Influence of prolonged endurance cycling and recovery diet on intramuscular triglyceride content in trained males

Intramuscular triglycerides (IMTG) are assumed to form an important substrate source during prolonged endurance exercise in trained males. This study investigated the effects of endurance exercise and recovery diet on IMTG content in vastus lateralis muscle. Nine male cyclists were provided with a standardized diet for 3 days, after which they performed a 3-h exercise trial at a 55% maximum workload. Before and immediately after exercise and after 24 and 48 h of recovery, magnetic resonance spectroscopy (MRS) was performed to quantitate IMTG content. Muscle biopsies were taken after 48 h of recovery to determine IMTG content by using quantitative fluorescence microscopy. The entire procedure was performed two times; in one trial, a normal diet containing 39% energy (En%) as fat was provided (NF) and in the other a typical carbohydrate-rich athlete's diet (LF: 24 En% fat) was provided. During exercise, IMTG content decreased by 21.4 ± 3.1%. During recovery, IMTG content increased significantly in the NF trial only, reaching preexercise levels within 48 h. In accord with MRS, fluorescence microscopy showed significantly higher IMTG content in the NF compared with the LF trial, with differences restricted to the type I muscle fibers (2.1 ± 0.2 vs. 1.4 ± 0.2% area lipid staining, respectively). In conclusion, IMTG content in the vastus lateralis muscle declines significantly during prolonged endurance exercise in male cyclists. When a normal diet is used, IMTG contents are subsequently repleted within 48 h of postexercise recovery. In contrast, IMTG repletion is impaired substantially when a typical, carbohydrate-rich athlete's diet is used. Data obtained by quantitative fluorescence microscopy correspond well with MRS results, implying that both are valid methods to quantify IMTG content.

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Calcium and strontium contractile activation properties of single skinned skeletal muscle fibres from elderly women 66-90 years of age

10.1101/2021.11.08.466855 ◽

2021 ◽

Author(s):

Sue M Ronaldson ◽

George D Stephenson ◽

Stewart I Head

Keyword(s):

Skeletal Muscle ◽

Elderly Women ◽

Vastus Lateralis ◽

Muscle Fibres ◽

Vastus Lateralis Muscle ◽

Type I ◽

Lateralis Muscle ◽

Slow Twitch ◽

Skeletal Muscle Fibres ◽

Muscle Biopsies

The single skinned muscle fibre technique was used to investigate Ca2+- and Sr2+- activation properties of skeletal muscle fibres from elderly women (66-90 years). Muscle biopsies were obtained from the vastus lateralis muscle. Three populations of muscle fibres were identified according to their specific Sr2+- activation properties: slow-twitch (type I) fast-twitch (type II) and hybrid (type I/II) fibres. All three fibre types were sampled from the biopsies of 66 to 72 years old women, but the muscle biopsies of women older than 80 years yielded only slow-twitch (type I) fibres. The proportion of hybrid fibres in the vastus lateralis muscle of women of circa 70 years of age (24%) was several-fold greater than in the same muscle of adults (<10%), suggesting that muscle remodelling occurs around this age. There were no differences between the Ca2+- and Sr2+- activation properties of slow-twitch fibres from the two groups of elderly women, but there were differences compared with muscle fibres from adults with respect to sensitivity to Ca2+, steepness of the activation curves, and characteristics of the fibre-type dependent phenomenon of spontaneous force oscillations (SOMO) occurring at sub-maximal levels of activation. The maximal Ca2+ activated specific force from all the fibres collected from the seven old women use in the present study was significantly lower by 20% than in the same muscle of adults. Taken together these results show there are qualitative and quantitative changes in the activation properties of the contractile apparatus of muscle fibres from the vastus lateralis muscle of women with advancing age, and that these changes need to be considered when explaining observed changes in womens mobility with aging.

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A moderate glycemic meal before endurance exercise can enhance performance

Journal of Applied Physiology ◽

10.1152/jappl.1998.84.1.53 ◽

1998 ◽

Vol 84 (1) ◽

pp. 53-59 ◽

Cited By ~ 60

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.

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Intramyocellular lipid content is increased after exercise in nonexercising human skeletal muscle

Journal of Applied Physiology ◽

10.1152/japplphysiol.00304.2003 ◽

2003 ◽

Vol 95 (6) ◽

pp. 2328-2332 ◽

Cited By ~ 58

Author(s):

V. B. Schrauwen-Hinderling ◽

L. J. C. van Loon ◽

R. Koopman ◽

K. Nicolay ◽

W. H. M. Saris ◽

...

Keyword(s):

Endurance Exercise ◽

Biceps Brachii ◽

Vastus Lateralis ◽

Vastus Lateralis Muscle ◽

Intramyocellular Lipid ◽

Concomitant Increase ◽

Active Muscle ◽

Lateralis Muscle ◽

Before And After ◽

Plasma Ffa

Intramyocellular lipid (IMCL) content has been reported to decrease after prolonged submaximal exercise in active muscle and, therefore, seems to form an important local substrate source. Because exercise leads to a substantial increase in plasma free fatty acid (FFA) availability with a concomitant increase in FFA uptake by muscle tissue, we aimed to investigate potential differences in the net changes in IMCL content between contracting and noncontracting skeletal muscle after prolonged endurance exercise. IMCL content was quantified by magnetic resonance spectroscopy in eight trained cyclists before and after a 3-h cycling protocol (55% maximal energy output) in the exercising vastus lateralis and the nonexercising biceps brachii muscle. Blood samples were taken before and after exercise to determine plasma FFA, glycerol, and triglyceride concentrations, and substrate oxidation was measured with indirect calorimetry. Prolonged endurance exercise resulted in a 20.4 ± 2.8% ( P < 0.001) decrease in IMCL content in the vastus lateralis muscle. In contrast, we observed a substantial (37.9 ± 9.7%; P < 0.01) increase in IMCL content in the less active biceps brachii muscle. Plasma FFA and glycerol concentrations were substantially increased after exercise (from 85 ± 6 to 1,450 ± 55 and 57 ± 11 to 474 ± 54 μM, respectively; P < 0.001), whereas plasma triglyceride concentrations were decreased (from 1,498 ± 39 to 703 ± 7 μM; P < 0.001). IMCL is an important substrate source during prolonged moderate-intensity exercise and is substantially decreased in the active vastus lateralis muscle. However, prolonged endurance exercise with its concomitant increase in plasma FFA concentration results in a net increase in IMCL content in less active muscle.

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Myofibril and Mitochondrial Area Changes in Type I and II Fibers Following 10 Weeks of Resistance Training in Previously Untrained Men

Frontiers in Physiology ◽

10.3389/fphys.2021.728683 ◽

2021 ◽

Vol 12 ◽

Author(s):

Bradley A. Ruple ◽

Joshua S. Godwin ◽

Paulo H. C. Mesquita ◽

Shelby C. Osburn ◽

Casey L. Sexton ◽

...

Keyword(s):

Resistance Training ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Vastus Lateralis ◽

Thigh Muscle ◽

Vastus Lateralis Muscle ◽

Type I ◽

Cross Sectional ◽

Lateralis Muscle ◽

Actin Protein

Resistance training increases muscle fiber hypertrophy, but the morphological adaptations that occur within muscle fibers remain largely unresolved. Fifteen males with minimal training experience (24±4years, 23.9±3.1kg/m2 body mass index) performed 10weeks of conventional, full-body resistance training (2× weekly). Body composition, the radiological density of the vastus lateralis muscle using peripheral quantitative computed tomography (pQCT), and vastus lateralis muscle biopsies were obtained 1week prior to and 72h following the last training bout. Quantification of myofibril and mitochondrial areas in type I (positive for MyHC I) and II (positive for MyHC IIa/IIx) fibers was performed using immunohistochemistry (IHC) techniques. Relative myosin heavy chain and actin protein abundances per wet muscle weight as well as citrate synthase (CS) activity assays were also obtained on tissue lysates. Training increased whole-body lean mass, mid-thigh muscle cross-sectional area, mean and type II fiber cross-sectional areas (fCSA), and maximal strength values for leg press, bench press, and deadlift (p<0.05). The intracellular area occupied by myofibrils in type I or II fibers was not altered with training, suggesting a proportional expansion of myofibrils with fCSA increases. However, our histological analysis was unable to differentiate whether increases in myofibril number or girth occurred. Relative myosin heavy chain and actin protein abundances also did not change with training. IHC indicated training increased mitochondrial areas in both fiber types (p=0.018), albeit CS activity levels remained unaltered with training suggesting a discordance between these assays. Interestingly, although pQCT-derived muscle density increased with training (p=0.036), suggestive of myofibril packing, a positive association existed between training-induced changes in this metric and changes in mean fiber myofibril area (r=0.600, p=0.018). To summarize, our data imply that shorter-term resistance training promotes a proportional expansion of the area occupied by myofibrils and a disproportional expansion of the area occupied by mitochondria in type I and II fibers. Additionally, IHC and biochemical techniques should be viewed independently from one another given the lack of agreement between the variables assessed herein. Finally, the pQCT may be a viable tool to non-invasively track morphological changes (specifically myofibril density) in muscle tissue.

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The Effect of Aerobic Exercise Training on the Distribution of Succinate Dehydrogenase Activity Throughout Muscle Fibres

Canadian Journal of Applied Physiology ◽

10.1139/h98-005 ◽

1998 ◽

Vol 23 (1) ◽

pp. 74-86 ◽

Cited By ~ 17

Author(s):

Philip D. Chilibeck ◽

Gordon J. Bell ◽

Teresa Socha ◽

Tom Martin

Keyword(s):

Endurance Training ◽

Succinate Dehydrogenase ◽

Vastus Lateralis ◽

Aerobic Exercise Training ◽

Control Group ◽

Muscle Fibres ◽

Vastus Lateralis Muscle ◽

Type I ◽

Lateralis Muscle ◽

Subsarcolemmal Mitochondria

We evaluated the effect of endurance training (cycling 3 times per week for 12 weeks) on succinate dehydrogenase (SDH) activity in the subsarcolemmal (SS) and intermyofibrillar (IMF) regions of vastus lateralis muscle fibres in 7 individuals (4 females and 3 males). SDH activity of the SS region increased 9.4% and 12.8% in type I and II fibres, respectively (p < .05). SDH activity of the IMF region increased 4.7% and 6.7% in type I and II fibres, respectively (p < .05). This was less than the increase in the SS region (p < .O5). No significant changes were observed in a control group (4 females and 3 males). These data suggest that mitochondria in the SS and IMF regions of human vastus lateralis muscle fibres are sensitive to endurance training. The greater response in the SS region suggests that the metabolic requirements of SS mitochondria were stressed to a greater extent than IMF mitochondria with endurance training. Key words: subsarcolemmal mitochondria, intermyofibrillar mitochondria

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Influence of complete spinal cord injury on skeletal muscle within 6 mo of injury

Journal of Applied Physiology ◽

10.1152/jappl.1999.86.1.350 ◽

1999 ◽

Vol 86 (1) ◽

pp. 350-358 ◽

Cited By ~ 200

Author(s):

Michael J. Castro ◽

David F. Apple ◽

Robert S. Staron ◽

Gerson E. R. Campos ◽

Gary A. Dudley

Keyword(s):

Skeletal Muscle ◽

Fiber Type ◽

Vastus Lateralis ◽

Vastus Lateralis Muscle ◽

Type I ◽

Cord Injury ◽

Lateralis Muscle ◽

Type I Fibers ◽

Femoris Muscle ◽

Over Time

This study examined the influence of spinal cord injury (SCI) on affected skeletal muscle. The right vastus lateralis muscle was biopsied in 12 patients as soon as they were clinically stable (average 6 wk after SCI), and 11 and 24 wk after injury. Samples were also taken from nine able-bodied controls at two time points 18 wk apart. Surface electrical stimulation (ES) was applied to the left quadriceps femoris muscle to assess fatigue at these same time intervals. Biopsies were analyzed for fiber type percent and cross-sectional area (CSA), fiber type-specific succinic dehydrogenase (SDH) and α-glycerophosphate dehydrogenase (GPDH) activities, and myosin heavy chain percent. Controls showed no change in any variable over time. Patients showed 27–56% atrophy ( P = 0.000) of type I, IIa, and IIax+IIx fibers from 6 to 24 wk after injury, resulting in fiber CSA approximately one-third that of controls. Their fiber type specific SDH and GPDH activities increased ( P ≤ 0.001) from 32 to 90% over the 18 wk, thereby approaching or surpassing control values. The relative CSA of type I fibers and percentage of myosin heavy chain type I did not change. There was apparent conversion among type II fiber subtypes; type IIa decreased and type IIax+IIx increased ( P ≤ 0.012). Force loss during ES did not change over time for either group but was greater ( P = 0.000) for SCI patients than for controls overall (27 vs. 9%). The results indicate that vastus lateralis muscle shows marked fiber atrophy, no change in the proportion of type I fibers, and a relative independence of metabolic enzyme levels from activation during the first 24 wk after clinically complete SCI. Over this time, quadriceps femoris muscle showed moderately greater force loss during ES in patients than in controls. It is suggested that the predominant response of mixed human skeletal muscle within 6 mo of SCI is loss of contractile protein. Therapeutic interventions could take advantage of this to increase muscle mass.

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Myofibril and Mitochondrial Area Changes in Type I and II Fibers Following 10 Weeks of Resistance Training in Previously Untrained Men

10.20944/preprints202106.0349.v1 ◽

2021 ◽

Author(s):

Bradley A. Ruple ◽

Joshua S. Godwin ◽

Paulo H. C. Mesquita ◽

Shelby C. Osburn ◽

Casey L. Sexton ◽

...

Keyword(s):

Resistance Training ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Vastus Lateralis ◽

Thigh Muscle ◽

Vastus Lateralis Muscle ◽

Type I ◽

Cross Sectional ◽

Lateralis Muscle ◽

Actin Protein

Resistance training increases myofiber hypertrophy, but the morphological adaptations that occur within myofibers remain largely unresolved. Fifteen males with minimal training experience (24±4 years, 17.9±1.4 kg/m2 lean body mass index) performed 10 weeks of conventional, full-body resistance training (2x weekly). Body composition, the radiological density of the vastus lateralis muscle using peripheral quantitative computed tomography (pQCT), and vastus lateralis muscle biopsies were obtained one week prior to and 72 hours following the last training bout. Fiber typing and the quantification of myofibril and mitochondrial areas per fiber were performed using histology/immunohistochemistry (IHC) techniques. Relative myosin heavy chain and actin protein abundances per wet muscle weight as well as citrate synthase (CS) activity assays were also obtained on tissue lysates. Training increased whole-body lean mass, mid-thigh muscle cross-sectional area, various strength metrics, and mean and type II fiber cross sectional areas (fCSA) (p<0.05). Myofibril areas in type I or II fibers were not altered with training, suggesting a proportional expansion with fCSA increases. Relative myosin heavy chain and actin protein abundances also did not change with training. IHC indicated training increased mitochondrial areas in both fiber types (p=0.018). However, CS activity levels remained unaltered with training. Interestingly, although pQCT-derived muscle density increased with training (p=0.036), suggestive of myofibril packing, a positive association existed between training-induced changes in this metric and changes in type I+II myofibril areas (r=0.600, p=0.018). Shorter-term resistance training seemingly involves a proportional expansion of myofibrils and an accelerated expansion of mitochondria in type I and II fibers. Additionally, histological and biochemical techniques should be viewed independently from one another given the lack of agreement between the variables assessed herein. Finally, the pQCT may be a viable tool to non-invasively track morphological changes in muscle tissue.

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Glycogen Depletion of Human Skeletal Muscle Fibers in Response to High-Frequency Electrical Stimulation

Canadian Journal of Applied Physiology ◽

10.1139/h03-031 ◽

2003 ◽

Vol 28 (3) ◽

pp. 424-433 ◽

Cited By ~ 2

Author(s):

Michel J. Johnson ◽

Gilles Lortie ◽

Jean-Aimé Simoneau ◽

Marcel R. Boulay

Keyword(s):

Electrical Stimulation ◽

High Frequency ◽

Human Skeletal Muscle ◽

Glycogen Content ◽

Isometric Force ◽

Vastus Lateralis ◽

Muscle Fibres ◽

Vastus Lateralis Muscle ◽

Type I ◽

Lateralis Muscle

The purpose of the present study was to evaluate the pattern of change in muscular glycogen content in response to high-frequency electrical stimulation (HFES). Muscle biopsies were taken from the vastus lateralis muscle of 7 healthy young men before, 15 min after, and 30 min after electrical stimulation delivered at a 50-Hz frequency (15 s on, 45 s off) at an intensity of 100 mA. The glycogen content of type I, IIA, and IIB muscle fibres was evaluated using microphotometry of periodic acid Schiff (PAS) stained fibres. After 15 min of electrical stimulation, the glycogen content in type I, IIA, and IIB muscle fibres significantly decreased from 113 ± 10 (mean ± SE) to 103 ± 10 (p ≤ 0.05), 129 ± 9 to 102 ± 12 (p ≤ 0.01), and 118 ± 8 to 90 ± 13 (p ≤ 0.01) arbitrary relative units, respectively. No further decrement in glycogen content was observed in all three fibre types following an additional 15 min of HFES. In addition, isometric force decreased by approximately 50%, from 125.9 ± 20.0 N to 64.2 ± 7.7 N (p ≤ 0.01), during the first 15 contractions. No further decrease in isometric force was observed following an additional 15 contractions of HFES. These results reveal that significant reductions in isometric force of knee extensor muscles and glycogen content of all human skeletal muscle fibre types in vastus lateralis muscle are observable after 15 min of neuromuscular high-frequency transcutaneous electrical stimulation. Key words: energy metabolism, isometric strength

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Ayurvedic management of Myositis Ossificans of Vastus Lateralis Muscle (Urusthamba) - A Case Study

Journal of Ayurveda and Integrated Medical Sciences (JAIMS) ◽

10.21760/jaims.v2i1.7523 ◽

2017 ◽

Vol 2 (1) ◽

Author(s):

Vishnu Mohan ◽

Gopikrishna BJ ◽

Avnish Pathak ◽

Mahesh Kumar ES ◽

Duradundi G

Keyword(s):

Heterotopic Ossification ◽

Myositis Ossificans ◽

Vastus Lateralis ◽

Treatment Protocol ◽

Vastus Lateralis Muscle ◽

Satisfactory Treatment ◽

Lateralis Muscle ◽

Ayurvedic Treatment

Myositis ossificansis characterized by heterotopic ossification (calcification) of muscle of various etiologies. It is most commonly affected in the quadriceps of the thighs. There are many tools available for diagnosis of Myositis ossificans, but lack of satisfactory treatment. So the development of a treatment protocol for Myositis ossificans is the need of today`s era. In Ayurveda, the same can be understood as Urusthamba. The present paper discusses a case of Myositis ossificans of right vastus lateralis muscle and its Ayurvedic treatment.

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