Muscle oxygen saturation rates coincide with lactate-based exercise thresholds

Reliability of threshold determination using portable muscle oxygenation monitors during exercise testing: a systematic review and meta-analysis

“…These results are in line with other studies that determined thresholds with non-portable NIRS in cycling 50 . Moreover, a fair ICC in running was shown (ICC = 0.23–0.49) 16 , 44 . 28/07/2023 17:06:00 A lower number of studies assessed the first threshold compared with the second one (3 vs. 12 studies), maybe due to the difficulty of determining the MOT 1, since the slope changes very slightly and the ICC value is not as good as the second threshold 42 .…”

“…Our meta-analyses were focused on showing whether the exercise intensity where the first and second thresholds were detected using the portable NIRS was more reliable than the gold standards methods (gas exchange and blood lactate). Table 1 shows how the relationship between MOT and VT was analyzed in 7 studies 16 , 25 , 39 – 43 and in 9 studies for LT 17 , 26 , 41 , 44 – 49 .…”

“…The second threshold was determined using the blood lactate concentration and muscle oxygenation in different sports such as cycling 16 , 17 , 46 – 48 , running 44 , 45 , 49 and rowing 26 . ICC values showed a certain disparity and were fair, moderate or good (ICC = 0.29–0.90) in studies of running, although cycling studies showed a good ICC (ICC = 0.91–0.94).…”

“…Despite recent research into the application of NIRS technology for the purpose of obtaining thresholds, there is a lack of research on its methods of determination. The articles included in this systematic review use different methods for determining thresholds: BSX Insight (20%, N = 3) 45 , 47 , 49 , double linear regression (46%, N = 7) 16 , 26 , 39 , 41 – 44 , visual method 17 , 25 , 40 , Dmax or modified Dmax 46 and applications of devices Humon Beta 48 .…”

Agreement between Ventilatory Thresholds and Bilaterally Measured Vastus Lateralis Muscle Oxygen Saturation Breakpoints in Trained Cyclists: Effects of Age and Performance

“…More working and non-locomotor muscle groups [ 12 ] would be needed to study with NIRS methods during different workloads in parallel with systemic response measurements, and exercise protocols with rest periods between more extended workloads [ 47 ] would probably be useful to use for threshold evaluation, to separate the effects of the fatigue and work rate. Also, different signal computation methods should be considered for SmO 2 threshold evaluation [ 47 ] to reduce methodological bias arising from signal fluctuation, especially during lower work rates. At the same time, the results of our study demonstrate that wearable NIRS-based devices can add interesting information for monitoring the endurance athlete’s training process, but they cannot be used as a replacement for classical threshold intensity measuring methods.…”