Muscle oxidative capacity and work performance after training under local leg ischemia

1990 ◽  
Vol 69 (2) ◽  
pp. 785-787 ◽  
Author(s):  
L. Kaijser ◽  
C. J. Sundberg ◽  
O. Eiken ◽  
A. Nygren ◽  
M. Esbjornsson ◽  
...  
Keyword(s):  
Work Performance ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Training Session ◽  
Oxidative Capacity ◽  
Cycle Ergometer ◽  
Chamber Pressure ◽  
Exercise Tests ◽  
Rubber Membrane ◽  
The Difference

Healthy young men executed supine one-legged cycle training four times per week for 4 wk with legs and the cycle ergometer inside a pressure chamber, the opening of which was sealed by a rubber membrane at the level of the crotch. Each training session started by training one leg under ischemic conditions induced by increased chamber pressure (50 mmHg) at the highest intensity tolerable for 45 min. Then the other leg was trained with the same power profile but normal atmospheric chamber pressure. Before and after the training period, both legs executed one-legged exercise tests under both normal and increased chamber pressure and muscle biopsies were taken from the vastus lateralis. Ischemic training increased performance more than normal training, the difference being greater for exercise executed under ischemic conditions. The difference in performance increase between the legs was paralleled by a greater muscle citrate synthase activity in the ischemically than in the normally trained leg.

Longitudinal changes in the kinetic response to heavy-intensity exercise in children

2004 ◽  
Vol 97 (2) ◽  
pp. 460-466 ◽  
Author(s):  
Samantha G. Fawkner ◽  
Neil Armstrong
Keyword(s):  
Slow Component ◽  
Phase 1 ◽  
Exponential Model ◽  
Cycle Ergometer ◽  
Primary Component ◽  
Total Change ◽  
Exercise Tests ◽  
Longitudinal Changes ◽  
Dependent Change ◽  
The Difference

The purpose of this study was to investigate longitudinal changes with age in the kinetic response to cycling at heavy-intensity exercise in boys and girls. Twenty-two prepubertal children (13 male, 9 female) carried out a series of exercise tests on two test occasions with a 2-yr interval. On each test occasion, the subject completed multiple transitions from baseline to 40% of the difference between their previously determined V-slope and peak O2 uptake (V̇o2) for 9 min on an electronically braked cycle ergometer. Each subject's breath-by-breath responses were interpolated to 1-s intervals, time aligned, and averaged. The data after phase 1 were fit with 1) a double exponential model and 2) a single exponential model within a fitting window that was previously identified to exclude the slow component. There were no significant differences in the parameters of the primary component between each model. Subsequent analysis was carried out using model 2. The V̇o2 slow component was computed as the difference between the amplitude of the primary component and the end-exercise V̇o2 and was expressed as the percent contribution to the total change in V̇o2. Over the 2-yr period, the primary time constant (boys 16.8 ± 5.3 and 21.7 ± 5.3 s, girls 21.1 ± 8.1 and 26.4 ± 8.4 s, first and second occasion, respectively) and the relative amplitude of the slow component (boys 9.4 ± 4.6 and 13.8 ± 5.3%, girls 10.3 ± 2.4 and 15.5 ± 2.8%, first and second occasion, respectively) significantly increased with no sex differences. The data demonstrate that children do display a slow-component response to exercise and are consistent with an age-dependent change in the muscles' potential for O2 utilization.

Plasma glucose kinetics during exercise in subjects with high and low lactate thresholds

1992 ◽  
Vol 73 (5) ◽  
pp. 1873-1880 ◽  
Author(s):  
A. R. Coggan ◽  
W. M. Kohrt ◽  
R. J. Spina ◽  
J. P. Kirwan ◽  
D. M. Bier ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Plasma Glucose ◽  
Glucose Oxidation ◽  
Citrate Synthase ◽  
Metabolic Response ◽  
Vastus Lateralis ◽  
Cycle Ergometer ◽  
Vastus Lateralis Muscle ◽  
Respiratory Capacity ◽  
Group A

The purpose of this study was to test the hypothesis that the rate of plasma glucose oxidation during exercise is inversely related to muscle respiratory capacity. To this end, 14 subjects were studied: in 7 of these subjects, the blood lactate threshold (LT) occurred at a relatively high intensity [i.e., at 65 +/- 2% of peak cycle ergometer oxygen uptake (VO2 peak)], whereas in the other 7 subjects, LT occurred at a relatively low intensity (i.e., at 45 +/- 2% of VO2 peak). VO2peak did not differ between the two groups, but citrate synthase activity in the vastus lateralis muscle was 53% higher (P < 0.05) in the high LT group. A primed continuous infusion of [U-13C]glucose was used to quantify rates of glucose appearance (Ra), disappearance (Rd), and oxidation (R(ox)) during 90 min of exercise at 55% VO2peak. Although both absolute and relative rates of oxygen uptake during exercise were similar in the two groups, mean Ra and Rd were 17% lower (P < 0.001) in the high LT group, and mean R(ox) was 25% lower (21.0 +/- 2.6 vs. 27.9 +/- 2.6 mumol.min-1.kg-1; P < 0.001). The percentage of total energy derived from glucose oxidation was inversely related to muscle citrate synthase activity (r = -0.85; P < 0.01). These data support the concept that skeletal muscle respiratory capacity has a major role in determining the metabolic response to submaximal exercise.

Pulmonary emphysema decreases hamster skeletal muscle oxidative enzyme capacity

1998 ◽  
Vol 85 (1) ◽  
pp. 210-214 ◽  
Author(s):  
John P. Mattson ◽  
David C. Poole
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Intratracheal Instillation ◽  
Oxidative Capacity ◽  
Activity Level ◽  
Oxidative Enzyme ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Reduced Physical Activity

Skeletal muscle oxidative enzyme capacity is impaired in patients suffering from emphysema and chronic obstructive pulmonary disease. This effect may result as a consequence of the physiological derangements because of the emphysema condition or, alternatively, as a consequence of the reduced physical activity level in these patients. To explore this issue, citrate synthase (CS) activity was measured in selected hindlimb muscles and the diaphragm of Syrian Golden hamsters 6 mo after intratracheal instillation of either saline (Con, n = 7) or elastase [emphysema (Emp); 25 units/100 g body weight, n = 8]. Activity level was monitored, and no difference between groups was found. Excised lung volume increased with emphysema (Con, 1.5 ± 0.3 g; Emp, 3.0 ± 0.3 g, P < 0.002). Emphysema significantly reduced CS activity in the gastrocnemius (Con, 45.1 ± 2.0; Emp, 39.2 ± 0.8 μmol ⋅ min−1 ⋅ g wet wt−1, P < 0.05) and vastus lateralis (Con, 48.5 ± 1.5; Emp, 44.9 ± 0.8 μmol ⋅ min−1 ⋅ g wet wt−1, P < 0.05) but not in the plantaris (Con, 47.4 ± 3.9; Emp, 48.0 ± 2.1 μmol ⋅ min−1 ⋅ g wet wt−1, P < 0.05) muscle. In contrast, CS activity increased in the costal (Con, 61.1 ± 1.8; Emp, 65.1 ± 1.5 μmol ⋅ min−1 ⋅ g wet wt−1, P < 0.05) and crural (Con, 58.5 ± 2.0; Emp, 65.7 ± 2.2 μmol ⋅ min−1 ⋅ g wet wt−1, P < 0.05) regions of the diaphragm. These data indicate that emphysema per se can induce decrements in the oxidative capacity of certain nonventilatory skeletal muscles that may contribute to exercise limitations in the emphysematous patient.

scholarly journals Relationships between maximal muscle oxidative capacity and blood lactate removal after supramaximal exercise and fatigue indexes in humans

2004 ◽  
Vol 97 (6) ◽  
pp. 2132-2138 ◽  
Author(s):  
C. Thomas ◽  
P. Sirvent ◽  
S. Perrey ◽  
E. Raynaud ◽  
J. Mercier
Keyword(s):  
Blood Lactate ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Oxidative Capacity ◽  
Slow Phase ◽  
Vastus Lateralis Muscle ◽  
Supramaximal Exercise ◽  
Muscle Oxidative Capacity ◽  
S Cycling ◽  
Lactate Removal

The present study investigated whether blood lactate removal after supramaximal exercise and fatigue indexes measured during continuous and intermittent supramaximal exercises are related to the maximal muscle oxidative capacity in humans with different training status. Lactate recovery curves were obtained after a 1-min all-out exercise. A biexponential time function was then used to determine the velocity constant of the slow phase (γ2), which denoted the blood lactate removal ability. Fatigue indexes were calculated during all-out (FIAO) and repeated 10-s cycling sprints (FISprint). Biopsies were taken from the vastus lateralis muscle, and maximal ADP-stimulated mitochondrial respiration ( Vmax) was evaluated in an oxygraph cell on saponin-permeabilized muscle fibers with pyruvate + malate and glutamate + malate as substrates. Significant relationships were found between γ2 and pyruvate + malate Vmax ( r = 0.60, P < 0.05), γ2 and glutamate + malate Vmax ( r = 0.66, P < 0.01), and γ2 and citrate synthase activity ( r = 0.76, P < 0.01). In addition, γ2, glutamate + malate Vmax, and pyruvate + malate Vmax were related to FIAO (γ2 − FIAO: r = 0.85; P < 0.01; glutamate + malate Vmax − FIAO: r = 0.70, P < 0.01; and pyruvate + malate Vmax − FIAO: r = 0.63, P < 0.01) and FISprint (γ2 − FISprint: r = 0.74, P < 0.01; glutamate + malate Vmax − FISprint: r = 0.64, P < 0.01; and pyruvate + malate Vmax − FISprint: r = 0.46, P < 0.01). In conclusion, these results suggested that the maximal muscle oxidative capacity was related to blood lactate removal ability after a 1-min all-out test. Moreover, maximal muscle oxidative capacity and blood lactate removal ability were associated with the delay in the fatigue observed during continuous and intermittent supramaximal exercises in well-trained subjects.

Training cessation does not alter GLUT-4 protein levels in human skeletal muscle

1993 ◽  
Vol 74 (2) ◽  
pp. 776-781 ◽  
Author(s):  
J. A. Houmard ◽  
T. Hortobagyi ◽  
P. D. Neufer ◽  
R. A. Johns ◽  
D. D. Fraser ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Oxidative Capacity ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Protein Levels ◽  
Glut 4 ◽  
Before And After ◽  
Oriented Activity

The purpose of this study was to determine whether short-term training cessation resulted in reduced GLUT-4 protein levels. Endurance- (n = 12, ET) and strength-trained (n = 12) individuals (ST) were examined before and after 14 days of training withdrawal. GLUT-4 content was determined from muscle biopsy samples of the gastrocnemius in ET and the vastus lateralis in ST. Insulin sensitivity (oral glucose tolerance test) was significantly (P < 0.05) reduced in ET and ST with training cessation. GLUT-4 content was unaltered (P > 0.05) in both groups (92 and 100% of trained values for ET and ST, respectively). In ET, citrate synthase activity decreased significantly (P < 0.05) with training withdrawal (41.0 +/- 3.6 vs. 30.6 +/- 2.8 mumol.g-1.min-1); in ST no change was evident. The decrement in insulin sensitivity with the cessation of endurance- or resistance-oriented activity is therefore not associated with a reduction in GLUT-4 protein content. Muscle oxidative capacity and GLUT-4 content do not coincide with the removal of endurance training.

CK and LD isozymes in human single muscle fibers in trained athletes

1989 ◽  
Vol 66 (6) ◽  
pp. 2717-2720 ◽  
Author(s):  
F. S. Apple ◽  
P. A. Tesch
Keyword(s):  
Citrate Synthase ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Oxidative Capacity ◽  
Metabolic Adaptation ◽  
Fiber Types ◽  
Trained Group ◽  
Energy Demands ◽  
The Individual

Individual human muscle fibers from the vastus lateralis were isolated from age-matched endurance-trained and strength-trained athletes and untrained controls. Slow- (ST) and fast-twitch (FT) fibers were assayed for total creatine kinase (CK), CK-MB, total lactate dehydrogenase (LD), the LD isozyme that predominates in the heart muscle of most vertebrates (LD1), and citrate synthase (CS). Regardless of training of the athletes, both CK-MB and CS were higher in ST than in FT fibers. Also, irrespective of fiber type, CK-MB and CS were greatest in the endurance-trained group. A positive correlation existed between CK-MB and CS, relating oxidative capacity of individual fibers with CK-MB. Total CK varied little among the fiber types, trained groups, or controls. Total LD in FT fibers was greater than in ST fibers in all groups, with only ST fibers from the endurance-trained group containing substantial amounts of LD1. These findings suggest that specific training, endurance exercise, causes a favorable metabolic adaptation of CK and LD isozymes at the individual fiber level, allowing for the muscle to cope with increased energy demands during prolonged exercise.

scholarly journals Muscle oxygenation maintained during repeated sprints despite inspiratory muscle loading

2019 ◽  
Author(s):  
Ramón F. Rodriguez ◽  
Nathan E. Townsend ◽  
Robert J. Aughey ◽  
François Billaut
Keyword(s):  
Near Infrared ◽  
Vastus Lateralis ◽  
Saturation Index ◽  
Work Of Breathing ◽  
Cycle Ergometer ◽  
Experimental Session ◽  
Meaningful Difference ◽  
Sprint Exercise ◽  
Sixth Intercostal Space ◽  
The Difference

AbstractA high work of breathing can compromise limb oxygen delivery during sustained high-intensity exercise. However, it is unclear if the same is true for intermittent sprint exercise. This project examined the addition of an inspiratory load on locomotor muscle tissue reoxygenation during repeated-sprint exercise. Ten healthy males completed three experimental sessions of ten 10 s sprints, separated by 30 s of passive rest on a cycle ergometer. The first two sessions were “all-out’ efforts performed without (CTRL) or with inspiratory loading (INSP) in a randomised and counterbalanced order. The third experimental session (MATCH) consisted of ten 10 s work-matched intervals. Tissue saturation index (TSI) and deoxy-haemoglobin (HHb) of the vastus lateralis and sixth intercostal space was monitored with near-infrared spectroscopy. Vastus lateralis reoxygenation (ΔReoxy) was calculated as the difference from peak HHb (sprint) to nadir HHb (recovery). Total mechanical work completed was similar between INSP and CTRL (effect size: −0.18, 90% confidence limit ±0.43), and differences in vastus lateralis TSI during the sprint (−0.01, ±0.33) and recovery (−0.08, ±0.50) phases were unclear. There was also no meaningful difference in ΔReoxy (0.21, ±0.37). Intercostal HHb was higher in the INSP session compared to CTRL (0.42, ±0.34), whilst the difference was unclear for TSI (−0.01, ±0.33). During MATCH exercise, differences in vastus lateralis TSI were unclear compared to INSP for both sprint (0.10, ±0.30) and recovery (−0.09, ±0.48) phases, and there was no meaningful difference in ΔReoxy (−0.25, ±0.55). Intercostal TSI was higher during MATCH compared to INSP (0.95, ±0.53), whereas HHb was lower (−1.09, ±0.33). The lack of difference in ΔReoxy between INSP and CTRL suggests that for intermittent sprint exercise, the metabolic O2demands of both the respiratory and locomotor muscles can be met. Additionally, the similarity of the MATCH suggests that ΔReoxy was maximal in all exercise conditions.

scholarly journals Sodium bicarbonate ingestion prior to training improves mitochondrial adaptations in rats

2010 ◽  
Vol 299 (2) ◽  
pp. E225-E233 ◽  
Author(s):  
David J. Bishop ◽  
Claire Thomas ◽  
Tom Moore-Morris ◽  
Michail Tonkonogi ◽  
Kent Sahlin ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
Citrate Synthase ◽  
Training Session ◽  
Oxidative Capacity ◽  
Ion Accumulation ◽  
Hydrogen Ion ◽  
Time To Exhaustion ◽  
Mitochondrial Mass ◽  
Palmitoyl Carnitine ◽  
Male Wistar Rats

We tested the hypothesis that reducing hydrogen ion accumulation during training would result in greater improvements in muscle oxidative capacity and time to exhaustion (TTE). Male Wistar rats were randomly assigned to one of three groups (CON, PLA, and BIC). CON served as a sedentary control, whereas PLA ingested water and BIC ingested sodium bicarbonate 30 min prior to every training session. Training consisted of seven to twelve 2-min intervals performed five times/wk for 5 wk. Following training, TTE was significantly greater in BIC (81.2 ± 24.7 min) compared with PLA (53.5 ± 30.4 min), and TTE for both groups was greater than CON (6.5 ± 2.5 min). Fiber respiration was determined in the soleus (SOL) and extensor digitorum longus (EDL), with either pyruvate (Pyr) or palmitoyl carnitine (PC) as substrates. Compared with CON (14.3 ± 2.6 nmol O2·min−1·mg dry wt−1), there was a significantly greater SOL-Pyr state 3 respiration in both PLA (19.6 ± 3.0 nmol O2·min−1·mg dry wt−1) and BIC (24.4 ± 2.8 nmol O2·min−1·mg dry wt−1), with a significantly greater value in BIC. However, state 3 respiration was significantly lower in the EDL from both trained groups compared with CON. These differences remained significant in the SOL, but not the EDL, when respiration was corrected for citrate synthase activity (an indicator of mitochondrial mass). These novel findings suggest that reducing muscle hydrogen ion accumulation during running training is associated with greater improvements in both mitochondrial mass and mitochondrial respiration in the soleus.

Weight loss-induced rise in plasma pollutant is associated with reduced skeletal muscle oxidative capacity

2002 ◽  
Vol 282 (3) ◽  
pp. E574-E579 ◽  
Author(s):  
Pascal Imbeault ◽  
Angelo Tremblay ◽  
Jean-Aimé Simoneau ◽  
Denis R. Joanisse
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Oxidative Metabolism ◽  
Polychlorinated Biphenyl ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Oxidative Capacity ◽  
Response To Treatment ◽  
Similar Reduction ◽  
Muscle Enzyme

In this study, we examined whether weight loss-induced changes in plasma organochlorine compounds (OC) were associated with those in skeletal muscle markers of glycolytic and oxidative metabolism. Vastus lateralis skeletal muscle enzyme activities and plasma OC (Aroclor 1260, polychlorinated biphenyl 153, p,p′-DDE, β-hexachlorocyclohexane, and hexachlorobenzene) were measured before and after a weight loss program in 17 men and 20 women. Both sexes showed a similar reduction in body weight (∼11 kg) in response to treatment, although men lost significantly more fat mass than women ( P < 0.05). Enzymatic markers of glycolysis, phosphofructokinase (PFK) activity, and oxidative metabolism, β-hydroxyacyl-CoA dehydrogenase (HADH), citrate synthase (CS), and cytochrome c oxidase (COX) activities, remained unchanged after weight loss. A significant increase in plasma OC levels was observed in response to weight loss, an effect that was more pronounced in men. No relationship was observed between changes in OC and those in PFK activity in either sex [−0.31 < r < 0.12, not significant (NS)]. However, the greater the increase in plasma OC levels, the greater the reduction in oxidative enzyme (HADH, CS, COX) activities was in response to weight loss in men (−0.75 < r < −0.50, P < 0.05) but not in women (−0.33 < r < 0.33, NS). These results suggest that the weight loss-induced increase in plasma pollutant levels is likely to be associated with reduced skeletal muscle oxidative metabolism in men but not in women.

Effect of detraining on GLUT-4 protein in human skeletal muscle

1994 ◽  
Vol 77 (3) ◽  
pp. 1532-1536 ◽  
Author(s):  
M. McCoy ◽  
J. Proietto ◽  
M. Hargreves
Keyword(s):  
Protein Content ◽  
Glucose Tolerance Test ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Insulin Response ◽  
Oxidative Capacity ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Protein Levels ◽  
Glut 4

The present study was undertaken to examine the effect of 10 days of detraining levels of GLUT-4 protein expression and citrate synthase (CS) activity in the vastus lateralis of trained men. During the course of normal training, seven endurance-trained (T) men and eight age- and weight-matched active but untrained (UT) men underwent an oral glucose tolerance test (OGTT) after an overnight fast. Muscle samples were obtained from the vastus lateralis by needle biopsy for measurement of GLUT-4 protein and CS activity. The tests were repeated on six of the T subjects after 10 days of detraining (DT men). The area under the insulin response curve during OGTT was lower in T men than in DT and UT men (22.4 +/- 2.8, 32.1 +/- 5.9, and 39.9 +/- 4.7 x 10(-3) pmol.l-1.min-1, respectively; P < 0.05). There were no differences between groups in the glucose responses to OGTT. GLUT-4 protein levels and CS activity were higher in T men than in DT and UT men (GLUT-4: 4.37 +/- 0.40, 2.92 +/- 0.53, and 1.71 +/- 0.22 arbitrary standard units and CS: 47.12 +/- 4.75, 33.63 +/- 3.98, and 24.51 +/- 2.97 mumol.min-1.g-1, respectively; both P < 0.05). Muscle GLUT-4 protein content was correlated with CS activity in all three groups (r = 0.64, 0.68, and 0.96 for UT, T, and DT men, respectively). These results suggest that muscle GLUT-4 protein content and oxidative capacity undergo parallel adaptations after detraining in previously well-trained men.

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