Early muscular and metabolic adaptations to prolonged exercise training in humans

1991 ◽  
Vol 70 (5) ◽  
pp. 2032-2038 ◽  
Author(s):  
H. J. Green ◽  
S. Jones ◽  
M. E. Ball-Burnett ◽  
D. Smith ◽  
J. Livesey ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Creatine Phosphate ◽  
Area Ratio ◽  
Vastus Lateralis Muscle ◽  
Metabolic Potential ◽  
Oxidative Potential ◽  
Fiber Area ◽  
Glycerophosphate Dehydrogenase

A short-term training program involving 2 h of daily exercise at 59% of peak O2 uptake (VO2max) repeated for 10-12 consecutive days was employed to determine the significance of adaptations in energy metabolic potential on alterations in energy metabolism and substrate utilization in working muscle. The initial VO2max determined before training on the eight male subjects was 53.0 +/- 2.0 (SE) ml.kg-1.min-1. Analysis of samples obtained by needle biopsy from the vastus lateralis muscle before exercise (0 min) and at 15, 60, and 99 min of exercise indicated that on the average training resulted (P less than 0.05) in a 6.5% higher concentration of creatine phosphate, a 9.9% lower concentration of creatine, and a 39% lower concentration of lactate. Training had no effect on ATP concentration. These adaptations were also accompanied by a reduction in the utilization in glycogen such that by the end of exercise glycogen concentration was 47.1% higher in the trained muscle. Analysis of the maximal activities of representative enzymes of different metabolic pathways and segments indicated no change in potential in the citric acid cycle (succinate dehydrogenase, citrate synthase), beta-oxidation (3-hydroxyacyl CoA dehydrogenase), glucose phosphorylation (hexokinase), or potential for glycogenolysis (phosphorylase) and glycolysis (pyruvate kinase, phosphofructokinase, alpha-glycerophosphate dehydrogenase, lactate dehydrogenase). With the exception of increases in the capillary-to-fiber area ratio in type IIa fibers, no change was found in any fiber type (types I, IIa, and IIb) for area, number of capillaries, capillary-to-fiber area ratio, or oxidative potential with training.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Downregulation in muscle Na+-K+-ATPase following a 21-day expedition to 6,194 m

2000 ◽  
Vol 88 (2) ◽  
pp. 634-640 ◽  
Author(s):  
Howard Green ◽  
Brian Roy ◽  
Susan Grant ◽  
Margaret Burnett ◽  
Russ Tupling ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Succinic Dehydrogenase ◽  
Vastus Lateralis Muscle ◽  
Mitochondrial Enzymes ◽  
Succinic Dehydrogenase Activity ◽  
Oxidative Potential ◽  
Tissue Samples ◽  
Fiber Type Distribution

To investigate the hypothesis that acclimatization to altitude would result in a downregulation in muscle Na+-K+-ATPase pump concentration, tissue samples were obtained from the vastus lateralis muscle of six volunteers (5 males and 1 female), ranging in age from 24 to 35 yr, both before and within 3 days after a 21-day expedition to the summit of Mount Denali, Alaska (6,194 m). Na+-K+-ATPase, measured by the [3H]ouabain-binding technique, decreased by 13.8% [348 ± 12 vs. 300 ± 7.6 (SE) pmol/g wet wt; P< 0.05]. No changes were found in the maximal activities (mol ⋅ kg protein− 1 ⋅ h− 1) of the mitochondrial enzymes, succinic dehydrogenase (3.63 ± 0.20 vs. 3.25 ± 0.23), citrate synthase (4.76 ± 0.44 vs. 4.94 ± 0.44), and malate dehydrogenase (12.6 ± 1.8 vs. 12.7 ± 1.2). Similarly, the expedition had no effect on any of the histochemical properties examined, namely fiber-type distribution (types I, IIA, IIB, IC, IIC, IIAB), area, capillarization, and succinic dehydrogenase activity. Peak aerobic power (52.3 ± 2.1 vs. 50.6 ± 1.9 ml ⋅ kg− 1 ⋅ min− 1) and body mass (76.9 ± 3.7 vs. 75.5 ± 2.9 kg) were also unaffected. We concluded that acclimatization to altitude results in a downregulation in muscle Na+-K+-ATPase pump concentration, which occurs without changes in oxidative potential and other fiber-type histochemical properties.

Enzyme activities of FT and ST muscle fibers in heavy-resistance trained athletes

1989 ◽  
Vol 67 (1) ◽  
pp. 83-87 ◽  
Author(s):  
P. A. Tesch ◽  
A. Thorsson ◽  
B. Essen-Gustavsson
Keyword(s):  
Resistance Training ◽  
Enzyme Activities ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Fiber Types ◽  
Tissue Samples ◽  
Fiber Area ◽  
Freeze Dried

Tissue samples were obtained from the vastus lateralis muscle of elite olympic weight and power lifters (OL/PL, n = 6), bodybuilders (BB, n = 7), and sedentary men (n = 7). Enzyme activities of citrate synthase (CS), lactate dehydrogenase (LD), 3-OH-acyl-CoA-dehydrogenase (HAD), and myokinase (MK) were assayed on freeze-dried dissected pools of slow-twitch (ST) and fast-twitch (FT) fiber fragments by fluorometric means. Histochemical analyses were carried out to assess fiber type composition and fiber area. CS and HAD activities were lower (P less than 0.05), and LD and MK were higher (P less than 0.05) in FT than ST fibers in the entire subject pool (n = 20). CS of FT fibers and HAD of ST fibers were lower in athletes (P less than 0.05–0.01) compared with nonathletes, whereas LD of both fiber types was higher (P less than 0.05–0.001) in athletes. CS activity of ST fibers and MK activity of FT fibers were higher (P less than 0.05) in BB compared with OL/PL. FT and ST fiber area was greater (P less than 0.05) in athletes than in nonathletes. BB displayed greater (P less than 0.05) fiber size than OL/PL. FT/ST area was greater (P less than 0.05) in OL/PL than BB. It is suggested that long-term heavy-resistance training results in specific metabolic adaptations of FT and ST fiber types. These changes appear to be influenced by the type of resistance training.

Decreased glucose turnover after short-term training is unaccompanied by changes in muscle oxidative potential

1995 ◽  
Vol 269 (2) ◽  
pp. E222-E230 ◽  
Author(s):  
S. M. Phillips ◽  
H. J. Green ◽  
M. A. Tarnopolsky ◽  
S. M. Grant
Keyword(s):  
Blood Glucose ◽  
Citrate Synthase ◽  
Blood Glucose Concentration ◽  
Vastus Lateralis ◽  
Glucose Turnover ◽  
Vastus Lateralis Muscle ◽  
Metabolic Clearance ◽  
Glycogen Depletion ◽  
Oxidative Potential ◽  
Mitochondrial Potential

This study investigated the hypothesis that training-induced reductions in exercise blood glucose utilization can occur independently of increases in muscle mitochondrial potential. To induce a training adaptation, eight active participants (23 +/- 1 yr, 80.6 +/- 3.7 kg, mean +/- SE) with a maximal oxygen consumption (VO2max) of 45.5 +/- 2.4 ml.kg-1.min-1, cycled at 59% VO2max for 2 h per day for 10 consecutive days. Measurements of blood glucose appearance (Ra) and disappearance (Rd), using a primed continuous infusion of [6,6-2H2]glucose, were made during 90 min of cycle exercise (59% VO2max) performance before and after training. Training resulted in a 25% decrease (P < 0.01) in mean glucose Ra during exercise (43.0 +/- 3.7 to 34.4 +/- 2.8 mumol.kg-1.min-1). Since blood glucose concentration was not different between training conditions, glucose metabolic clearance rate was also depressed (P < 0.05). Exercise-induced glycogen depletion in vastus lateralis muscle was reduced (P < 0.05) with training. Calculation of carbohydrate and fat oxidation based on the respiratory exchange ratio supported a shift toward greater preference for fat. Because training did not elicit changes in the maximal activities of citrate synthase and malate dehydrogenase, two enzymes of the citric acid cycle, it would appear that increases in mitochondrial potential are not necessary for the adaptations that occurred.

Sequential increases in capillarization and mitochondrial enzymes in low-frequency-stimulated rabbit muscle

1998 ◽  
Vol 274 (3) ◽  
pp. C810-C818 ◽  
Author(s):  
Dejan Škorjanc ◽  
Frank Jaschinski ◽  
Georg Heine ◽  
Dirk Pette
Keyword(s):  
Citrate Synthase ◽  
Contractile Activity ◽  
Fiber Type ◽  
Low Frequency ◽  
Mitochondrial Enzymes ◽  
Rabbit Muscle ◽  
Mrna Levels ◽  
Metabolic Potential ◽  
Oxidative Potential ◽  
Time Pattern

To investigate temporal changes in capillarization and increases in mitochondrial enzyme activity, rabbit tibialis anterior muscles underwent chronic low-frequency stimulation for up to 50 days. Capillary density (CD), capillary-to-fiber ratio (C/F), intercapillary distance (ICD), and mean capillary area (MCA), as well as several other parameters of capillarization, were examined. In addition, tissue levels of mRNA specific to vascular endothelial growth factor (VEGF) were assessed by reverse transcriptase-polymerase chain reaction. Citrate synthase (CS) activity, a marker of aerobic-oxidative metabolic potential, was measured in the same muscles. Significant increases in CD and C/F, respectively, and decreases in ICD and MCA were observed after 2 days. These changes reached stable maxima by 14 days. The increases in capillarization occurred in a fiber-type-specific manner, affecting type IId fibers before types IIda and IIa. VEGF mRNA levels increased in a bimodal time pattern with a first elevation (2.5-fold) after 1 day and a second (9-fold) after 6–8 days. Increases in CS were first noted after 8 days. Obviously, increases in capillarization as induced by enhanced contractile activity precede increases in the aerobic-oxidative potential of energy metabolism.

Adaptations in skeletal muscle exercise metabolism to a sustained session of heavy intermittent exercise

2000 ◽  
Vol 278 (1) ◽  
pp. E118-E126 ◽  
Author(s):  
H. Green ◽  
R. Tupling ◽  
B. Roy ◽  
D. O'Toole ◽  
M. Burnett ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Intermittent Exercise ◽  
Vastus Lateralis ◽  
Maximal Oxygen Consumption ◽  
Training Session ◽  
Creatine Phosphate ◽  
Oxidative Potential ◽  
Similar Time ◽  
Muscle Lactate ◽  
Metabolic Adaptations

The purpose of this study was to investigate the hypothesis that a single, extended session of heavy exercise would be effective in inducing adaptations in energy metabolism during exercise in the absence of increases in oxidative potential. Ten healthy males [maximal aerobic power (V˙o 2 peak) = 43.4 ± 2.2 (SE) ml ⋅ kg−1 ⋅ min−1] participated in a 16-h training session involving cycling for 6 min each hour at ∼90% of maximal oxygen consumption. Measurements of metabolic changes were made on tissue extracted from the vastus lateralis during a two-stage standardized submaximal cycle protocol before (Pre) and 36–48 h after (Post) the training session. At Pre, creatine phosphate (PCr) declined ( P < 0.05) by 32% from 0 to 3 min and then remained stable until 20 min of exercise at 60%V˙o 2 peak before declining ( P < 0.05) by a further 35% during 20 min of exercise at 75%V˙o 2 peak. Muscle lactate (mmol/kg dry wt) progressively increased ( P < 0.05) from 4.59 ± 0.64 at 0 min to 17.8 ± 2.7 and 30.9 ± 5.3 at 3 and 40 min, respectively, whereas muscle glycogen (mmol glucosyl units/kg dry wt) declined ( P < 0.05) from a rest value of 360 ± 24 to 276 ± 31 and 178 ± 36 at similar time points. During exercise after the training session, PCr and glycogen were not as depressed ( P < 0.05), and increases in muscle lactate were blunted ( P < 0.05). All of these changes occurred in the absence of increases in oxidative potential as measured by the maximal activities of citrate synthase and malate dehydrogenase. These findings are consistent with other studies, namely, that muscle metabolic adaptations to regular exercise are an early adaptive event that occurs before increases in oxidative potential.

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.

In vitro human masseter muscle hypersensitivity: a possible explanation for increase in masseter tone

1996 ◽  
Vol 80 (5) ◽  
pp. 1547-1553 ◽  
Author(s):  
P. J. Adnet ◽  
H. Reyford ◽  
B. M. Tavernier ◽  
T. Etchrivi ◽  
I. Krivosic ◽  
...  
Keyword(s):  
Masseter Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Threshold Concentration ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Cross Sectional ◽  
Significant Difference ◽  
Maximal Tension

To determine whether a difference in fiber-type caffeine and Ca2+ sensitivities exists between human masseter and vastus lateralis skeletal muscle, we compared the fiber-type caffeine sensitivities in chemically skinned muscle fibers from 13 masseter and 18 vastus lateralis muscles. Caffeine sensitivity was defined as the threshold concentration inducing > 10% of the maximal tension obtained after the fiber was loaded with a 1.6 x 10(-2) mM Ca2+ solution for 30 s. Significant difference in the mean caffeine sensitivity was found between type I masseter fibers [2.57 +/- 1.32 (SD) mM] vs. type I (6.02 +/- 1.74 mM) and type II vastus lateralis fibers (11.25 +/- 3.13 mM). Maximal Ca(2+)-activated force per cross-sectional area was significantly different between masseter and vastus lateralis fibers. However, the Ca2+ concentration corresponding to half-maximal tension (pCa50) was not significantly different between type I masseter (pCa50 5.9 +/- 0.02) and type I vastus lateralis muscle (pCa50 6.01 +/- 0.08). These results suggest that the increase in caffeine sensitivity of masseter muscle reflects the presence of a low reactivity threshold of the sarcoplasmic reticulum.

Regulation of fiber size, oxidative potential, and capillarization in human muscle by resistance exercise

1999 ◽  
Vol 276 (2) ◽  
pp. R591-R596 ◽  
Author(s):  
H. Green ◽  
C. Goreham ◽  
J. Ouyang ◽  
M. Ball-Burnett ◽  
D. Ranney
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Succinic Dehydrogenase ◽  
Quadriceps Muscle ◽  
Cellular Tissue ◽  
Cross Sectional Area ◽  
Fiber Types ◽  
Sectional Area ◽  
Oxidative Potential ◽  
Cross Sectional

To examine the hypothesis that increases in fiber cross-sectional area mediated by high-resistance training (HRT) would result in a decrease in fiber capillarization and oxidative potential, regardless of fiber type, we studied six untrained males (maximum oxygen consumption, 45.6 ± 2.3 ml ⋅ kg−1 ⋅ min−1; mean ± SE) participating in a 12-wk program designed to produce a progressive hypertrophy of the quadriceps muscle. The training sessions, which were conducted 3 times/wk, consisted of three sets of three exercises, each performed for 6–8 repetitions maximum (RM). Measurements of fiber-type distribution obtained from tissue extracted from the vastus lateralis at 0, 4, 7, and 12 wk indicated reductions ( P < 0.05) in type IIB fibers (15.1 ± 2.1% vs. 7.2 ± 1.3%) by 4 wk in the absence of changes in the other fiber types (types I, IIA, and IIAB). Training culminated in a 17% increase ( P < 0.05) in cross-sectional area by 12 wk with initial increases observed at 4 wk. The increase was independent of fiber type-specific changes. The number of capillaries in contact with each fiber type increased by 12 wk, whereas capillary contacts-to-fiber area ratios remained unchanged. In a defined cross-sectional field, HRT also increased the capillaries per fiber at 12 wk. Training failed to alter cellular oxidative potential, as measured by succinic dehydrogenase (SDH) activity, regardless of fiber type and training duration. It is concluded that modest hypertrophy induced by HRT does not compromise cellular tissue capillarization and oxidative potential regardless of fiber type.

Muscle blood flow during exercise in sedentary and trained hypothyroid rats

1995 ◽  
Vol 269 (6) ◽  
pp. H1949-H1954 ◽  
Author(s):  
R. M. McAllister ◽  
M. D. Delp ◽  
K. A. Thayer ◽  
M. H. Laughlin
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Muscle Blood Flow ◽  
Treadmill Running ◽  
Exercise Intolerance ◽  
Vastus Lateralis Muscle ◽  
Blood Flows ◽  
Vastus Intermedius

Hypothyroidism is characterized by exercise intolerance. We hypothesized that active muscle blood flow during in vivo exercise is inadequate in the hypothyroid state. Additionally, we hypothesized that endurance exercise training would restore normal blood flow during acute exercise. To test these hypotheses, rats were made hypothyroid (Hypo) over 3-4 mo with propylthiouracil. A subset of Hypo rats was trained (THypo) on a treadmill at 30 m/min (15% grade) for 60 min/day 5 days/wk over 10-15 wk. Hypothyroidism was evidenced by approximately 80% reductions in plasma triiodothyronine levels in Hypo and THypo and by 40-50% reductions in citrate synthase activities in high oxidative muscles in Hypo compared with euthyroid (Eut) rats. Training efficacy was indicated by increased (25-100%) citrate synthase activities in muscles of THypo vs. Hypo. Regional blood flows were determined by the radiolabeled microsphere method before exercise and at 1-2 min of treadmill running at 15 m/min (0% grade). Preexercise muscle blood flows were generally similar among groups. During exercise, however, flows were lower in Hypo than in Eut for high oxidative muscles such as the red section of vastus lateralis [277 +/- 24 and 153 +/- 13 (SE) ml.min-1.100 g-1 for Eut and Hypo, respectively; P < 0.01] and vastus intermedius (317 +/- 32 and 187 +/- 20 ml.min-1.100 g-1 for Eut and Hypo, respectively; P < 0.01) muscles. Training (THypo) did not normalize these flows (168 +/- 24 and 181 +/- 24 ml.min-1.100 g-1 for red section of vastus lateralis and vastus intermedius muscles, respectively). Blood flows to low oxidative muscle, such as the white section of vastus lateralis muscle, were similar among groups (21 +/- 5, 25 +/- 4, and 34 +/- 7 ml.min-1.100 g-1 for Eut, Hypo, and THypo, respectively; P = NS). These findings indicate that hypothyroidism is associated with reduced blood flow to skeletal muscle during exercise, suggesting that impaired delivery of nutrients to and/or removal of metabolites from skeletal muscle contributes to the poor exercise tolerance characteristic of hypothyroidism.

scholarly journals Cardiovascular and skeletal muscle health with lifelong exercise

2018 ◽  
Vol 125 (5) ◽  
pp. 1636-1645 ◽  
Author(s):  
Kevin J. Gries ◽  
Ulrika Raue ◽  
Ryan K. Perkins ◽  
Kaleen M. Lavin ◽  
Brittany S. Overstreet ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Aerobic Exercise ◽  
Muscle Biopsy ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Metabolic Phenotype ◽  
Vastus Lateralis Muscle ◽  
Metabolic Fitness ◽  
Lifelong Exercise

The purpose of this study was to examine the effects of aerobic lifelong exercise (LLE) on maximum oxygen consumption (V̇o2max) and skeletal muscle metabolic fitness in trained women ( n = 7, 72 ± 2 yr) and men ( n = 21, 74 ± 1 yr) and compare them to old, healthy nonexercisers (OH; women: n = 10, 75 ± 1 yr; men: n = 10, 75 ± 1 yr) and young exercisers (YE; women: n = 10, 25 ± 1 yr; men: n = 10, 25 ± 1 yr). LLE men were further subdivided based on intensity of lifelong exercise and competitive status into performance (LLE-P, n = 14) and fitness (LLE-F, n = 7). On average, LLE exercised 5 day/wk for 7 h/wk over the past 52 ± 1 yr. Each subject performed a maximal cycle test to assess V̇o2maxand had a vastus lateralis muscle biopsy to examine capillarization and metabolic enzymes [citrate synthase, β-hydroxyacyl-CoA dehydrogenase (β-HAD), and glycogen phosphorylase]. V̇o2maxhad a hierarchical pattern (YE > LLE > OH, P < 0.05) for women (44 ± 2 > 26 ± 2 > 18 ± 1 ml·kg−1·min−1) and men (53 ± 3 > 34 ± 1 > 22 ± 1 ml·kg−1·min−1) and was greater ( P < 0.05) in LLE-P (38 ± 1 ml·kg−1·min−1) than LLE-F (27 ± 2 ml·kg−1·min−1). LLE men regardless of intensity and women had similar capillarization and aerobic enzyme activity (citrate synthase and β-HAD) as YE, which were 20%–90% greater ( P < 0.05) than OH. In summary, these data show a substantial V̇o2maxbenefit with LLE that tracked similarly between the sexes, with further enhancement in performance-trained men. For skeletal muscle, 50+ years of aerobic exercise fully preserved capillarization and aerobic enzymes, regardless of intensity. These data suggest that skeletal muscle metabolic fitness may be easier to maintain with lifelong aerobic exercise than more central aspects of the cardiovascular system.NEW & NOTEWORTHY Lifelong exercise (LLE) is a relatively new and evolving area of study with information especially limited in women and individuals with varying exercise intensity habits. These data show a substantial maximal oxygen consumption benefit with LLE that tracked similarly between the sexes. Our findings contribute to the very limited skeletal muscle biopsy data from LLE women (>70 yr), and similar to men, revealed a preserved metabolic phenotype comparable to young exercisers.

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