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Endurance training of respiratory muscles improves cycling performance in fit young cyclists
Open accessAbstract
Background Whether or not isolated endurance training of the respiratory muscles improves whole-body endurance exercise performance is controversial, with some studies reporting enhancements of 50% or more, and others reporting no change. Twenty fit (VO2 max 56.0 ml/kg/min), experienced cyclists were randomly assigned to three groups. The experimental group (n = 10) trained their respiratory muscles via 20, 45 min sessions of hyperpnea. The placebo group (n = 4) underwent "sham" training (20, 5 min sessions), and the control group (n = 6) did no training. Results After training, the experimental group increased their respiratory muscle endurance capacity by 12%. Performance on a bicycle time trial test designed to last about 40 min improved by 4.7% (9 of 10 subjects showed improvement). There were no test-re-test improvements in either respiratory muscle or bicycle exercise endurance performance in the placebo group, nor in the control group. After training, the experimental group had significantly higher ventilatory output and VO2, and lower PCO2, during constant work-rate exercise; the placebo and control groups did not show these changes. The perceived respiratory effort was unchanged in spite of the higher ventilation rate after training. Conclusions The results suggest that respiratory muscle endurance training improves cycling performance in fit, experienced cyclists. The relative hyperventilation with no change in respiratory effort sensations suggest that respiratory muscle training allows subjects to tolerate the higher exercise ventilatory response without more dyspnea. Whether or not this can explain the enhanced performance is unknown.
Overview
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TL;DR
In fit experienced cyclists, 20 sessions of respiratory muscle endurance training increased respiratory muscle endurance by 12% and improved ~40-min cycling time-trial performance by 4.7%, with higher exercise ventilation and VO2 but unchanged dyspnea. The mechanism linking these changes remains unknown.
Key findings
- The RMET group (n = 10) increased sustainable ventilatory capacity by 12%, while respiratory muscle strength (maximal inspiratory and expiratory mouth pressures) did not change significantly.
- Time-trial performance improved in 9 of 10 RMET subjects; average performance time fell from 47.1 ± 5.5 min to 44.9 ± 5.5 min, a 4.75% reduction (P < 0.05). The percent change was -4.75 ± 1.6% in RMET versus 0.46 ± 1.8% in control/placebo (P = 0.015).
- After RMET, VE and VO2 during constant work-rate exercise were significantly higher, while heart rate and perceived breathing/leg effort were unchanged. The change in VE correlated with improved time-trial performance (r = -0.522, P = 0.0183).
- Control and placebo groups showed no significant changes in respiratory muscle endurance or cycling performance.
Methods
- Twenty fit, experienced cyclists/triathletes (VO2 max 56.0 ml/kg/min) were assigned to RMET (n = 10), placebo sham training (n = 4), or no-training control (n = 6); the intervention lasted 4 weeks with 20 sessions. Pre- and post-training tests included sustainable ventilatory capacity, maximal mouth pressures, VO2 max, constant work-rate cycling endurance, and a fixed-work time-trial performance test.
- RMET used hyperpnea with target ventilation; placebo used 5-min low-intensity sessions; controls did no respiratory muscle training. Control and placebo groups were combined after no significant differences were found between them.
- Analyses used two-way repeated-measures ANOVA, Kruskal-Wallis one-way ANOVA on ranks for non-normal time-trial data, and Spearman rank correlation for the VE-performance relation; test reproducibility was assessed by coefficient of variation.
Limitations
- Stated: the mechanism behind either the enhanced performance or the enhanced ventilatory response after RMET remains unknown; the study avoided invasive measures that could have provided mechanistic insight.
- Stated: small sample size, particularly the placebo (n = 4) and control (n = 6) groups, led to combining those groups for statistical comparisons.
- Evident in the text: the abstract reports 45-min training sessions and lower PCO2, whereas the Methods state experimental sessions lasted 30 min and the Results state PETCO2 was not significantly different after training; these inconsistencies are not reconciled. The VE-performance relationship is correlational and cannot establish causation.
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In the paper
“Two-tailed t-tests revealed that differences in sustainable ventilatory capacity, exercise performance and exercise VE between the control group and the placebo training group on both the time trial and constant work-rate exercise tests (see below) were not significantly different.”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Methods > Statistical analysis
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“There were no consistent changes observed in the control/placebo group (Table 3).”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Results > Cardiorespiratory responses during the time trial tests, before and after RMET
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In the paper
“Performance time did not change significantly in the control/placebo group (Table 2 and Figure 3, bottom panel).”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Results > Exercise performance following RMET
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In the paper
“The correlation coefficient was -0.522, and was statistically significant (P = 0.0183).”
- Also stated in: § Correlation between increased VE and improved exercise performance after RMET · plain
“we found a significant, inverse correlation between the change in VE and the change in performance time in all 20 subjects, with the subjects that ventilated more after the training period having better performance.”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Results > Correlation between the change in time trial performance and the change in VE
plainstates an associationn = 20 ·- Asserted: passes — The authors put it forward as true.
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- Also stated in: § Correlation between increased VE and improved exercise performance after RMET · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In all RMET subjects, VE and VO2 were higher in the post-RMET time trial test compared to the pre-RMET time trial test (Table 3).”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Results > Cardiorespiratory responses during the time trial tests, before and after RMET
plainn = 4- Asserted: passes — The authors put it forward as true.
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In the citing paper
“However, in studies using CLTs at intensities below the threshold and including a sham-training group, improvements in the RMT groups exceeded those of the sham-training groups [66,71,79,85,88] with only one exception.[83]”
From Effect of Respiratory Muscle Training on Exercise Performance in Healthy Individuals: A Systematic Review and Meta-Analysis (2012) · cites this paper as [83]
In the citing paper
“Of the fifteen studies testing with a CLT below the 85% threshold, only three specified changes in respiratory sensations, two [79,88] of them reported a significant decrease while one [83] did not.”
From Effect of Respiratory Muscle Training on Exercise Performance in Healthy Individuals: A Systematic Review and Meta-Analysis (2012) · cites this paper as [83]
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Rated major: it would touch a result — a value a result rests on, reported and recomputed p-values on opposite sides of the significance level, two passages that conflict with no sign which is right, or a cited work retracted before this paper was published.
In the paper
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Abstract > Background
“The experimental group (n = 10) trained their respiratory muscles via 20, 45 min sessions of hyperpnea.”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Methods > Respiratory muscle endurance training
“For the experimental subjects, each training session lasted 30 minutes.”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Results > Exercise performance following RMET
“the performance of all subjects before and after the intervention period is shown in Fig. 3.”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Methods > Sustainable Ventilatory Capacity (SVC)
“Further analysis of each test consisted of finding the average ventilation over 30 breaths occurring at the beginning of each minute of the first six-minutes of the test (Fig. 3).”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Results > Reproducibility of the exercise tests
“The coefficient of variation for the time trial test was 3.94 % (Fig. 1, top panel)”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Discussion > Exercise performance after training of the respiratory muscles
“the fixed end-point performance test, or "time trial" that we used has a coefficient of variation of 3.89 %”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Abstract > Background
“Twenty fit (VO2 max 56.0 ml/kg/min), experienced cyclists were randomly assigned to three groups.”
§ Endurance training of respiratory muscles improves cycling performance in fit young cyclists > Methods > Subjects
“Using a standard randomization procedure, we initially assigned 10 subjects (3 female, 7 male) to the RMET group and 6 to a control group (1 female, 5 male). We subsequently added 4 additional subjects (4 males) that did "placebo training" (see below).”
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Metadata
- Authors
- Holm, P., Sattler, A., & Fregosi, R. F.
- Affiliations
- University of Arizona (US)
- Corresponding author
- Fregosi, Ralph F
- ORCID
- Fregosi, Ralph F
- Venue
- BMC Physiology
- Published
- 2004-05-06
- Volume
- 4
- Issue
- 1
- Pages
- 9-9
- ISSN
- 1472-6793 (ISSN-L)
- PMC
- PMC419707
- OpenAlex
- W2150965621
- Semantic Scholar
- c0d26665b5f24f1ed97354dd6e85442edce363e2
- Cited by
- 96
- References
- 28
- Citations by year
- 2026: 3 · 2025: 5 · 2024: 4 · 2023: 2 · 2022: 4 · 2021: 2 · 2020: 2 · 2019: 6 · 2018: 3 · 2017: 5 · 2016: 4 · 2015: 2 · 2014: 3 · 2013: 6 · 2012: 9
- FWCI
- 2.80
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- BMC Physiology (publishedVersion)
- PubMed (publishedVersion)
- PubMed Central (publishedVersion, other-oa)
- Funders
- University of Arizona
- National Heart, Lung, and Blood Institute (R01HL051056)
- Topics
- Health Sciences › Medicine › Physiology (medical) › Cardiovascular and exercise physiology
- Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
- Social Sciences › Psychology › Developmental and Educational Psychology › Sport Psychology and Performance
- Keywords
- respiratory muscle training, endurance training, cycling performance, hyperpnea, respiratory muscle endurance, ventilatory response, exercise tolerance, cyclists, hyperventilation
- MeSH terms
- Adolescent, Adult, Bicycling, Breathing Exercises, Carbon Dioxide, Dyspnea, Exercise Test, Female, Humans, Male, Middle Aged, Oxygen Consumption, Partial Pressure, Physical Endurance, Physical Fitness, Pulmonary Ventilation, Respiratory Muscles, Reproducibility of Results, Treatment Outcome, Exercise Tolerance
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