Aerobic Function and Muscle Deoxygenation Dynamics during Ramp Exercise in Children

It is typically assumed that in the context of double-leg cycling, dominant (DOMLEG) and nondominant legs (NDOMLEG) have similar aerobic capacity and both contribute equally to the whole body physiological responses. However, there is a paucity of studies that have systematically investigated maximal and submaximal aerobic performance and characterized the profiles of local muscle deoxygenation in relation to leg dominance. Using counterweighted single-leg cycling, this study explored whether peak O2 consumption (V̇o2peak), maximal lactate steady-state (MLSSp), and profiles of local deoxygenation [HHb] would be different in the DOMLEG compared with the NDOMLEG. Twelve participants performed a series of double-leg and counterweighted single-leg DOMLEG and NDOMLEG ramp-exercise tests and 30-min constant-load trials. V̇o2peak was greater in the DOMLEG than in the NDOMLEG (2.87 ± 0.42 vs. 2.70 ± 0.39 L/min, P < 0.05). The difference in V̇o2peak persisted even after accounting for lean mass ( P < 0.05). Similarly, MLSSp was greater in the DOMLEG than in the NDOMLEG (118 ± 31 vs. 109 ± 31 W; P < 0.05). Furthermore, the amplitude of the [HHb] signal during ramp exercise was larger in the DOMLEG than in the NDOMLEG during both double-leg (26.0 ± 8.4 vs. 20.2 ± 8.8 µM, P < 0.05) and counterweighted single-leg cycling (18.5 ± 7.9 vs. 14.9 ± 7.5 µM, P < 0.05). Additionally, the amplitudes of the [HHb] signal were highly to moderately correlated with the mode-specific V̇o2peak values (ranging from 0.91 to 0.54). These findings showed in a group of young men that maximal and submaximal aerobic capacities were greater in the DOMLEG than in the NDOMLEG and that superior peripheral adaptations of the DOMLEG may underpin these differences.

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Impaired Aerobic Function in Patients with Cystic Fibrosis during Ramp Exercise

Medicine & Science in Sports & Exercise ◽

10.1249/mss.0000000000000369 ◽

2014 ◽

Vol 46 (12) ◽

pp. 2271-2278 ◽

Cited By ~ 14

Author(s):

ZOE LOUISE SAYNOR ◽

ALAN ROBERT BARKER ◽

PATRICK JOHN OADES ◽

CRAIG ANTHONY WILLIAMS

Keyword(s):

Cystic Fibrosis ◽

Aerobic Function ◽

Ramp Exercise

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The relationship between muscle deoxygenation and activation in different muscles of the quadriceps during cycle ramp exercise

Journal of Applied Physiology ◽

10.1152/japplphysiol.01216.2010 ◽

2011 ◽

Vol 111 (5) ◽

pp. 1259-1265 ◽

Cited By ~ 56

Author(s):

Lisa M. K. Chin ◽

John M. Kowalchuk ◽

Thomas J. Barstow ◽

Narihiko Kondo ◽

Tatsuro Amano ◽

...

Keyword(s):

Muscle Activation ◽

Near Infrared ◽

Vastus Lateralis ◽

Young Male ◽

Rectus Femoris ◽

Work Rate ◽

Sigmoid Function ◽

Muscle Deoxygenation ◽

Ramp Exercise ◽

The Relationship

The relationship between muscle deoxygenation and activation was examined in three different muscles of the quadriceps during cycling ramp exercise. Seven young male adults (24 ± 3 yr; mean ± SD) pedaled at 60 rpm to exhaustion, with a work rate (WR) increase of 20 W/min. Pulmonary oxygen uptake was measured breath-by-breath, while muscle deoxygenation (HHb) and activity were measured by time-resolved near-infrared spectroscopy (NIRS) and surface electromyography (EMG), respectively, at the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). Muscle deoxygenation was corrected for adipose tissue thickness and normalized to the amplitude of the HHb response, while EMG signals were integrated (iEMG) and normalized to the maximum iEMG determined from maximal voluntary contractions. Muscle deoxygenation and activation were then plotted as a percentage of maximal work rate (%WRmax). The HHb response for all three muscle groups was fitted by a sigmoid function, which was determined as the best fitting model. The c/d parameter for the sigmoid fit (representing the %WRmax at 50% of the total amplitude of the HHb response) was similar between VL (47 ± 12% WRmax) and VM (43 ± 11% WRmax), yet greater ( P < 0.05) for RF (65 ± 13% WRmax), demonstrating a “right shift” of the HHb response compared with VL and VM. The iEMG also showed that muscle activation of the RF muscle was lower ( P < 0.05) compared with VL and VM throughout the majority of the ramp exercise, which may explain the different HHb response in RF. Therefore, these data suggest that the sigmoid function can be used to model the HHb response in different muscles of the quadriceps; however, simultaneous measures of muscle activation are also needed for the HHb response to be properly interpreted during cycle ramp exercise.

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A Comparative Analysis on Cardiovascular disease risk factors and aerobic function of women according to age group

Korean Journal of Sports Science ◽

10.35159/kjss.2017.08.26.4.955 ◽

2017 ◽

Vol 26 (4) ◽

pp. 955-962

Author(s):

Yoo-Jin Shim ◽

A-Ram Kim ◽

Kyu-Tae Kim

Keyword(s):

Risk Factors ◽

Cardiovascular Disease ◽

Comparative Analysis ◽

Disease Risk ◽

Cardiovascular Disease Risk ◽

Cardiovascular Disease Risk Factors ◽

Age Group ◽

Aerobic Function

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Kinetics of muscle deoxygenation and microvascular Po2 during contractions in rat: comparison of optical spectroscopy and phosphorescence-quenching techniques

Journal of Applied Physiology ◽

10.1152/japplphysiol.00925.2011 ◽

2012 ◽

Vol 112 (1) ◽

pp. 26-32 ◽

Cited By ~ 45

Author(s):

Shunsaku Koga ◽

Yutaka Kano ◽

Thomas J. Barstow ◽

Leonardo F. Ferreira ◽

Etsuko Ohmae ◽

...

Keyword(s):

Infrared Spectroscopy ◽

Visible Light ◽

Near Infrared Spectroscopy ◽

Near Infrared ◽

Fiber Type ◽

Type I ◽

Phosphorescence Quenching ◽

Mean Response Time ◽

Muscle Deoxygenation ◽

Visible Light Spectroscopy

The overarching presumption with near-infrared spectroscopy measurement of muscle deoxygenation is that the signal reflects predominantly the intramuscular microcirculatory compartment rather than intramyocyte myoglobin (Mb). To test this hypothesis, we compared the kinetics profile of muscle deoxygenation using visible light spectroscopy (suitable for the superficial fiber layers) with that for microvascular O2 partial pressure (i.e., PmvO2, phosphorescence quenching) within the same muscle region (0.5∼1 mm depth) during transitions from rest to electrically stimulated contractions in the gastrocnemius of male Wistar rats ( n = 14). Both responses could be modeled by a time delay (TD), followed by a close-to-exponential change to the new steady level. However, the TD for the muscle deoxygenation profile was significantly longer compared with that for the phosphorescence-quenching PmvO2 [8.6 ± 1.4 and 2.7 ± 0.6 s (means ± SE) for the deoxygenation and PmvO2, respectively; P < 0.05]. The time constants (τ) of the responses were not different (8.8 ± 4.7 and 11.2 ± 1.8 s for the deoxygenation and PmvO2, respectively). These disparate (TD) responses suggest that the deoxygenation characteristics of Mb extend the TD, thereby increasing the duration (number of contractions) before the onset of muscle deoxygenation. However, this effect was insufficient to increase the mean response time. Somewhat differently, the muscle deoxygenation response measured using near-infrared spectroscopy in the deeper regions (∼5 mm depth) (∼50% type I Mb-rich, highly oxidative fibers) was slower (τ = 42.3 ± 6.6 s; P < 0.05) than the corresponding value for superficial muscle measured using visible light spectroscopy or PmvO2 and can be explained on the basis of known fiber-type differences in PmvO2 kinetics. These data suggest that, within the superficial and also deeper muscle regions, the τ of the deoxygenation signal may represent a useful index of local O2 extraction kinetics during exercise transients.

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Time-course of V̇O2 kinetics responses during moderate-intensity exercise subsequent to HIIT vs moderate-intensity continuous training in type 2 diabetes.

Journal of Applied Physiology ◽

10.1152/japplphysiol.00952.2020 ◽

2021 ◽

Author(s):

Norita Gildea ◽

Adam McDermott ◽

Joel Rocha ◽

Donal O'Shea ◽

Simon Green ◽

...

Keyword(s):

Type 2 Diabetes ◽

Time Course ◽

Near Infrared ◽

Vastus Lateralis ◽

Moderate Intensity ◽

Vastus Lateralis Muscle ◽

Maximal Heart Rate ◽

Continuous Training ◽

Muscle Deoxygenation

We assessed the time course of changes in oxygen uptake (V̇O2) and muscle deoxygenation (i.e., deoxygenated haemoglobin and myoglobin, [HHb+Mb]) kinetics during transitions to moderate-intensity cycling following 12-weeks of low-volume high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) in adults with type 2 diabetes (T2D). Participants were randomly assigned to MICT (n=10, 50 min of moderate-intensity cycling), HIIT (n=9, 10x1 min at ~90% maximal heart rate) or non-exercising control (n=9) groups. Exercising groups trained 3 times per week and measurements were taken every 3 weeks. [HHb+Mb] kinetics were measured by near-infrared spectroscopy at the vastus lateralis muscle. The local matching of O2 delivery to O2 utilization was assessed by the Δ[HHb+Mb]/ΔV̇O2ratio. The pretraining time constant of the primary phase of V̇O2 (τV̇O2p ) decreased (P<0.05) at wk 3 of training in both MICT (from 44±12 to 32±5 s) and HIIT (from 42±8 to 32 ± 4 s) with no further changes thereafter; while no changes were reported in controls. The pretraining overall dynamic response of muscle deoxygenation (τ'[HHb+Mb]) was faster than τV̇O2p in all groups, resulting in Δ[HHb+Mb]/V̇O2p showing a transient "overshoot" relative to the subsequent steady-state level. After 3 wks, the Δ[HHb+Mb]/V̇O2p overshoot was eliminated only in the training groups, so that τ'[HHb+Mb] was not different to τV̇O2p in MICT and HIIT. The enhanced V̇O2 kinetics response consequent to both MICT and HIIT in T2D was likely attributed to a training-induced improvement in matching of O2 delivery to utilization.

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