periods are used.…”

“…However, if the inter-set recovery interval is extended past these durations, the hypoxia-mediated alterations in 12 energy system contributions and subsequent metabolic stress are likely to be attenuated. This is highlighted by recent research from Ho, et al [12] and Kon, et al…”

“…Research has demonstrated that hypertrophic and strength responses can be enhanced by breathing hypoxic air during low-load (20% 1RM) [6,10] and moderate-load (70% 1RM) [11] resistance training. However, some more recent evidence has provided conflicting results, reporting no additional benefit for muscular development following resistance training in systemic hypoxia [12,13].…”

Physical Performance During High-Intensity Resistance Exercise in Normoxic and Hypoxic Conditions

“…It is therefore likely that the three-minute inter-set recovery employed in the current study was sufficient to allow nearcomplete PCr resynthesis. To this point, a recent investigation using moderate-intensity IHRT (10RM) with longer inter-set rest periods than typically used at that intensity (120 s) has demonstrated no added hypertrophic or strength benefit for IHRT (15). These results contrast those of Nishimura et al (25), and could indicate that longer inter-set rest intervals attenuate any hypoxia-mediated increases in metabolic stress, and subsequent downstream anabolic responses.…”

Resistance Training Using Different Hypoxic Training Strategies: a Basis for Hypertrophy and Muscle Power Development

“…No differences between conditions in the theoretical maximal strength were reported by Kurobe’s team, but 1RM estimates in high repetition tests to failure (10RM, ~75% 1RM) may be unreliable due to fatigue and mechanical stress [53, 54]. Contrary to these findings, Ho et al [15] concluded that 6 weeks of short-term resistance training (3 sets of 10RM; 2 min rest) under NH (15% FiO 2 ) offered no additional benefit to muscular performance or body composition. Likewise, Kon et al [16] observed no strength or muscle size gains in response to bench press and leg press (16 sessions of 5 sets × 10 repetitions at 70% 1RM; 90 s of rest) though they did detect enhanced skeletal muscle endurance and angiogenesis.…”