Bilateral NIRS measurements of muscle mitochondrial capacity: Feasibility and repeatability

Abstract

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Near-InfraRed Spectroscopy Provides a Reproducible Estimate of Muscle Aerobic Capacity, but Not Whole-Body Aerobic Power

“…The obtained ICC and CVs for day-to-day variability of vastus lateralis NIRS-derived mitochondrial power in our present study are of quite similar magnitude and strength to those reported by Hanna et al [20], Pilotto et al [28], Fennel et al [23], Beever et al [14], and Ryan et al [10], investigating the same muscle on slightly different populations and using other protocols. Additionally, the CVs of the between-day time and/or rate constants of oxygen recovery kinetics have been reported to be quite similar for another leg muscle frequently investigated, the gastrocnemius [10,12,24,34].…”

“…Recreationally active young adult men (n = 11; 28.1 ± 9.7 y; 181.5 ± 6.0 cm; 79.8 ± 14.1 kg; BMI 24.1 ± 3.0; skin color type: 1 to 2 on a 5-point scale) were recruited for this study. The number of participants was chosen based on the quantity of participants recruited in similar studies (n = 10-17) [10,20,26]. This facilitates direct comparisons between studies.…”

“…NIRS variables (i.e., recovery of oxyhemoglobin [HbO 2 ], deoxyhemoglobin [HHb], or calculated tissue saturation index) have been investigated for different limb muscles including plantar flexors [10][11][12][13][14][15][16][17][18][19], plantar extensors [16], knee extensors [10,20], knee flexors [20], wrist flexors [11,17], and some other superficial small muscles [13] in different age and gender populations ranging from completely inactive [21] to highly trained individuals [22,23]. Many of these studies addressed the day-to-day reproducibility of the markers of mitochondria capacity and generated varying but overall promising results, especially those highlighted in more recent publications [20,24,25].…”

“…However, even with this increasingly widespread application, the methodology is far from robustly established yet, and further improvements are sought. For instance, before muscular oxygen kinetics are measured using NIRS and mitochondrial power is estimated, metabolic activation of the muscle is achieved with voluntary muscle contraction [9,26] or electrical stimulation [20], and recently, even the possibility of not activating the muscle by any contractions preceding the measurements has been proposed [27]. Some studies have been designed to intentionally cover a wide range of aerobic fitness of the participants, e.g., [13,15,17], making it questionable the reliability and validity of the methodology in more relevant settings of less heterogeneous groups as those meeting the physical activity guidelines.…”

Oxyhemoglobin Concentration and Oxygen Uptake Signal During Recovery From Exhaustive Exercise in Healthy Subjects—Relationship With Aerobic Capacity

“…Further, in the last decade protocols for estimating oxidative capacity of the skeletal muscle utilizing NIRS have been developed and validated. These techniques are well suited to monitor changes in muscle specific aerobic adaptations over time and thus, may enable the evaluation of the effectiveness of interventions at the muscular level (Hanna et al, 2021). Further, associations between the oxidative metabolism of the gastrocnemius muscle, utilizing NIRS during an arterial occlusion protocol, and whole-body VO 2peak have been shown (Lagerwaard et al, 2019).…”