Inspiratory Muscle Training Effects on Cycling During Acute Hypoxic Exposure

Lomax, Mitch; Massey, Heather; House, James R.

doi:10.3357/amhp.4780.2017

Cited by 10 publications

(16 citation statements)

References 19 publications

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“…Similar findings of improved respiratory muscle efficiency following in RMT have been observed in hypoxia as well (40, 64). Salazar-Martinez (64) found that six weeks of pressure-threshold IMT improved ventilatory efficiency in both normobaric normoxia and normobaric hypoxia, measured by the slope of the ratio of V̇ E and V̇CO 2 (V̇ E /V̇CO 2 slope) from the beginning of exercise until the second ventilatory threshold.…”

Section: Discussionsupporting

confidence: 84%

“…Importantly, although time trial performance was improved in both normoxia and hypoxia following RMT, TT performance was only correlated with OUES, and not V̇ E /V̇CO 2 slope, suggesting that, in the context of the influence of IMT on performance in hypoxia, OUES may be a better index of ventilatory efficiency than V̇ E /V̇CO 2 slope. Lomax et al (40) confirmed that ventilatory efficiency, estimated by the ratio of peripheral capillary oxygen saturation (S p O 2 ), measured by pulse oximetry, to V̇ E (S p O 2 /V̇ E ) was improved following RMT in hypoxia, but observed no differences in S p O 2 /V̇ E in normoxia following RMT. The authors speculated that an increase in lung diffusion capacity could be a potential mechanism, similar to the findings of Downey et al (14), although this hypothesis needs to be further investigated.…”

Section: Discussionmentioning

confidence: 95%

“…Therefore, RMT has been investigated as a strategy to minimize the deleterious effects of hypoxia on exercise capacity. Lomax et al (40) found that four weeks of pressure-threshold IMT significantly increased inspiratory muscle strength and arterial oxygen saturation, reduced minute ventilation (V̇ E ) and carbon dioxide output (V̇CO 2 ) during fixed-intensity sub-maximal cycle ergometry tests. Interestingly, these observations occurred in the absence of inspiratory muscle fatigue, suggesting that inspiratory muscle fatigue is not required in order for RMT to be of benefit.…”

Section: Discussionmentioning

confidence: 99%

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Recent Advancements in Our Understanding of the Ergogenic Effect of Respiratory Muscle Training in Healthy Humans: A Systematic Review

Shei

2018

Journal of Strength and Conditioning Research

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Shei, R-J. Recent advancements in our understanding of the ergogenic effect of respiratory muscle training in healthy humans: a systematic review. J Strength Cond Res 32(9): 2674-2685, 2018-Respiratory muscle training (RMT) has been shown to be an effective ergogenic aid for sport performance. Respiratory muscle training has been documented to improve performance in a wide range of exercise modalities including running, cycling, swimming, and rowing. The physiological effects of RMT that may explain the improvements in performance have been proposed to include diaphragm hypertrophy, muscle fiber-type switching, improved neural control of the respiratory muscles, increased respiratory muscle economy, attenuation of the respiratory muscle metaboreflex, and decreases in perceived breathlessness and exertion. This review summarizes recent studies on the ergogenicity and mechanisms of RMT since 2013 when the topic was last systematically reviewed. Recent evidence confirms the ergogenic effects of RMT and explores different loading protocols, such as concurrent exercise and RMT (i.e., "functional" RMT). These studies suggest that adapting new training protocols may have an additive improvement effect, but evidence of the efficacy of such an approach is conflicting thus far. Other recent investigations have furthered our understanding of the mechanisms underpinning RMT-associated improvements in performance. Importantly, changes in ventilatory efficiency, oxygen delivery, cytokine release, motor recruitment patterns, and respiratory muscle fatigue resistance are highlighted as potential mechanistic factors linking RMT with performance improvements. It is suggested that future investigations focus on development of sport-specific RMT loading protocols, and that further work be undertaken to better understand the mechanistic basis of RMT-induced performance improvements.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

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Recent Advancements in Our Understanding of the Ergogenic Effect of Respiratory Muscle Training in Healthy Humans: A Systematic Review

Shei

2018

Journal of Strength and Conditioning Research

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“…All of the cross-sectional studies discussed here (see Supplementary Table 1) demonstrated that RMT could bean useful tool for improving ventilatory efficiency and delaying the onset of premature fatigue during exercise in conditions of hypoxia (Downey et al, 2007; Esposito et al, 2010; Lomax, 2010; Helfer et al, 2016; Lomax et al, 2017; Salazar-Martínez et al, 2017). Only Esposito et al (2010) were somewhat cautious with the benefits of RMT for physical performance in hypoxia.…”

Section: Resultsmentioning

confidence: 90%

“…Under these conditions, subjects are commonly advised to follow various recommendations: (1) to rest adequately, (2) to optimize nutrition and hydration, (3) iron intake and, (4) to perform only moderate physical activity. Recently, the inclusion of RMT has been proposed as a preparatory method to enhance the respiratory muscle efficiency 4–6 weeks before athletes and climbers are exposed to hypoxia/altitude (Downey et al, 2007; Esposito et al, 2010; Lomax, 2010; Helfer et al, 2016; Lomax et al, 2017; Salazar-Martínez et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Putative Role of Respiratory Muscle Training to Improve Endurance Performance in Hypoxia: A Review

et al. 2019

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Respiratory/inspiratory muscle training (RMT/IMT) has been proposed to improve the endurance performance of athletes in normoxia. In recent years, due to the increased use of hypoxic training method among athletes, the RMT applicability has also been tested as a method to minimize adverse effects since hyperventilation may cause respiratory muscle fatigue during prolonged exercise in hypoxia. We performed a review in order to determine factors potentially affecting the change in endurance performance in hypoxia after RMT in healthy subjects. A comprehensive search was done in the electronic databases MEDLINE and Google Scholar including keywords: “RMT/IMT,” and/or “endurance performance,” and/or “altitude” and/or “hypoxia.” Seven appropriate studies were found until April 2018. Analysis of the studies showed that two RMT methods were used in the protocols: respiratory muscle endurance (RME) (isocapnic hyperpnea: commonly 10–30′, 3–5 d/week) in three of the seven studies, and respiratory muscle strength (RMS) (Powerbreathe device: commonly 2 × 30 reps at 50% MIP (maximal inspiratory pressure), 5–7 d/week) in the remaining four studies. The duration of the protocols ranged from 4 to 8 weeks, and it was found in synthesis that during exercise in hypoxia, RMT promoted (1) reduced respiratory muscle fatigue, (2) delayed respiratory muscle metaboreflex activation, (3) better maintenance of SaO2 and blood flow to locomotor muscles. In general, no increases of maximal oxygen uptake (VO2max) were described. Ventilatory function improvements (maximal inspiratory pressure) achieved by using RMT fostered the capacity to adapt to hypoxia and minimized the impact of respiratory stress during the acclimatization stage in comparison with placebo/sham. In conclusion, RMT was found to elicit general positive effects mainly on respiratory efficiency and breathing patterns, lower dyspneic perceptions and improved physical performance in conditions of hypoxia. Thus, this method is recommended to be used as a pre-exposure tool for strengthening respiratory muscles and minimizing the adverse effects caused by hypoxia related hyperventilation. Future studies will assess these effects in elite athletes.

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Inspiratory muscle training at sea level improves the strength of inspiratory muscles during load carriage in cold-hypoxia

et al. 2020

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Inspiratory muscle training (IMT) and functional IMT (IMT F : exercise-specific IMT activities) has been unsuccessful in reducing respiratory muscle fatigue following load carriage. IMT F did not include load carriage specific exercises. Fifteen participants split into two groups (training and control) walked 6 km loaded (18.2 kg) at speeds representing ~50%VȮ 2max in coldhypoxia. The walk was completed at baseline; post 4 weeks IMT and 4 weeks IMT F (five exercises engaging core muscles, three involved load). The training group completed IMT and IMT F at a higher maximal inspiratory pressure (P imax ) than controls. Improvements in P imax were greater in the training group post-IMT (20.4%, p = 0.025) and post-IMT F (29.1%, p = 0.050) compared to controls. Respiratory muscle fatigue was unchanged (p = 0.643). No other physiological or subjective measures were improved by IMT or IMT F . Both IMT and IMT F increased the strength of respiratory muscles pre-and-post a 6 km loaded walk in cold-hypoxia.

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Inspiratory Muscle Training Effects on Cycling During Acute Hypoxic Exposure

Cited by 10 publications

References 19 publications

Recent Advancements in Our Understanding of the Ergogenic Effect of Respiratory Muscle Training in Healthy Humans: A Systematic Review

Recent Advancements in Our Understanding of the Ergogenic Effect of Respiratory Muscle Training in Healthy Humans: A Systematic Review

Putative Role of Respiratory Muscle Training to Improve Endurance Performance in Hypoxia: A Review

Inspiratory muscle training at sea level improves the strength of inspiratory muscles during load carriage in cold-hypoxia

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