AUTHOR=Yogev Assaf , Arnold Jem I. , Nelson Hannah , Rosenblat Michael A. , Clarke David C. , Guenette Jordan A. , Sporer Ben C. , Koehle Michael S. 

TITLE=The effects of endurance training on muscle oxygen desaturation during incremental exercise tests: a systematic review and meta-analysis

JOURNAL=Frontiers in Sports and Active Living

VOLUME=6

YEAR=2024

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2024.1406987

DOI=10.3389/fspor.2024.1406987

ISSN=2624-9367

ABSTRACT=<sec><title>Objective</title><p>Minimum muscle oxygen saturation (SmO<sub>2</sub>min) measured via near-infrared spectroscopy (NIRS) is a common measure during incremental exercise testing (IET). Our objective was to determine the effects of pre-to-post endurance training on SmO<sub>2</sub>min (ΔSmO<sub>2</sub>min) during an IET, using a meta-analysis.</p></sec><sec><title>Data sources</title><p>MEDLINE, EMBASE, and SPORTDiscus.</p></sec><sec><title>Study selection</title><p>Studies including healthy individuals had to meet the following criteria: (1) endurance training intervention; (2) peripheral muscle NIRS; (3) incremental exercise test pre/post training; (4) SmO<sub>2</sub> or analogous saturation parameter measured.</p></sec><sec><title>Analysis</title><p>A PEDro scale was used for risk of bias analysis. A random effect meta-analysis model was used to synthesize the effect of training on ΔSmO<sub>2</sub>min in individual studies. Statistical heterogeneity was quantified using <italic>I<sup>2</sup></italic> statistic. A meta-regression was used to estimate the effect of training on the relationship between peak cycling power output (Wpeak), peak pulmonary oxygen uptake (V˙O<sub>2</sub>peak), and ΔSmO<sub>2</sub>min. A mixed-effect model was used to estimate categorical variables.</p></sec><sec><title>Results</title><p>Five studies met the inclusion criteria. No difference in SmO<sub>2</sub>min was detected following training pre- and post-intervention IETs. A trend for an effect of training on the relationship between Wpeak and ΔSmO<sub>2</sub>min was observed (<italic>p </italic>= 0.06).</p></sec><sec><title>Conclusion</title><p>This meta-analysis showed no effects of endurance training on SmO<sub>2</sub>min during an IET. Our results showed a trend for an effect of training on the relationship between Wpeak and ΔSmO<sub>2</sub>min, with no effect for V˙O<sub>2</sub>peak and ΔSmO<sub>2</sub>min. It is possible that SmO<sub>2</sub>min is not affected by endurance training, and may be used as a physiological marker for improvements in submaximal performance rather than at peak.</p></sec>