Muscle Oxygenation Kinetics Research Articles

Soothing the sleeping giant: improving skeletal muscle oxygen kinetics and exercise intolerance in HFpEF.

Patients with heart failure with preserved ejection fraction (HFpEF) have similar degrees of exercise intolerance and dyspnea as patients with heart failure with reduced EF (HFrEF). The underlying pathophysiology leading to impaired exertional ability in the HFpEF syndrome is not completely understood, and a growing body of evidence suggests "peripheral," i.e., noncardiac, factors may play an important role. Changes in skeletal muscle function (decreased muscle mass, capillary density, mitochondrial volume, and phosphorylative capacity) are common findings in HFrEF. While cardiac failure and decreased cardiac reserve account for a large proportion of the decline in oxygen consumption in HFrEF, impaired oxygen diffusion and decreased skeletal muscle oxidative capacity can also hinder aerobic performance, functional capacity and oxygen consumption (V̇o2) kinetics. The impact of skeletal muscle dysfunction and abnormal oxidative capacity may be even more pronounced in HFpEF, a disease predominantly affecting the elderly and women, two demographic groups with a high prevalence of sarcopenia. In this review, we 1) describe the basic concepts of skeletal muscle oxygen kinetics and 2) evaluate evidence suggesting limitations in aerobic performance and functional capacity in HFpEF subjects may, in part, be due to alterations in skeletal muscle oxygen delivery and utilization. Improving oxygen kinetics with specific training regimens may improve exercise efficiency and reduce the tremendous burden imposed by skeletal muscle upon the cardiovascular system.

Muscle oxygen changes following Sprint Interval Cycling training in elite field hockey players.

This study examined the effects of Sprint Interval Cycling (SIT) on muscle oxygenation kinetics and performance during the 30-15 intermittent fitness test (IFT). Twenty-five women hockey players of Olympic standard were randomly selected into an experimental group (EXP) and a control group (CON). The EXP group performed six additional SIT sessions over six weeks in addition to their normal training program. To explore the potential training-induced change, EXP subjects additionally completed 5 x 30s maximal intensity cycle testing before and after training. During these tests near-infrared spectroscopy (NIRS) measured parameters; oxyhaemoglobin + oxymyoglobin (HbO2+ MbO2), tissue deoxyhaemoglobin + deoxymyoglobin (HHb+HMb), total tissue haemoglobin (tHb) and tissue oxygenation (TSI %) were taken. In the EXP group (5.34±0.14 to 5.50±0.14m.s-1) but not the CON group (pre = 5.37±0.27 to 5.39±0.30m.s-1) significant changes were seen in the 30-15IFT performance. EXP group also displayed significant post-training increases during the sprint cycling: ΔTSI (−7.59±0.91 to −12.16±2.70%); ΔHHb+HMb (35.68±6.67 to 69.44±26.48μM.cm); and ΔHbO2+ MbO2 (−74.29±13.82 to −109.36±22.61μM.cm). No significant differences were seen in ΔtHb (−45.81±15.23 to −42.93±16.24). NIRS is able to detect positive peripheral muscle oxygenation changes when used during a SIT protocol which has been shown to be an effective training modality within elite athletes.

Physiological characteristics of well-trained junior sprint kayak athletes.

This study aimed to profile the physiological characteristics of junior sprint kayak athletes (n=21, VO2max 4.1±0.7 L/min, training experience 2.7±1.2 y) and to establish the relationship between physiological variables (VO2max, VO2 kinetics, muscle-oxygen kinetics, paddling efficiency) and sprint kayak performance. VO2max, power at VO2max, power:weight ratio, paddling efficiency, VO2 at lactate threshold, and whole-body and muscle oxygen kinetics were determined on a kayak ergometer in the laboratory. Separately, on-water time trials (TT) were completed over 200 m and 1000 m. Large to nearly perfect (-.5 to -.9) inverse relationships were found between the physiological variables and on-water TT performance across both distances. Paddling efficiency and lactate threshold shared moderate to very large correlations (-.4 to -.7) with 200- and 1000-m performance. In addition, trivial to large correlations (-.11 to -.5) were observed between muscle-oxygenation parameters, muscle and whole-body oxygen kinetics, and performance. Multiple regression showed that 88% of the unadjusted variance for the 200-m TT performance was explained by VO2max, peripheral muscle deoxygenation, and maximal aerobic power (P<.001), whereas 85% of the unadjusted variance in 1000-m TT performance was explained by VO2max and deoxyhemoglobin (P<.001). The current findings show that well-trained junior sprint kayak athletes possess a high level of relative aerobic fitness and highlight the importance of the peripheral muscle metabolism for sprint kayak performance, particularly in 200-m races, where finalists and nonfinalists are separated by very small margins. Such data highlight the relative aerobic-fitness variables that can be used as benchmarks for talent-identification programs or monitoring longitudinal athlete development. However, such approaches need further investigation.

Relationship between Muscle Oxygenation Kinetics and Tolerance to Fatigue on Short-term Isometric Knee Extension Exercise

Relationship between Muscle Oxygenation Kinetics and Tolerance to Fatigue on Short-term Isometric Knee Extension Exercise

Respiratory and locomotor muscle blood-volume and oxygenation kinetics during intense intermittent exercise

In this study, we examined the time course of changes in the blood volume and oxygenation of accessory respiratory (RM) and locomotor (LM) muscles, and the interrelationships of changes in these parameters during maximal incremental intermittent exercise in 15 non-endurance-trained active men. Blood volume and oxygenation of the serratus anterior and of vastus lateralis were measured simultaneously by near-infrared spectroscopy. The respiratory compensation point, and the breakpoints where abrupt changes were apparent in RM and LM blood volume and oxygenation versus time were identified. During exercise, the decreases in RM and LM oxygenation were accentuated in the vicinity of the respiratory compensation point. This was concomitant with a reduction in LM, but not RM, blood volume. The time at which the respiratory compensation point and the breakpoints in RM and LM blood volume and oxygenation were detected (70.2–75.0% exercise time) did not differ, and were inter-correlated (r=0.56 to 0.95). Moreover, the rate of the accelerated fall of oxygenation in the locomotor muscles was correlated with that of the decline in blood volume in that area (r=0.73), and with that of the accelerated fall of oxygenation in the respiratory muscles (r=0.71). The results suggest that the high ventilatory demand, which occurs naturally during intense intermittent exercise in non-endurance-trained individuals, may precipitate an accelerated fall in RM oxygenation, concomitant with a reduction in LM blood volume and an accentuated decline in LM oxygenation. Such responses are likely to occur above the respiratory compensation point during intermittent exercise.

Performance and physiological responses during a sprint interval training session: relationships with muscle oxygenation and pulmonary oxygen uptake kinetics

The purpose of this study was to examine the cardiorespiratory and muscle oxygenation responses to a sprint interval training (SIT) session, and to assess their relationships with maximal pulmonary O(2) uptake [Formula: see text], on- and off- [Formula: see text] kinetics and muscle reoxygenation rate (Reoxy rate). Ten male cyclists performed two 6-min moderate-intensity exercises (≈90-95% of lactate threshold power output, Mod), followed 10 min later by a SIT session consisting of 6 × 30-s all out cycling sprints interspersed with 2 min of passive recovery. [Formula: see text] kinetics at Mod onset ([Formula: see text]) and cessation ([Formula: see text]) were calculated. Cardiorespiratory variables, blood lactate ([La](b)) and muscle oxygenation level of the vastus lateralis (tissue oxygenation index, TOI) were recorded during SIT. Percentage of the decline in power output (%Dec), time spent above 90% of [Formula: see text] (t > 90% [Formula: see text]) and Reoxy rate after each sprint were also recorded. Despite a low mean [Formula: see text] (48.0 ± 4.1% of [Formula: see text]), SIT performance was associated with high peak [Formula: see text] (90.4 ± 2.8% of [Formula: see text]), muscle deoxygenation (sprint ΔTOI = -27%) and [La](b) (15.3 ± 0.7 mmol l(-1)) levels. Muscle deoxygenation and Reoxy rate increased throughout sprint repetitions (P < 0.001 for both). Except for t > 90% [Formula: see text] versus [Formula: see text] [r = 0.68 (90% CL, 0.20; 0.90); P = 0.03], there were no significant correlations between any index of aerobic function and either SIT performance or physiological responses [e.g., %Dec vs. [Formula: see text]: r = -0.41 (-0.78; 0.18); P = 0.24]. Present results show that SIT elicits a greater muscle O(2) extraction with successive sprint repetitions, despite the decrease in external power production (%Dec = 21%). Further, our findings obtained in a small and homogenous group indicate that performance and physiological responses to SIT are only slightly influenced by aerobic fitness level in this population.

Different Gripping Intervals in Reproducibility of Force-Decreasing Curve and Muscle Oxygenation Kinetics during Sustained Maximal Gripping

The purpose was to examine the properties and reproducibility of the force-decreasing curve and muscle-oxygenation kinetics measured by near infrared spectroscopy in sustained isometric grip and rhythmic repeated grip measurements using various contraction intervals (2 to 5 sec.). 10 healthy young adults performed both grip tests for 6 min., during which muscle-oxygenation kinetics were measured. The intraclass correlation coefficients of the time to reach the minimum value for oxygenated hemoglobin and myoglobin tended to become lower with longer relaxation time, especially over a 3-sec. interval. Although blood-flow obstruction closely influences the initial decreasing grip force during both grip tests with a 2-sec. interval, the decreasing grip force during rhythmic repeated gripping with over a 3-sec. interval is low. Hence, the physiological mechanism related to rhythmic repeated grip with over a 3-sec. interval may differ from that related to sustained isometric grip and rhythmic repeated grip with a 2-sec. interval.

Frequent low‐load ischemic resistance exercise to failure enhances muscle oxygen delivery and endurance capacity

This study investigated the effects of frequent low-load ischemic resistance exercise performed to failure on quadriceps size and performance, muscle activation, oxygen kinetics and cardiovascular responses. Ten healthy males performed knee-extension exercise for 4 weeks (4 sessions/week) at 15% maximal voluntary muscle contraction (MVC). One leg was trained with free blood flow (C-leg) while in the other leg (I-leg) ischemia was induced by an inflatable cuff (≥230 mmHg). Quadriceps cross-sectional area (CSA) of the I-leg increased by 3.4% (P<0.05). A tendency for smaller increase in muscle CSAs at the cuff level was observed. MVC force did not change in either leg, whereas the number of repetitions during exercise test to failure increased (P<0.01) by 63% in I-leg and 36% in C-leg. The decrease in muscle oxygenated hemoglobin concentration acquired by NIRS was attenuated (P<0.01) by 56% in I-leg and 21% in C-leg. Electromyographic amplitude of rectus femoris in I-leg was ∼45% lower (P<0.025) during the ischemic test. Also, ∼9% increase (P<0.05) in pre-exercise diastolic pressure was observed. In conclusion, substantial gains in muscle endurance capacity were induced, which were associated with enhanced muscle oxygen delivery. The potential negative effects of ischemic exercise with high cuff pressure on muscle and nerve and on arterial pressure regulation need further investigation.

Commentaries on Viewpoint: Do oxidative and anaerobic energy production in exercising muscle change throughout growth and maturation?

Commentaries on Viewpoint: Do oxidative and anaerobic energy production in exercising muscle change throughout growth and maturation?

Age‐ and sex‐related differences in muscle phosphocreatine and oxygenation kinetics during high‐intensity exercise in adolescents and adults

The aim of this investigation was to examine the adaptation of the muscle phosphates (e.g. phosphocreatine (PCr) and ADP) implicated in regulating oxidative phosphorylation, and oxygenation at the onset of high intensity exercise in children and adults. The hypotheses were threefold: primary PCr kinetics would be faster in children than adults; the amplitude of the PCr slow component would be attenuated in children; and the amplitude of the deoxyhaemoglobin/myoglobin (HHb) slow component would be reduced in children. Eleven children (5 girls, 6 boys, 13 +/- 1 years) and 11 adults (5 women, 6 men, 24 +/- 4 years) completed two to four constant work rate exercise tests within a 1.5 T MR scanner. Quadriceps muscle energetics during high intensity exercise were monitored using (31)P-MRS. Muscle oxygenation was monitored using near-infrared spectroscopy. The time constant for the PCr response was not significantly different in boys (31 +/- 10 s), girls (31 +/- 10 s), men (44 +/- 20 s) or women (29 +/- 14 s, main effects: age, p = 0.37, sex, p = 0.25). The amplitude of the PCr slow component relative to end-exercise PCr was not significantly different between children (23 +/- 23%) and adults (17 +/- 13%, p = 0.47). End-exercise [PCr] was significantly lower, and [ADP] higher, in females (18 +/- 4 mM and 53 +/- 16 microM) than males (23 +/- 4 mM, p = 0.02 and 37 +/- 11 microM, p = 0.02), but did not differ with age ([PCr]: p = 0.96, [ADP]: p = 0.72). The mean response time for muscle tissue deoxygenation was significantly faster in children (22 +/- 4 s) than adults (27 +/- 7 s, p = 0.01). The results of this study show that the control of oxidative metabolism at the onset of high intensity exercise is adult-like in 13-year-old children, but that matching of oxygen delivery to extraction is more precise in adults.

The influence of priming exercise on oxygen uptake, cardiac output, and muscle oxygenation kinetics during very heavy-intensity exercise in 9- to 13-yr-old boys

The present study examined the effect of priming exercise on O(2) uptake (Vo(2)) kinetics during subsequent very heavy exercise in eight 9- to 13-yr-old boys. We hypothesised that priming exercise would 1) elevate muscle O(2) delivery prior to the subsequent bout of very heavy exercise, 2) have no effect on the phase II Vo(2) tau, 3) elevate the phase II Vo(2) total amplitude, and 4) reduce the magnitude of the Vo(2) slow component. Each participant completed repeat 6-min bouts of very heavy-intensity cycling exercise separated by 6 min of light pedaling. During the tests Vo(2), muscle oxygenation (near infrared spectroscopy), and cardiac output (Q) (thoracic impedance) were determined. Priming exercise increased baseline muscle oxygenation and elevated Q at baseline and throughout the second exercise bout. The phase II Vo(2) tau was not altered by priming exercise (bout 1: 22 + or - 7 s vs. bout 2: 20 + or - 4 s; P = 0.30). However, the time constant describing the entire Vo(2) response from start to end of exercise was accelerated (bout 1: 43 + or - 8 s vs. bout 2: 36 + or - 5 s; P = 0.002) due to an increased total phase II Vo(2) amplitude (bout 1: 1.73 + or - 0.33 l/min vs. bout 2: 1.80 + or - 0.59 l/min; P = 0.002) and a reduced Vo(2) slow component amplitude (bout 1: 0.18 + or - 0.08 l/min vs. bout 2: 0.12 + or - 0.09 l/min; P = 0.048). These results suggest that phase II Vo(2) kinetics in young boys is principally limited by intrinsic muscle metabolic factors, whereas the Vo(2) total phase II and slow component amplitudes may be O(2) delivery sensitive.

Influence of Instruction Conditions on the Evaluation of Muscular Endurance Based on Muscle Oxygenation

Proper instruction is essential for evaluating muscular endurance with high reliability. This study aimed to examine the influence of instruction conditions on the evaluation of rhythmic repeated muscular endurance based on muscle oxygenation kinetics. Fifteen healthy young men performed repeated maximal rhythmic grips for 6 minutes under the following 3 instruction conditions: (1) "Squeeze as hard as you can during 2 seconds freely (Ex1)"; (2) "Squeeze as hard as you can quickly at the cue of a beep every 2 seconds (Ex2)"; and (3) "Squeeze as hard as you can quickly at the cue of a beep every 2 seconds, and then hold the exertion for 1 second (Ex3)". In the start phase of measurement during which larger exertion (above 80% maximal voluntary grip contraction) of grip strength is possible, the exertion values and muscle oxygenation kinetics were not significantly different among the 3 instruction conditions. However, a significant difference was found in muscle oxygenation kinetics after the middle phase (3 minutes) of measurement and also in the peak forces. Particularly, oxygen supply to the skeletal muscle as compared with oxygen consumption was greater in Ex2 than in Ex3. This study found that the evaluated muscle endurance differs considerably under various instruction conditions. The following instruction may be useful in the assessment of muscular endurance: "Squeeze as hard as you can quickly at the cue of a beep and then immediately relax". The present findings suggest that proper instructions are essential in various physical function tests and in the dynamometer handgrip test for occupational therapists and strength and conditioning professionals to obtain accurate measurements.

Moderate-Intensity Exercise Increases Subsequent Muscle Oxygenation and Speeds VO2 Kinetics in Chronic Heart Failure

Moderate-Intensity Exercise Increases Subsequent Muscle Oxygenation and Speeds VO2 Kinetics in Chronic Heart Failure

Comparisons of muscle oxygenation changes between arm and leg muscles during incremental rowing exercise with near-infrared spectroscopy

Our purpose is to compare the changes in muscle oxygenation in the vastus lateralis (VL) and biceps brachii (BB) muscles simultaneously using near-infrared spectroscopy (NIRS) during incremental rowing exercise in eight rowers. Based on the BB and VL muscle oxygenation patterns, two points are used to characterize the muscle oxygenation kinetics in both the arm and the leg muscles. The first point is the breaking point (Bp), which refers to an accelerated fall in muscle oxygenation that correlates with the gas exchange threshold (GET). The second point is the leveling-off point (Lo), which suggests the upper limit of O(2) extraction. The GET occurred at 63.3+/-2.4% of maximal oxygen uptake (VO(2 max)). The Bp appeared at 45.0+/-3.8% and 55.6+/-2.4% VO(2 max) in the BB and VL, respectively. The Lo appeared at 63.6+/-4.1% and 86.6+/-1.0% VO(2 max) in these two muscles, respectively. Both the Bp and the Lo occurred earlier in BB compared with VL. These results suggest that arm muscles have lower oxidative capacity than leg muscles during rowing exercise. The rowers with higher exercise performances showed heavier workloads, as evaluated by Bp and Lo. The monitoring of muscle oxygenation by NIRS in arm and leg muscles during rowing could be a useful guide for evaluation and training.

Effect of Intensive Interval Training during Unloading on Muscle Deoxygenation Kinetics

The present study investigated the effects of intensive interval training during 20-day of unloading on local muscle oxygenation kinetics evaluated by near infrared spectroscopy technique (NIRS). Eleven adult men completed 20-day unloading and were divided into two groups; the control (CON) group and training (TR) group. The TR group engaged in exercise training sessions that consisted of one-legged submaximal cycle exercise using the unloaded leg at 60 approximately 80% of VO(2peak) with intermittent rest periods, 25 min/day every other day. All subjects performed isometric knee extension exercise at 50% of their maximum voluntary contraction force before and after unloading. NIRS Delta[deoxy-Hb/Mb] signal was recorded from m. vastus lateralis and was fitted to an exponential equation in order to determine the kinetics parameters. The time constant (tau) of the % Delta[deoxy-Hb/Mb] was unchanged in the TR group, while it significantly increased in the CON group after unloading (pre, 5.0+/-1.0; post, 7.4+/-1.0 s). It is concluded that 20-day unloading increased the tau, suggesting deterioration of capacity for oxidative phosphorylation and oxygen utilization in a skeletal muscle. Additionally, the preservation of tau in the TR group suggested that intensive interval training could have an impact on the maintenance of muscle oxidative metabolism during unloading.

Point: The kinetics of oxygen uptake during muscular exercise do manifest time-delayed phases

Modeling a physiological system's response to a stressor, such as muscular exercise, demands more than a mathematically adequate characterization of its transient response profile: adequacy and appropriateness are not synonymous. The model constituents should be reflective of the system's

Relationships between Force and Muscle Oxygenation Kinetics during Sustained Static Gripping using a Progressive Workload

This study aimed to examine the relationships between force and subjective muscle-fatigue sensation (SMS), and muscle oxygenation kinetics during sustained static gripping using a progressive workload. Subjects consisted of 10 males (height 173.2+/-7.1 cm, body weight 70.3+/-15.1 kg, and age 21.1+/-1.5 years). They performed sustained static gripping with 7 gradually increasing relative demand values of 20% to 80% maximal voluntary contraction (MVC). The staging of the progressive workload was 10 s for 20% MVC, 20 s each for 30, 40, 50, 60, and 70% MVC, and 10 s for 80% MVC. Borg's SMS was used to measure the fatigue sensation of the antebrachial region in a pre-test and every 10 s during the test. The time to reach minimum Oxy-Hb/Mb appeared at about 50 s (52.6+/-25.2 s) after the onset of sustained static gripping, and the time to reach maximum Deoxy-Hb/Mb occurred later at 90 s. Significant and high correlations (r=0.632-0.721) were found between the time to reach maximum Deoxy-Hb/Mb, and Peak Force Time and Average Force. Even though the demand values caused a workload increase and reached 50% MVC, the change of Total Hb/Mb and Oxy-Hb/Mb kinetics was relatively small. Therefore, the effect caused by an obstruction of blood volume may not occur during the progressive workload. It was determined that the contraction time after the peak of SMS is relatively short and an individual difference in force value expands in the phase where SMS reaches its peak.

Cardiac denervation does/does not play a major role in exercise limitation after heart transplantation

Cardiac denervation does/does not play a major role in exercise limitation after heart transplantation

Relationships between Force-Time Parameters and Muscle Oxygenation Kinetics during Maximal Sustained Isometric Grip and Maximal Repeated Rhythmic Grip with Different Contraction Frequencies

The purposes of this study were to examine the relationships between various force-time parameters and muscle oxygenation kinetics during maximal sustained isometric grip (SIG) and maximal repeated rhythmic grips (RRG) with different grip intervals (interval times: 5, 4, 3, and 2 s). Subjects were 10 healthy young males, aged 20-26 years (height 173.9+/-7.3 cm, body mass 71.5+/-11.2 kg). After measuring maximal grip force, each subject performed the SIG and RRG tests with a target frequency of 12, 15, 20, and 30 grips.min(-1) (interval times: 5, 4, 3, and 2 s, respectively) for 6 min. The decreasing time until 80% MVC showed significant and high correlations with final force values in RRGs with over 3 s intervals (r=0.866-0.941), but not in the SIG and RRG with a 2 s interval. The time at the lowest Oxy-Hb/Mb value showed a significant and high correlation with the time at the highest Deoxy-Hb/Mb value only in the SIG and RRG with a 2 s interval (r=0.825-0.916). Oxy-Hb/Mb decreases markedly and deoxy-Hb/Mb increases after the onset of SIG due to the obstruction of blood flow caused by the increase in intramuscular pressure. A similar physiological response to that of SIG occurs also in RRG with a 2 s interval, but RRGs with intervals over 3 s achieve more resumption of blood flow in the muscular relaxation phase. Hence, in spite of the same RRGs, it was determined that RRGs with intervals over 3 s differ significantly in a changing pattern of grip force and muscle oxygen kinetics from RRGs with a 2 s interval.

Muscle oxygenation following concentric exercise

We investigated the hypothesis that a session of maximal concentric contraction exercise (CE) might impair muscle oxygenation and muscle blood flow. Ten healthy males performed a single bout of 70 maximal elbow flexion CE. Before and after CE on day 1 and over the next two days, maximum voluntary isometric torque (MVT), plasma creatine kinase activity (CK), serum myoglobin, elbow joint range of motion (ROM), subjects' perception of muscle soreness (SOR), and muscle oxygenation kinetics (using near infrared spectroscopy; NIRS) within biceps brachii were assessed. MVT and ROM decreased while SOR increased significantly after CE (p < 0.05), but recovered within the next day. There were not any significant changes in CK or myoglobin. Resting muscle oxygen saturation, oxyhaemoglobin and muscle oxygen uptake increased, and deoxyhaemoglobin decreased significantly after acute CE, and recovered by day 2. Although the changes in NIRS-derived variables were not significant in most conditions during isometric contractions of different intensities (i.e. 30%, 50% and 80% of MVT), there was a consistent pattern of change for those variables (i.e. decreasing immediately after CE, recovering on day 2 and increasing on day 3). Interestingly, the pattern of change in NIRS parameters mirrored CE-induced changes of MVT. In conclusion, concentric exercise did not produce prolonged changes in muscle oxygenation. The changes observed in NIRS-derived variables under resting condition may reflect an excess post exercise oxygen consumption.