Short-Term Training, Muscle Glycogen, and Cycle Endurance

1995 ◽  
Vol 20 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Howard J. Green ◽  
Marg Ball-Burnett ◽  
Steve Symon ◽  
Sue Grant ◽  
Greg Jamieson
Keyword(s):  
Vastus Lateralis ◽  
Endurance Performance ◽  
Control Group ◽  
Vastus Lateralis Muscle ◽  
Short Term ◽  
Exercise Time ◽  
Glycogen Concentration ◽  
Prolonged Fatigue ◽  
Performance Adaptation ◽  
Cycle Endurance

The objective of this study was to test the hypothesis that the increased glycogen concentration found in the working muscles following short-term training would result in an increase in endurance performance. Endurance performance was examined in 8 active but untrained males who cycled until fatigue at 65% [Formula: see text]max prior to and following 3 consecutive days of training. Training consisted of cycling for 2 hrs a day at the same power output used in the prolonged fatigue trials. A 39% increase in cycle time, from 103 ± 7.7 to 143 ± 14 min (p < 0.05), was observed following training. At fatigue prior to training, glycogen concentration in the vastus lateralis muscle was depleted by 75% (317 ± 17 to 78.8 ± 32 mmol∙glucosyl units∙kg−1 d.w). Following training, glycogen concentration at a comparable work time was 2.3 times higher. The elevated glycogen level following training was due both to higher glycogen at rest and during exercise. The energy cost of the activity as measured by the [Formula: see text] at selected intervals was unchanged with training. No change (p > 0.05) in exercise time was observed in a control group who were subjected to similar exercise protocols approximately 1 to 2 weeks apart. It is concluded that short-term training at least in untrained individuals ([Formula: see text]max averaging 43.6 ± 2.9 ml∙kg−1∙min−1) substantially elevates submaximal exercise tolerance and that the increase in resistance to fatigue is related to the elevated availability of glycogen. Key words: endurance performance, adaptation, carbohydrate, vastus lateralis

Muscle glycogen availability and temperature regulation in humans

1989 ◽  
Vol 66 (1) ◽  
pp. 72-78 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Temperature Regulation ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Before And After ◽  
Muscle Groups

The effects of intramuscular glycogen availability on human temperature regulation were studied in eight seminude subjects immersed in 18 degrees C water for 90 min or until rectal temperature (Tre) decreased to 35.5 degrees C. Each subject was immersed three times over a 3-wk period. Each immersion followed 2.5 days of a specific dietary and/or exercise regimen designed to elicit low (L), normal (N), or high (H) glycogen levels in large skeletal muscle groups. Muscle glycogen concentration was determined in biopsies taken from the vastus lateralis muscle before and after each immersion. Intramuscular glycogen concentration before the immersion was significantly different among the L, N, and H trials (P less than 0.01), averaging 247 +/- 15, 406 +/- 23, and 548 +/- 42 (SE) mmol glucose units.kg dry muscle-1, respectively. The calculated metabolic heat production during the first 30 min of immersion was significantly lower during L compared with N or H (P less than 0.05). The rate at which Tre decreased was more rapid during the L immersion than either N or H (P less than 0.05), and the time during the immersion at which Tre first began to decrease also appeared sooner during L than N or H. The results suggest that low skeletal muscle glycogen levels are associated with more rapid body cooling during water immersion in humans. Higher than normal muscle glycogen levels, however, do not increase cold tolerance.

Effect of endurance training on muscle activation and force sensation

1995 ◽  
Vol 73 (12) ◽  
pp. 1765-1773 ◽  
Author(s):  
E. Cafarelli ◽  
F. Liebesman ◽  
J. Kroon
Keyword(s):  
Endurance Training ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Endurance Performance ◽  
Motor Units ◽  
Control Group ◽  
Reduction In Force ◽  
Leg Cycling ◽  
Before And After ◽  
And Control

One of the consequences of endurance training is a reduction in force sensation in trained muscles at any exercise intensity. To study the central and peripheral contributions to this adaptation, we trained six male subjects with single-leg cycling at 60% [Formula: see text] peak (30 min/day × 3 days/week × 8 weeks); six others were matched controls. Measurements were made during separate 20-min, single-leg rides at 70% pre-training [Formula: see text] peak, with trained (TR), untrained (UT), and control (CT) legs, before and after training. No pre–post differences were observed in the control group. [Formula: see text] peak increased 18% (p < 0.05) in the TR leg and 6% (p < 0.05) in the UT leg of the trained subjects. Force sensation was significantly less in both the TR (70%; p < 0.05) and UT (50%; p < 0.05) legs during 20 min of single-leg cycling after training. Vastus lateralis EMG, plasma lactate, and heart rate were all significantly (p < 0.05) lower when cycling with either the TR or UT leg, which were both lower than when cycling with the CT leg, at the end of each 20-min ride. These data reflect an intramuscular environment that is better adapted to endurance performance by virtue of both central and peripheral mechanisms. Thus, there is less need to recruit additional motor units to maintain the same power output, and this reduced motor outflow leads to a decline in force sensation.Key words: kinesthesia, proprioception, electromyography, single-leg training, endurance training.

Effect of exercise on insulin action in human skeletal muscle

1989 ◽  
Vol 66 (2) ◽  
pp. 876-885 ◽  
Author(s):  
E. A. Richter ◽  
K. J. Mikines ◽  
H. Galbo ◽  
B. Kiens
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Insulin Action ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Femoral Vein ◽  
Glycogen Synthesis ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Local Contraction

The effect of 1 h of dynamic one-legged exercise on insulin action in human muscle was studied in 6 healthy young men. Four hours after one-legged knee extensions, a three-step sequential euglycemic hyperinsulinemic clamp combined with arterial and bilateral femoral vein catheterization was performed. Increased insulin action on glucose uptake was found in the exercised compared with the rested thigh at mean plasma insulin concentrations of 23, 40, and 410 microU/ml. Furthermore, prior contractions directed glucose uptake toward glycogen synthesis and increased insulin effects on thigh O2 consumption and at some insulin concentrations on potassium exchange. In contrast, no change in insulin effects on limb exchange of free fatty acids, glycerol, alanine or tyrosine were found after exercise. Glycogen concentration in rested vastus lateralis muscle did not increase measurably during the clamp even though indirect estimates indicated net glycogen synthesis. In contrast, in exercised muscle estimated and biopsy-verified increases in muscle glycogen concentration agreed. Local contraction-induced increases in insulin sensitivity and responsiveness play an important role in postexercise recovery of human skeletal muscle.

scholarly journals PPARGC1A rs8192678 and NRF1 rs6949152 Polymorphisms Are Associated with Muscle Fiber Composition in Women

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1012
Author(s):  
Thomas Yvert ◽  
Eri Miyamoto-Mikami ◽  
Takuro Tobina ◽  
Keisuke Shiose ◽  
Ryo Kakigi ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Vastus Lateralis ◽  
Endurance Performance ◽  
Individual Variability ◽  
Lower Proportion ◽  
Vastus Lateralis Muscle ◽  
Mhc I ◽  
Fiber Composition ◽  
Individual Variations ◽  
Health Related

PPARGC1A rs8192678 G/A (Gly482Ser) and NRF1 rs6949152 A/G polymorphisms have been associated with endurance athlete status, endurance performance phenotypes, and certain health-related markers of different pathologies such as metabolic syndrome, diabetes, and dyslipidemia. We hypothesized that they could be considered interesting candidates for explaining inter-individual variations in muscle fiber composition in humans. We aimed to examine possible associations of these polymorphisms with myosin heavy-chain (MHC) isoforms as markers of muscle fiber compositions in vastus lateralis muscle in a population of 214 healthy Japanese subjects, aged between 19 and 79 years. No significant associations were found in men for any measured variables. In contrast, in women, the PPARGC1A rs8192678 A/A genotype was significantly associated with a higher proportion of MHC-I (p = 0.042) and with a lower proportion of MHC-IIx (p = 0.033), and the NRF1 rs6949152 AA genotype was significantly associated with a higher proportion of MHC-I (p = 0.008) and with a lower proportion of MHC IIx (p = 0.035). In women, the genotype scores of the modes presenting the most significant results for PPARGC1A rs8192678 G/A (Gly482Ser) and NRF1 rs6949152 A/G polymorphisms were significantly associated with MHC-I (p = 0.0007) and MHC IIx (p = 0.0016). That is, women with combined PPARGC1A A/A and NRF1 A/A genotypes presented the highest proportion of MHC-I and the lowest proportion of MHC-IIx, in contrast to women with combined PPARGC1A GG+GA and NRF1 AG+GG genotypes, who presented the lowest proportion of MHC-I and the highest proportion of MHC-IIx. Our results suggest possible associations between these polymorphisms (both individually and in combination) and the inter-individual variability observed in muscle fiber composition in women, but not in men.

Gene variants related to the power performance of the Lithuanian athletes

2011 ◽  
Vol 6 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Valentina Ginevičienė ◽  
Erinija Pranckevičienė ◽  
Kazys Milašius ◽  
Vaidutis Kučinskas
Keyword(s):  
Muscle Power ◽  
Elite Athletes ◽  
Endurance Performance ◽  
Control Group ◽  
Power Performance ◽  
Phenotypic Characteristics ◽  
Short Term ◽  
Intermediate Phenotypes ◽  
Genotype Frequencies ◽  
Group Success

AbstractACE (I/D), ACTN3 (R/X), PPARGC1A (Gly482Ser) and PPARA (G/C) polymorphisms have been linked to the success in power-oriented sports through the intermediate phenotypes. The study involved 193 Lithuanian elite athletes and 250 controls. The measured phenotypic variables included short-term explosive muscle power (STEMP) and anaerobic alactic maximum power (AAMP). ACE DD genotype was more common among endurance athletes compared to the power athletes. The ACTN3 genotype frequencies of the elite athletes differed from those of non-elite athletes; however, there were no differences among the athletes and the control group across the PPARGC1A Gly482Ser genotypes. The frequency of PPARA CC genotype increased with the growing skill level of athletes (non-elite 2%, sub-elite 7.7%, elite 11.6%). The STEMP and AAMP were higher in the males than females and they were also higher in the power-oriented group compared to the endurance sports group. Success in power sports can be attributed to the ACE II, PPARGC1A SerSer, PPARA CC genotype in association with phenotypic characteristics such as AAMP and STEMP. ACTN3 XX genotype may not be critical but rather additive to endurance performance. The results show that high muscle power depends on both environmental and genetic factors.

Resistance exercise acutely increases MHC and mixed muscle protein synthesis rates in 78–84 and 23–32 yr olds

2000 ◽  
Vol 278 (4) ◽  
pp. E620-E626 ◽  
Author(s):  
Debbie L. Hasten ◽  
Jina Pak-Loduca ◽  
Kathleen A. Obert ◽  
Kevin E. Yarasheski
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Vastus Lateralis ◽  
Weight Lifting ◽  
Synthesis Rate ◽  
Vastus Lateralis Muscle ◽  
Short Term ◽  
Mixed Protein

We determined whether short-term weight-lifting exercise increases the synthesis rate of the major contractile proteins, myosin heavy chain (MHC), actin, and mixed muscle proteins in nonfrail elders and younger women and men. Fractional synthesis rates of mixed, MHC, and actin proteins were determined in seven healthy sedentary 23- to 32-yr-old and seven healthy 78- to 84-yr-old participants in paired studies done before and at the end of a 2-wk weight-lifting program. The in vivo rate of incorporation of 1-[13C]leucine into vastus lateralis MHC, actin, and mixed proteins was determined using a 14-h constant intravenous infusion of 1-[13C]leucine. Before exercise, the mixed and MHC fractional synthetic rates were lower in the older than in the younger participants ( P ≤ 0.04). Baseline actin protein synthesis rates were similar in the two groups ( P = not significant). Over a 2-wk period, participants completed ten 1- to 1.5-h weight-lifting exercise sessions: 2–3 sets per day of 9 exercises, 8–12 repetitions per set, at 60–90% of maximum voluntary muscle strength. At the end of exercise, MHC and mixed protein synthetic rates increased in the younger (88 and 121%) and older participants (105 and 182%; P < 0.001 vs. baseline). These findings indicate that MHC and mixed protein synthesis rates are reduced more than actin in advanced age. Similar to that of 23–32 yr olds, the vastus lateralis muscle in 78–84 yr olds retains the capacity to increase MHC and mixed protein synthesis rates in response to short-term resistance exercise.

Increases in human skeletal muscle Na(+)-K(+)-ATPase concentration with short-term training

1993 ◽  
Vol 264 (6) ◽  
pp. C1538-C1541 ◽  
Author(s):  
H. J. Green ◽  
E. R. Chin ◽  
M. Ball-Burnett ◽  
D. Ranney
Keyword(s):  
Skeletal Muscle ◽  
Aerobic Power ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Ouabain Binding ◽  
Short Term ◽  
Vo2 Max ◽  
Continuous Exercise ◽  
Sufficient Intensity ◽  
K Concentration

To investigate the effect of short-term training on Na(+)-K(+)-adenosine triphosphatase (ATPase) concentration in skeletal muscle and on plasma K+ homeostasis during exercise, 9 subjects performed cycle exercise for 2 h per day for 6 consecutive days at 65% of maximal aerobic power (VO2 max). Na(+)-K(+)-ATPase concentration determined from biopsies obtained from the vastus lateralis muscle using the [3H]ouabain-binding technique increased 13.6% (P < 0.05) as a result of the training (339 +/- 16 vs. 385 +/- 19 pmol/g wet wt, means +/- SE). Increases in Na(+)-K(+)-ATPase concentration were accompanied by a small but significant increase in VO2 max (3.36 +/- 0.16 vs. 3.58 +/- 0.13 l/min). The increase in arterialized plasma K+ concentration and plasma K+ content determined during continuous exercise at three different intensities (60, 79, and 94% VO2 max) was depressed (P < 0.05) following training. These results indicate that not only is training capable of inducing an upregulation in sarcolemmal Na(+)-K(+)-ATPase concentration in humans, but provided that the exercise is of sufficient intensity and duration, the upregulation can occur within the first week of training. Moreover, our findings are consistent with the notion that the increase in Na(+)-K(+)-ATPase pump concentration attenuates the loss of K+ from the working muscle.

A moderate glycemic meal before endurance exercise can enhance performance

1998 ◽  
Vol 84 (1) ◽  
pp. 53-59 ◽  
Author(s):  
John P. Kirwan ◽  
Donal O’Gorman ◽  
William J. Evans
Keyword(s):  
Dietary Fiber ◽  
Endurance Exercise ◽  
Glycemic Index ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Time To Exhaustion ◽  
Vastus Lateralis Muscle ◽  
Exercise Time ◽  
Breakfast Cereals ◽  
Lateralis Muscle

Kirwan, John P., Donal O’Gorman, and William J. Evans.A moderate glycemic meal before endurance exercise can enhance performance. J. Appl. Physiol. 84(1): 53–59, 1998.—The purpose of this study was to determine whether presweetened breakfast cereals with various fiber contents and a moderate glycemic index optimize glucose availability and improve endurance exercise performance. Six recreationally active women ate 75 g of available carbohydrate in the form of breakfast cereals: sweetened whole-grain rolled oats (SRO, 7 g of dietary fiber) or sweetened whole-oat flour (SOF, 3 g of dietary fiber) and 300 ml of water or water alone (Con). The meals were provided 45 min before semirecumbent cycle ergometer exercise to exhaustion at 60% of peak O2consumption (V˙o2 peak). Diet and physical activity were controlled by having the subjects reside in the General Clinical Research Center for 2 days before each trial. Blood samples were drawn from an antecubital vein for glucose, free fatty acid (FFA), glycerol, insulin, epinephrine, and norepinephrine determination. Breath samples were obtained at 15-min intervals after meal ingestion and at 30-min intervals during exercise. Muscle glycogen concentration was determined from biopsies taken from the vastus lateralis muscle before the meal and immediately after exercise. Plasma FFA concentrations were lower ( P < 0.05) during the SRO and SOF trials for the first 60 and 90 min of exercise, respectively, than during the Con trial. Respiratory exchange ratios were higher ( P < 0.05) at 90 and 120 min of exercise for the SRO and SOF trials, respectively, than for the Con trial. At exhaustion, glucose, insulin, FFA, glycerol, epinephrine, and norepinephrine concentrations, respiratory exchange ratio, and muscle glycogen use in the vastus lateralis muscle were similar for all trials. Exercise time to exhaustion was 16% longer ( P < 0.05) during the SRO than during the Con trial: 266.5 ± 13 and 225.1 ± 8 min, respectively. There was no difference in exercise time for the SOF (250.8 ± 12) and Con trials. We conclude that eating a meal with a high dietary fiber content and moderate glycemic index 45 min before prolonged moderately intense exercise significantly enhances exercise capacity.

scholarly journals Dynamic Oromandibular Reconstructions Using Chimeric Fibular and Gracilis or Vastus Lateralis Free Flaps

2020 ◽  
Vol 05 (02) ◽  
pp. e36-e42
Author(s):  
Min Ji Kim ◽  
Jong Woo Choi ◽  
Woo Shik Jeong ◽  
Soon Yuhl Nam ◽  
Seung Ho Choi
Keyword(s):  
Free Flap ◽  
Vastus Lateralis ◽  
Retrospective Chart Review ◽  
Free Flaps ◽  
Control Group ◽  
Vastus Lateralis Muscle ◽  
Free Fibular Flap ◽  
Dynamic Group ◽  
Fibular Flap ◽  
Oromandibular Reconstruction

Abstract Background Despite efforts of head and neck functional reconstruction, anatomic restoration has been used until now. This article describes our experience of using a chimeric free fibular osteocutaneous flap conjoined with a functional muscle free flap, defined as dynamic oromandibular reconstruction. Methods Through a retrospective chart review, four consecutive patients who underwent reconstruction with a total fibular free flap were included. The former two patients underwent reconstruction using a conventional osteocutaneous free fibular flap. The latter two patients had an oromandibular defect after cancer resection and underwent dynamic oromandibular reconstruction with a chimeric free fibular flap conjoined with a gracilis free flap or vastus lateralis muscle free flap. Results In the speech analysis, the dynamic group revealed a satisfactory tongue movement. Protrusion and lateralization were the most different movement changes. The tongue range of motion score was 62.5 in the dynamic group and 25.0 in the control group. On the dynamic magnetic resonance imaging, the contact of the soft palate with the tongue was excellent, and the epiglottis closure during deglutition was complete. In the three-dimensional volumetric analysis of mandibular aesthetic contouring, the dynamic group showed a much smaller difference in hemifacial volume, with a difference of 73.7 mL in the dynamic group and 101.76 mL in the control group. Conclusion This study is a preliminary trial of dynamic oromandibular reconstruction using chimeric free fibular flaps with functional muscle transfer. We demonstrated the possibility of dynamic oromandibular reconstruction, which enhanced more functional aspects in the patients in this study.

Variability of triacylglycerol content in human skeletal muscle biopsy samples

1996 ◽  
Vol 81 (3) ◽  
pp. 1150-1155 ◽  
Author(s):  
P. S. Wendling ◽  
S. J. Peters ◽  
G. J. Heigenhauser ◽  
L. L. Spriet
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Exercise Time ◽  
Skeletal Muscle Biopsy ◽  
Time Points ◽  
Freeze Dried ◽  
Triacylglycerol Content ◽  
Rest And Exercise

The variability of the triacylglycerol store in human skeletal muscle (TGm) was examined using the needle biopsy technique. In 13 subjects, three biopsies were sampled from the vastus lateralis muscle of one leg at rest and after 90 min of cycling at 65% of maximal O2 uptake on one or two occasions. Visible fat and blood were removed before the samples were frozen, and remaining blood, connective tissue, and fat were removed from freeze-dried fiber bundles. TGm content was measured in two aliquots of powdered muscle from each biopsy. Within-biopsy variability was low at 6%. Despite precautions, many biopsies from inactive subjects were contaminated with adipose tissue. The TGm between-biopsy coefficient of variation (CV) was 23.5 +/- 14.6% (SD, n = 24) for rest and exercise time points where three noncontaminated biopsies existed. The between-biopsy variability at rest (19.8 +/- 7.9%, n = 10) was not significantly different from that at exercise (26.1 +/- 17.4%, n = 14). The muscle glycogen between-biopsy CV for rest and exercise time points was 10.0 +/- 10.3%. The resting TGm content was 26.3 +/- 4.3 mmol/kg dry muscle, and the net utilization during the 90 min of exercise was less than the between-biopsy variability. It is concluded that the TGm store measured in repeated biopsies of human skeletal muscle is variable, with a CV of 20-26%. Therefore, because of this high variability, only changes greater than approximately 24% of resting TGm content may be considered meaningful.

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