Determination of respiratory point compensation in healthy adults: Can non-invasive near-infrared spectroscopy help?

Fontana, Federico Y.; Keir, Daniel A.; Bellotti, Cecilia; Roia, Gabriela Fernanda De; Murias, Juan M.; Pogliaghi, Silvia

doi:10.1016/j.jsams.2014.07.016

Cited by 54 publications

(66 citation statements)

References 24 publications

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“…In general, data regarding V′O 2@RCP (%V′O 2peak ) are less well established compared to V′O 2@VAT (%V′O 2peak ). The V′O 2@RCP (%V′O 2peak ) identified is in accordance with previous reports [ 42 , 46 , 47 ]. The lower proportion of subjects whose RCP could be identified on the RATT than the cycle or the treadmill may reflect that the RATT is less consistent in provoking cardiorespiratory loads high enough to reach RCP.…”

Section: Discussionsupporting

confidence: 92%

Submaximal cardiopulmonary thresholds on a robotics-assisted tilt table, a cycle and a treadmill: a comparative analysis

et al. 2015

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BackgroundThe robotics-assisted tilt table (RATT), including actuators for tilting and cyclical leg movement, is used for rehabilitation of severely disabled neurological patients. Following further engineering development of the system, i.e. the addition of force sensors and visual bio-feedback, patients can actively participate in exercise testing and training on the device. Peak cardiopulmonary performance parameters were previously investigated, but it also important to compare submaximal parameters with standard devices. The aim of this study was to evaluate the feasibility of the RATT for estimation of submaximal exercise thresholds by comparison with a cycle ergometer and a treadmill.Methods17 healthy subjects randomly performed six maximal individualized incremental exercise tests, with two tests on each of the three exercise modalities. The ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) were determined from breath-by-breath data.ResultsVAT and RCP on the RATT were lower than the cycle ergometer and the treadmill: oxygen uptake (V′O2) at VAT was [mean (SD)] 1.2 (0.3), 1.5 (0.4) and 1.6 (0.5) L/min, respectively (p < 0.001); V′O2 at RCP was 1.7 (0.4), 2.3 (0.8) and 2.6 (0.9) L/min, respectively (p = 0.001). High correlations for VAT and RCP were found between the RATT vs the cycle ergometer and RATT vs the treadmill (R on the range 0.69–0.80). VAT and RCP demonstrated excellent test–retest reliability for all three devices (ICC from 0.81 to 0.98). Mean differences between the test and retest values on each device were close to zero. The ventilatory equivalent for O2 at VAT for the RATT and cycle ergometer were similar and both were higher than the treadmill. The ventilatory equivalent for CO2 at RCP was similar for all devices. Ventilatory equivalent parameters demonstrated fair-to-excellent reliability and repeatability.ConclusionsIt is feasible to use the RATT for estimation of submaximal exercise thresholds: VAT and RCP on the RATT were lower than the cycle ergometer and the treadmill, but there were high correlations between the RATT vs the cycle ergometer and vs the treadmill. Repeatability and test–retest reliability of all submaximal threshold parameters from the RATT were comparable to those of standard devices.

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Section: Discussionsupporting

confidence: 92%

Submaximal cardiopulmonary thresholds on a robotics-assisted tilt table, a cycle and a treadmill: a comparative analysis

et al. 2015

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“…This attenuation in the [HHb] signal is suggestive of a lower reliance on O 2 extraction at the level of the working muscles (specifically the muscle portion interrogated by the NIRS probe), despite the O 2 consumption (

O 2 ) continuing to rise along with the increments in power output (PO). The point at which the linearity of the increase in the [HHb] signal is disrupted has been described as a breakpoint ([HHb] BP ) (Spencer et al, 2012 ), and it has been shown to occur at a metabolic rate (i.e.,

O 2 ) similar to the respiratory compensation point (RCP) (Murias et al, 2013b ; Fontana et al, 2015 ; Keir et al, 2015 ; Iannetta et al, 2017 ) and the electromyography (EMG) threshold (EMG t ) (Hug et al, 2003a , b ; Osawa et al, 2011 ; Racinais et al, 2014 ). Interestingly, Boone et al ( 2016 ) recently suggested that, at least in the vastus lateralis (VL) muscle, a cascade of events may occur as the EMG t was found to precede the RCP which in turn preceded the [HHb] BP .…”

Section: Introductionmentioning

confidence: 99%

“…Given that the occurrence of the [HHb] BP during RI tests has been only examined in the VL muscle (Spencer et al, 2012 ; Murias et al, 2013a , b ; Fontana et al, 2015 ; Boone et al, 2016 ; Iannetta et al, 2017 ), it is unknown whether the same behavior in the dynamic adjustment of the [HHb] signal would be observed in other muscles involved in cycling, such as the vastus medialis (VM) and the rectus femoris (RF). This is an important issue that needs to be addressed as it is likely that due to differences in perfusive and diffusive capacity (Poole et al, 2013 ), muscle fiber composition (Johnson et al, 1973 ), patterns of muscle recruitment (Chin et al, 2011 ) as well as differences in aerobic fitness (Boone et al, 2009 ), regional heterogeneities in muscle blood flow (Q m ) and muscle

O 2 (

O 2m ), and activation (Hug, 2010 ; Okushima et al, 2015 ) may affect the correspondence between the [HHb] BP and EMG t with the RCP.…”

Section: Introductionmentioning

confidence: 99%

Quadriceps Muscles O2 Extraction and EMG Breakpoints during a Ramp Incremental Test

et al. 2017

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Muscle deoxygenated breakpoint ([HHb]BP) has been found to be associated with other indices of exercise tolerance in the vastus lateralis (VL) muscle but not in the vastus medialis (VM) and rectus femoris (RF).Purpose: To investigate whether the [HHb]BP occurs also in the VM and RF muscles and whether or not it is associated with other physiological indices of exercise tolerance, such as the EMG threshold (EMGt) and the respiratory compensation point (RCP).Methods: Twelve young endurance trained participants performed maximal ramp incremental (RI) cycling tests (25–30 W·min−1 increments). Muscle oxygen extraction and activity as well as ventilatory and gas exchange parameters were measured. After accounting for the mean response time, the oxygen uptake (trueV·O2) corresponding to the RCP, [HHb]BP, and the EMGt was determined.Results: Peak power output (POpeak) was 359 ± 48 W. Maximal oxygen consumption (trueV·O2max) was 3.87 ± 0.46 L·min−1. The trueV·O2 at the RCP was 3.39 ± 0.41 L·min−1. The trueV·O2 (L·min−1) corresponding to the [HHb]BP and EMGt were: 3.49 ± 0.46 and 3.40 ± 0.44; 3.44 ± 0.61 and 3.43 ± 0.49; 3.59 ± 0.52, and 3.48 ± 0.46 for VL, VM, and RF, respectively. Pearson's correlation between these thresholds ranged from 0.90 to 0.97 (P < 0.05). No difference was found for the absolute trueV·O2 and the normalized PO (%) at which the thresholds occurred in all three muscles investigated (P > 0.05). Although in eight out of 12 participants, the [HHb]BP in the RF led to a steeper increase instead of leading to a plateau-like response as observed in the VL and VM, the trueV·O2 at the breakpoints still coincided with that at the RCP.Conclusions: This study demonstrated that local indices of exercise tolerance derived from different portions of the quadriceps are not different to the systemic index of the RCP.

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“…These NIRS signals present multiple breakpoints during incremental exercise. For instance, the [HHbMb] breakpoint during ramp exercise is suggested to resemble an upper limit of fractional oxygen extraction in the exercising leg muscles during incremental exercise [ 9 – 11 ] and approximates VT2 [ 10 , 12 , 11 , 13 – 15 ], maximal lactate steady state [ 14 , 16 ] and critical power [ 14 ]. At somewhat lower exercise intensities, a breakpoint in Hb difference ([O 2 HbMb-HHbMb]) occurs during maximal stepwise incremental exercise and shows high correlations with VT1 and the lactate threshold (r>0.88) [ 17 – 19 ].…”

Section: Introductionmentioning

confidence: 99%

Oxygenation Threshold Derived from Near-Infrared Spectroscopy: Reliability and Its Relationship with the First Ventilatory Threshold

et al. 2016

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BackgroundNear-infrared spectroscopy (NIRS) measurements of oxygenation reflect O2 delivery and utilization in exercising muscle and may improve detection of a critical exercise threshold.PurposeFirst, to detect an oxygenation breakpoint (Δ[O2HbMb-HHbMb]-BP) and compare this breakpoint to ventilatory thresholds during a maximal incremental test across sexes and training status. Second, to assess reproducibility of NIRS signals and exercise thresholds and investigate confounding effects of adipose tissue thickness on NIRS measurements.MethodsForty subjects (10 trained male cyclists, 10 trained female cyclists, 11 endurance trained males and 9 recreationally trained males) performed maximal incremental cycling exercise to determine Δ[O2HbMb-HHbMb]-BP and ventilatory thresholds (VT1 and VT2). Muscle haemoglobin and myoglobin O2 oxygenation ([HHbMb], [O2HbMb], SmO2) was determined in m. vastus lateralis. Δ[O2HbMb-HHbMb]-BP was determined by double linear regression. Trained cyclists performed the maximal incremental test twice to assess reproducibility. Adipose tissue thickness (ATT) was determined by skinfold measurements.ResultsΔ[O2HbMb-HHbMb]-BP was not different from VT1, but only moderately related (r = 0.58–0.63, p<0.001). VT1 was different across sexes and training status, whereas Δ[O2HbMb-HHbMb]-BP differed only across sexes. Reproducibility was high for SmO2 (ICC = 0.69–0.97), Δ[O2HbMb-HHbMb]-BP (ICC = 0.80–0.88) and ventilatory thresholds (ICC = 0.96–0.99). SmO2 at peak exercise and at occlusion were strongly related to adipose tissue thickness (r2 = 0.81, p<0.001; r2 = 0.79, p<0.001). Moreover, ATT was related to asymmetric changes in Δ[HHbMb] and Δ[O2HbMb] during incremental exercise (r = -0.64, p<0.001) and during occlusion (r = -0.50, p<0.05).ConclusionAlthough the oxygenation threshold is reproducible and potentially a suitable exercise threshold, VT1 discriminates better across sexes and training status during maximal stepwise incremental exercise. Continuous-wave NIRS measurements are reproducible, but strongly affected by adipose tissue thickness.

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Determination of respiratory point compensation in healthy adults: Can non-invasive near-infrared spectroscopy help?

Cited by 54 publications

References 24 publications

Submaximal cardiopulmonary thresholds on a robotics-assisted tilt table, a cycle and a treadmill: a comparative analysis

Submaximal cardiopulmonary thresholds on a robotics-assisted tilt table, a cycle and a treadmill: a comparative analysis

Quadriceps Muscles O2 Extraction and EMG Breakpoints during a Ramp Incremental Test

Oxygenation Threshold Derived from Near-Infrared Spectroscopy: Reliability and Its Relationship with the First Ventilatory Threshold

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