To examine the feasibility of using near-infrared spectroscopy (NIRS) for physiological threshold detection and whether NIRS-derived parameters differ between highly-trained and less-trained cyclists. Twenty-seven male cyclists were divided into: highly trained endurance cyclists (EA) and recreational cyclists (RA). Participants performed a step-incremental cycling test to exhaustion. Ventilatory thresholds (VT1 and VT2) were determined using gas-exchange variables. NIRS sensor was placed on the vastus lateralis muscle to identify breakpoints corresponding to ventilatory thresholds. No significant differences were observed between NIRS-derived thresholds, compared to VT1 and VT2 (F = 1.04-1.33, p = 0.26-0.36). Moderate to strong correlations were found between NIRS-derived thresholds and ventilatory thresholds (r = 0.65-0.9, p < 0.01). A moderate correlation was found between maximal oxygen uptake and minimal tissue saturation index (TSI) value during the test (r = - 0.411, p = 0.037). EA group showed tendency towards lower minimal TSI values compared to RA group (MD = 5.46% TSI, p = 0.081). NIRS is a feasible tool for non-invasive assessment of ventilatory thresholds during incremental exercise. TSI, in particular, showed lower variability compared to other NIRS-derived parameters, and may therefore be more suitable for practical applications in sport science. Highly trained athletes demonstrated distinct physiological responses compared to recreational athletes, suggesting enhanced peripheral oxygen extraction.

Faculty of Sport Studies Masaryk University 625 00 Brno Czech Republic

Faculty of Sport University of Ljubljana Ljubljana Slovenia

Science and Research Centre Koper Institute for Kinesiology Research Koper Slovenia

Citace poskytuje Crossref.org