Estimation of muscle fiber composition in vastus lateralis using performances of 50-m sprint and 12-min run

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.

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Muscle hypertrophy in prediabetic men after 16 wk of resistance training

Journal of Applied Physiology ◽

10.1152/japplphysiol.00023.2017 ◽

2017 ◽

Vol 123 (4) ◽

pp. 894-901 ◽

Cited By ~ 8

Author(s):

Charles A. Stuart ◽

Michelle L. Lee ◽

Mark A. South ◽

Mary E. A. Howell ◽

Michael H. Stone

Keyword(s):

Resistance Training ◽

Muscle Fiber ◽

Muscle Hypertrophy ◽

Vastus Lateralis ◽

Fiber Content ◽

Progressive Resistance Training ◽

Fiber Composition ◽

Obese Subjects ◽

Increased Strength ◽

Fast Twitch

Resistance training of healthy young men typically results in muscle hypertrophy and a shift in vastus lateralis composition away from type IIx fibers to an increase in IIa fiber content. Our previous studies of 8 wk of resistance training found that many metabolic syndrome men and women paradoxically increased IIx fibers with a decrease in IIa fibers. To confirm the hypothesis that obese subjects might have muscle remodeling after resistance training very different from healthy lean subjects, we subjected a group of nine obese male volunteers to progressive resistance training for a total of 16 wk. In these studies, weight loss was discouraged so that muscle changes would be attributed to the training alone. Detailed assessments included comparisons of histological examinations of needle biopsies of vastus lateralis muscle pretraining and at 8 and 16 wk. Prolonging the training from 8 to 16 wk resulted in increased strength, improved body composition, and more muscle fiber hypertrophy, but euglycemic clamp-quantified insulin responsiveness did not improve. Similar to prior studies, muscle fiber composition shifted toward more fast-twitch type IIx fibers (23 to 42%). Eight weeks of resistance training increased the muscle expression of phosphorylated Akt2 and mTOR. Muscle GLUT4 expression increased, although insulin receptor and IRS-1 expression did not change. We conclude that resistance training of prediabetic obese subjects is effective at changing muscle, resulting in fiber hypertrophy and increased type IIx fiber content, and these changes continue up to 16 wk of training.NEW & NOTEWORTHY Obese, insulin-resistant men responded to 16 wk of progressive resistance training with muscle hypertrophy and increased strength and a shift in muscle fiber composition toward fast-twitch, type IIx fibers. Activation of muscle mTOR was increased by 8 wk but did not increase further at 16 wk despite continued augmentation of peak power and rate of force generation.

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Relationships between sprint performances and muscle fiber composition and muscle capillary supply of m. vastus lateralis in sprinters

Taiikugaku kenkyu (Japan Journal of Physical Education Health and Sport Sciences) ◽

10.5432/jjpehss.kj00003391761 ◽

1990 ◽

Vol 35 (3) ◽

pp. 253-260

Author(s):

Kazunori Asaba ◽

Shigeru Katsuta ◽

Kaoru Takamatsu ◽

Ken Miyashita

Keyword(s):

Muscle Fiber ◽

Vastus Lateralis ◽

Capillary Supply ◽

Fiber Composition

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Electrical Stimulation Frequency and Skeletal Muscle Characteristics: Effects on Force and Fatigue

European Journal of Translational Myology ◽

10.4081/ejtm.2017.6816 ◽

2017 ◽

Vol 27 (4) ◽

Cited By ~ 7

Author(s):

Maria Vromans ◽

Pouran Faghri

Keyword(s):

Electrical Stimulation ◽

Vastus Lateralis ◽

Voluntary Contraction ◽

Current Intensity ◽

Muscle Size ◽

Emg Activity ◽

Abductor Pollicis Brevis ◽

Fiber Composition ◽

Initial Drop ◽

Initial Force

This investigation aimed to determine the force and muscle surface electromyography (EMG) responses to different frequencies of electrical stimulation (ES) in two groups of muscles with different size and fiber composition (fast- and slow-twitch fiber proportions) during a fatigue-inducing protocol. Progression towards fatigue was evaluated in the abductor pollicis brevis (APB) and vastus lateralis (VL) when activated by ES at three frequencies (10, 35, and 50Hz). Ten healthy adults (mean age: 23.2 ± 3.0 years) were recruited; participants signed an IRB approved consent form prior to participation. Protocols were developed to 1) identify initial ES current intensity required to generate the 25% maximal voluntary contraction (MVC) at each ES frequency and 2) evaluate changes in force and EMG activity during ES-induced contraction at each frequency while progressing towards fatigue. For both muscles, stimulation at 10Hz required higher current intensity of ES to generate the initial force. There was a significant decline in force in response to ES-induced fatigue for all frequencies and for both muscles (p<0.05). However, the EMG response was not consistent between muscles. During the progression towards fatigue, the APB displayed an initial drop in force followed by an increase in EMG activity and the VL displayed a decrease in EMG activity for all frequencies. Overall, it appeared that there were some significant interactions between muscle size and fiber composition during progression towards fatigue for different ES frequencies. It could be postulated that muscle characteristics (size and fiber composition) should be considered when evaluating progression towards fatigue as EMG and force responses are not consistent between muscles.

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Compensatory muscle fiber hypertrophy in elderly men

Journal of Applied Physiology ◽

10.1152/jappl.1992.73.3.812 ◽

1992 ◽

Vol 73 (3) ◽

pp. 812-816 ◽

Cited By ~ 68

Author(s):

A. Aniansson ◽

G. Grimby ◽

M. Hedberg

Keyword(s):

Muscle Strength ◽

Muscle Fiber ◽

Citrate Synthase ◽

Biceps Brachii ◽

Vastus Lateralis ◽

Cell Mass ◽

Knee Extension ◽

Type I ◽

Type Ii ◽

Elderly Men

Muscle strength and muscle morphology have been studied three times during a period of 11 yr in nine elderly men. On the last occasion the average age was 80.4 (range 79–82) yr. Body cell mass decreased by 6% and muscle strength for knee extension, measured by means of isometric and concentric isokinetic (30–60 degrees/s) recordings, declined by 25–35% over the 11-yr period. Between 76 and 80 yr of age only the isokinetic strength for 30 degrees/s decreased significantly. Muscle fiber composition in the vastus lateralis did not change between 69 and 76 yr of age, but there was a significant reduction in the proportion of type IIb fibers from 76 to 80 yr. The decrease in type II fiber areas was not significant between 69 and 76 yr of age (as in a larger sample from the same population), but a significant increase in both type I and type II fiber areas was recorded from 76 to 80 yr of age and biceps brachii showed similar tendencies. In the same period, the enzymatic activities of myokinase and lactate dehydrogenase subsided in the vastus lateralis, but there was no change for triose phosphate dehydrogenase, 3-hydroxy-CoA-dehydrogenase, and citrate synthase. The muscle fiber hypertrophy in this group of elderly men with maintained physical activity between 76 and 80 yr of age is interpreted as a compensatory adaptation for the loss of motor units. In addition, the adaptation with respect to oxidative capacities seems to be maintained at this age.

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Effect of heavy-resistance exercise training on muscle fiber composition in young rats

Journal of Applied Physiology ◽

10.1152/jappl.1990.69.2.434 ◽

1990 ◽

Vol 69 (2) ◽

pp. 434-437 ◽

Cited By ~ 42

Author(s):

K. E. Yarasheski ◽

P. W. Lemon ◽

J. Gilloteaux

Keyword(s):

Exercise Training ◽

Resistance Exercise ◽

Muscle Fiber ◽

Rectus Femoris ◽

Type I ◽

Resistance Exercise Training ◽

Fiber Composition ◽

Deep Region ◽

Heavy Resistance Exercise ◽

Type I Fibers

The purpose of this investigation was to determine whether heavy-resistance exercise training alters the skeletal muscle fiber composition of young rats. Ten male Long Evans rats (3 wk old) were trained to lift progressively heavier weights, which were secured to the rats' tails, while they ascended a 40-cm 90 degree mesh incline 20 times/day 5 days/wk for a food reward. After 8 wk of training, they lifted 406 +/- 19 (SD) g in addition to their body weight (261 +/- 9 g). Compared with 10 sedentary pair-fed rats, no hypertrophy of forelimb muscles (biceps brachii and brachialis) was observed, but rectus femoris wet and dry weights were greater (P less than 0.01) in the trained group. In the deep region of the rectus femoris, type I fiber area was similar between groups, but the trained rats had both a lower (P less than 0.05) percentage of type I fibers and a smaller (P less than 0.05) portion of the total area occupied by type I fibers. The percentage of type IIb fibers in the deep region of the rectus femoris was also similar between groups, but the portion of the deep area composed of type IIb fibers was greater (P less than 0.05) in the trained rats. In the superficial region of the rectus femoris, the trained rats' type IIb fibers were larger (P less than 0.01) and occupied a greater (P less than 0.05) portion of the superficial muscle area.(ABSTRACT TRUNCATED AT 250 WORDS)

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Alteration of muscle fiber composition linking to insulin resistance and hypertension in fructose-fed rats

American Journal of Hypertension ◽

10.1016/s0895-7061(99)00025-4 ◽

1999 ◽

Vol 12 (6) ◽

pp. 596-602 ◽

Cited By ~ 30

Author(s):

K Higashiura

Keyword(s):

Insulin Resistance ◽

Muscle Fiber ◽

Fiber Composition

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Electrolytes in slow and fast muscle fibers of humans at rest and with dynamic exercise

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1983.245.1.r25 ◽

1983 ◽

Vol 245 (1) ◽

pp. R25-R31 ◽

Cited By ~ 17

Author(s):

G. Sjogaard

Keyword(s):

Skeletal Muscles ◽

Vastus Lateralis ◽

Fiber Types ◽

Triceps Brachii ◽

Sodium Potassium ◽

Mean Values ◽

Fiber Composition ◽

Slow Twitch ◽

Fast Twitch ◽

Muscle Fiber Membrane

Sodium, potassium, and magnesium were analyzed in human slow-twitch (ST) and fast-twitch (FT) skeletal muscles. In contrast to other species, no relation was found between fiber composition and electrolyte distribution. In soleus (S), vastus lateralis (VL), and triceps brachii (TB) the overall mean values for 6 men and 6 women were 44 mmol K/100 g dry wt and 11 mmol Na/100 g dry wt; the intracellular concentrations were 161 mmol K/l and 26 mmol Na/l with no differences between the muscles. Analysis of fragments of single ST and FT fibers from each of the muscles also showed no difference between the fiber types in Na and K content. Small differences were seen between the muscles with regard to Mg, but these were not related to fiber composition compared with other species. During exercise to exhaustion (3 bouts of bicycling for 3 min at 325-395 W, 6 men) the extracellular electrolyte concentrations for Na, K, and Mg increased from 134 to 140, 4.5 to 5.8, and 0.75 to 0.87 mmol/l, respectively (P less than 0.05). In VL Na content increased from 9.8 to 16.5 mmol/100 g dry wt, while intracellular [Na] remained constant. In contrast, intracellular [K] decreased from 161 to 141 mmol/l (P less than 0.05). No such changes occurred in TB. In concert with other studies the present changes in electrolytes in the working muscles indicate that muscle fatigue may be related to changes at the muscle fiber membrane.

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Carnitine metabolism in human muscle fiber types during submaximal dynamic exercise

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.3.1061 ◽

1996 ◽

Vol 80 (3) ◽

pp. 1061-1064 ◽

Cited By ~ 27

Author(s):

D. Constantin-Teodosiu ◽

S. Howell ◽

P. L. Greenhaff

Keyword(s):

Muscle Fiber ◽

Fiber Type ◽

Vastus Lateralis ◽

Group Formation ◽

Free Carnitine ◽

Muscle Fiber Types ◽

Type I ◽

Fiber Types ◽

Carnitine Metabolism ◽

Type I Fibers

The effect of prolonged exhaustive exercise on free carnitine and acetylcarnitine concentrations in mixed-fiber skeletal muscle and in type I and II muscle fibers was investigated in humans. Needle biopsy samples were obtained from the vastus lateralis of six subjects immediately after exhaustive one-legged cycling at approximately 75% of maximal O2 uptake from both the exercised and nonexercised (control) legs. In the resting (control) leg, there was no difference in the free carnitine concentration between type I and II fibers (20.36 +/- 1.25 and 20.51 +/- 1.16 mmol/kg dry muscle, respectively) despite the greater potential for fat oxidation in type I fibers. However, the acetylcarnitine concentration was slightly greater in type I fibers (P < 0.01). During exercise, acetylcarnitine accumulation occurred in both muscle fiber types, but accumulation was greatest in type I fibers (P < 0.005). Correspondingly, the concentration of free carnitine was significantly lower in type I fibers at the end of exercise (P < 0.001). The sum of free carnitine and acetylcarnitine concentrations in type I and II fibers at rest was similar and was unchanged by exercise. In conclusion, the findings of the present study support the suggestion that carnitine buffers excess acetyl group formation during exercise and that this occurs in both type I and II fibers. However, the greater accumulation of acetylcarnitine in type I fibers during prolonged exercise probably reflects the greater mitochondrial content of this fiber type.

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