Continuous Monitoring of Muscle Oxygenation in Endurance Athletes During Incremental Cycling: Experimental Validation of a Wearable Continuous-Wave NIRS Sensor Using Frequency-Domain Near-Infrared Spectroscopy
Year: 2025
Type: article
Abstract: Individuals often lack field-based tools to monitor exercise effectiveness. New sensing methods may allow for an improved measurement of the individualized response to exercise by monitoring oxygen kinetics directly in muscle tissue. This study aimed to validate a non-invasive wearable sensor capable of measuring muscle oxygen saturation (SmO2) using continuous wave near-infrared spectroscopy (CW-NIRS) against a laboratory-validated frequency-domain NIRS (FDNIRS) device. Ten physically fit adults performed an incremental cycling test until voluntary exhaustion. Devices were placed on contralateral rectus femoris muscles, respectively. SmO2 was simultaneously measured continuously for the duration of the protocol. Time series alignment and dataset resampling were performed to enable direct comparison. Z-score normalization accounted for inter-individual differences in a group-level analysis. Individual subject validation showed strong correlations between the two devices (r = 0.792, range: 0.69-0.88, p < 0.001) with an RMSD < 5% for most subjects, a mean bias of 0.005 and low proportional bias (-0.199) between all paired measurements. Group-level analysis demonstrated a correlation of r = 0.788. Bland-Altman analysis revealed 95% of all measurements fell between -8.1% to 7.6% SmO2. The CW-NIRS device delivered reliable performance compared to the FDNIRS device, offering potential applications for real-time physiological monitoring during exercise and performance assessment.
Source: Bioengineering
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,258
Award: G5472138960
OpenAlex ID: W4415560236