scholarly journals Interval and Continuous Exercise Training Produce Similar Increases in Skeletal Muscle and Left Ventricle Microvascular Density in Rats

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Flávio Pereira ◽  
Roger de Moraes ◽  
Eduardo Tibiriçá ◽  
Antonio C. L. Nóbrega
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Left Ventricle ◽  
Body Weight Gain ◽  
Interval Training ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Constant Load ◽  
Continuous Exercise ◽  
Muscle Ct

Interval training (IT), consisting of alternated periods of high and low intensity exercise, has been proposed as a strategy to induce more marked biological adaptations than continuous exercise training (CT). The purpose of this study was to assess the effects of IT and CT with equivalent total energy expenditure on capillary skeletal and cardiac muscles in rats. Wistar rats ran on a treadmill for 30 min per day with no slope (0%), 4 times/week for 13 weeks. CT has constant load of 70% max; IT has cycles of 90% max for 1 min followed by 1 min at 50% max. CT and IT increased endurance and muscle oxidative capacity and attenuated body weight gain to a similar extent (P>0.05). In addition, CT and IT similarly increased functional capillary density of skeletal muscle (CT:30.6±11.7%; IT:28.7±11.9%) and the capillary-to-fiber ratio in skeletal muscle (CT:28.7±14.4%; IT:40.1±17.2%) and in the left ventricle (CT:57.3±53.1%; IT:54.3±40.5%). In conclusion, at equivalent total work volumes, interval exercise training induced similar functional and structural alterations in the microcirculation of skeletal muscle and myocardium in healthy rats compared to continuous exercise training.

scholarly journals Acute upregulation of PGC-1α mRNA correlates with training-induced increases in SDH activity in human skeletal muscle

2017 ◽  
Vol 42 (6) ◽  
pp. 656-666 ◽  
Author(s):  
Jacob T. Bonafiglia ◽  
Brittany A. Edgett ◽  
Brittany L. Baechler ◽  
Matthew W. Nelms ◽  
Craig A. Simpson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Human Skeletal Muscle ◽  
Interval Training ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Peak Oxygen Uptake ◽  
Fibre Type Composition ◽  
Type Composition ◽  
Acute Responses

The purpose of the present study was to determine if acute responses in PGC-1α, VEGFA, SDHA, and GPD1–2 mRNA expression predict their associated chronic skeletal muscle molecular (SDH–GPD activity and substrate storage) and morphological (fibre-type composition and capillary density) adaptations following training. Skeletal muscle biopsies were collected from 14 recreationally active men (age: 22.0 ± 2.4 years) before (PRE) and 3 h after (3HR) the completion of an acute bout of sprint interval training (SIT) (eight 20-s intervals at ∼170% peak oxygen uptake work rate separated by 10 s of recovery). Participants then completed 6 weeks of SIT 4 times per week with additional biopsies after 2 (MID) and 6 (POST) weeks of training. Acute increases in PGC-1α mRNA strongly predicted increases in SDH activity (a marker of oxidative capacity) from PRE and MID to POST (PRE–POST: r = 0.81, r2 = 0.65, p < 0.01; MID–POST: r = 0.79, r2 = 0.62, p < 0.01) and glycogen content from MID to POST (r = 0.60, r2 = 0.36, p < 0.05). No other significant relationships were found between acute responses in PGC-1α, VEGFA, SDHA, and GPD1–2 mRNA expression and chronic adaptations to training. These results suggest that acute upregulation of PGC-1α mRNA relates to the magnitude of subsequent training-induced increases in oxidative capacity, but not other molecular and morphological chronic skeletal muscle adaptations. Additionally, acute mRNA responses in PGC-1α correlated with VEGFA, but not SDHA, suggesting a coordinated upregulation between PGC-1α and only some of its proposed targets in human skeletal muscle.

scholarly journals Exercise-induced alterations in intramyocellular lipids and insulin resistance: the athlete's paradox revisited

2008 ◽  
Vol 294 (5) ◽  
pp. E882-E888 ◽  
Author(s):  
John J. Dubé ◽  
Francesca Amati ◽  
Maja Stefanovic-Racic ◽  
Frederico G. S. Toledo ◽  
Sarah E. Sauers ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Exercise Training ◽  
Glycogen Content ◽  
Fiber Type ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Type I ◽  
Euglycemic Hyperinsulinemic Clamp ◽  
Athlete’S Paradox

We previously reported an “athlete's paradox” in which endurance-trained athletes, who possess a high oxidative capacity and enhanced insulin sensitivity, also have higher intramyocellular lipid (IMCL) content. The purpose of this study was to determine whether moderate exercise training would increase IMCL, oxidative capacity of muscle, and insulin sensitivity in previously sedentary overweight to obese, insulin-resistant, older subjects. Twenty-five older (66.4 ± 0.8 yr) obese (BMI = 30.3 ± 0.7 kg/m2) men ( n = 9) and women ( n = 16) completed a 16-wk moderate but progressive exercise training program. Body weight and fat mass modestly but significantly ( P < 0.01) decreased. Insulin sensitivity, measured using the euglycemic hyperinsulinemic clamp, was increased (21%, P = 0.02), with modest improvements (7%, P = 0.04) in aerobic fitness (V̇o2peak). Histochemical analyses of IMCL (Oil Red O staining), oxidative capacity [succinate dehydrogenase activity (SDH)], glycogen content, capillary density, and fiber type were performed on skeletal muscle biopsies. Exercise training increased IMCL by 21%. In contrast, diacylglycerol and ceramide, measured by mass spectroscopy, were decreased ( n = 13; −29% and −24%, respectively, P < 0.05) with exercise training. SDH (19%), glycogen content (15%), capillary density (7%), and the percentage of type I slow oxidative fibers (from 50.8 to 55.7%), all P ≤ 0.05, were increased after exercise. In summary, these results extend the athlete's paradox by demonstrating that chronic exercise in overweight to obese older adults improves insulin sensitivity in conjunction with favorable alterations in lipid partitioning and an enhanced oxidative capacity within muscle. Therefore, several key deleterious effects of aging and/or obesity on the metabolic profile of skeletal muscle can be reversed with only moderate increases in physical activity.

Combined effects of a ketogenic diet and exercise training alter mitochondrial and peroxisomal substrate oxidative capacity in skeletal muscle

2021 ◽  
Author(s):  
Tai-Yu Huang ◽  
Melissa A. Linden ◽  
Scott E. Fuller ◽  
Felicia R Goldsmith ◽  
Jacob Simon ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Weight ◽  
Exercise Training ◽  
Fat Mass ◽  
Mitochondrial Fission ◽  
Critical Role ◽  
Oxidative Capacity ◽  
Low Fat Diet ◽  
Ketogenic Diets ◽  
Diet And Exercise

Ketogenic diets (KD) are reported to improve body weight, fat mass, and exercise performance in humans. Unfortunately, most rodent studies have used a low-protein KD, which does not recapitulate diets used by humans. Since skeletal muscle plays a critical role in responding to macronutrient perturbations induced by diet and exercise, the purpose of this study was to test if a normal-protein KD (NPKD) impacts shifts in skeletal muscle substrate oxidative capacity in response to exercise training (ExTr). A high fat, carbohydrate-deficient NPKD (16.1% protein, 83.9% fat, 0% carbohydrate) was given to C57BL/6J male mice for 6 weeks, while controls received a low fat diet with similar protein (15.9% protein, 11.9% fat, 72.2% carbohydrate). On week four of the diet, mice began treadmill training 5 days/week, 60 min/day for 3 weeks. NPKD-fed mice increased body weight and fat mass, while ExTr negated a continued rise in adiposity. ExTr increased intramuscular glycogen, while the NPKD increased intramuscular triglycerides. Neither the NPKD nor ExTr alone altered mitochondrial content; however, in combination, the NPKD-ExTr group showed increases in PGC-1α, as well as markers of mitochondrial fission and fusion. Pyruvate oxidative capacity was unchanged by either intervention, while ExTr increased leucine oxidation in NPKD-fed mice. Lipid metabolism pathways had the most notable changes as the NPKD and ExTr interventions both enhanced mitochondrial and peroxisomal lipid oxidation and many adaptations were additive or synergistic. Overall these results suggest a combination of a NPKD and ExTr induces additive and/or synergistic adaptations in skeletal muscle oxidative capacity.

Skeletal muscle biochemical adaptations to exercise training in miniature swine

1997 ◽  
Vol 82 (6) ◽  
pp. 1862-1868 ◽  
Author(s):  
Richard M. McAllister ◽  
Brian L. Reiter ◽  
John F. Amann ◽  
M. Harold Laughlin
Keyword(s):  
Skeletal Muscle ◽  
Antioxidant Enzymes ◽  
Lactate Dehydrogenase ◽  
Exercise Training ◽  
Endurance Exercise ◽  
Oxidative Capacity ◽  
Treadmill Running ◽  
Miniature Swine ◽  
Endurance Exercise Training ◽  
Hydroxyacyl Coa Dehydrogenase

McAllister, Richard M., Brian L. Reiter, John F. Amann, and M. Harold Laughlin. Skeletal muscle biochemical adaptations to exercise training in miniature swine. J. Appl. Physiol. 82(6): 1862–1868, 1997.—The primary purpose of this study was to test the hypothesis that endurance exercise training induces increased oxidative capacity in porcine skeletal muscle. To test this hypothesis, female miniature swine were either trained by treadmill running 5 days/wk over 16–20 wk (Trn; n = 35) or pen confined (Sed; n = 33). Myocardial hypertrophy, lower heart rates during submaximal stages of a maximal treadmill running test, and increased running time to exhaustion during that test were indicative of training efficacy. A variety of skeletal muscles were sampled and subsequently assayed for the enzymes citrate synthase (CS), 3-hydroxyacyl-CoA dehydrogenase, and lactate dehydrogenase and for antioxidant enzymes. Fiber type composition of a representative muscle was also determined histochemically. The largest increase in CS activity (62%) was found in the gluteus maximus muscle (Sed, 14.7 ± 1.1 μmol ⋅ min−1 ⋅ g−1; Trn, 23.9 ± 1.0; P < 0.0005). Muscles exhibiting increased CS activity, however, were located primarily in the forelimb; ankle and knee extensor and respiratory muscles were unchanged with training. Only two muscles exhibited higher 3-hydroxyacyl-CoA dehydrogenase activity in Trn compared with Sed. Lactate dehydrogenase activity was unchanged with training, as were activities of antioxidant enzymes. Histochemical analysis of the triceps brachii muscle (long head) revealed lower type IIB fiber numbers in Trn (Sed, 42 ± 6%; Trn, 10 ± 4; P < 0.01) and greater type IID/X fiber numbers (Sed, 11 ± 2; Trn, 22 ± 3; P < 0.025). These findings indicate that porcine skeletal muscle adapts to endurance exercise training in a manner similar to muscle of humans and other animal models, with increased oxidative capacity. Specific muscles exhibiting these adaptations, however, differ between the miniature swine and other species.

Exercise-induced cellular alterations in the diaphragm

1992 ◽  
Vol 263 (5) ◽  
pp. R1093-R1098 ◽  
Author(s):  
S. K. Powers ◽  
D. Criswell ◽  
F. K. Lieu ◽  
S. Dodd ◽  
H. Silverman
Keyword(s):  
Exercise Training ◽  
Endurance Training ◽  
Fiber Type ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Control Group ◽  
Type I ◽  
Fiber Types ◽  
Image Analysis System ◽  
Cross Sectional

Limited data exist concerning the effects of exercise training on cellular oxidative capacity in the diaphragm of senescent animals. In this study we examined the changes in cellular oxidative capacity, muscle cell cross-sectional area (CSA), and capillarity within the costal diaphragm of senescent animals after a 10-wk endurance-training program. Twelve 24-mo-old female Fischer 344 rats were divided into either a sedentary control group (n = 6) or exercise training group (n = 6). The trained animals exercised on a motor-driven treadmill (60 min/day, 5 days/wk) at a work rate equal to approximately 55-65% VO2max. Capillaries were identified histologically and fiber types determined using adenosinetriphosphatase (ATPase) histochemistry. Succinate dehydrogenase (SDH) activity and CSA in individual fibers were measured using a computerized image analysis system. Exercise training did not increase (P > 0.05) the capillary-to-fiber ratio for any fiber type. However, training significantly decreased CSA (P < 0.05) and increased capillary density (capillary number/CSA) (P < 0.05) in type I, type IIa, and type IIb fibers. Furthermore, exercise training resulted in small but significant increase in SDH activity (P < 0.05) in type I and IIa fibers, whereas training did not alter SDH activity (P > 0.05) in type IIb fibers. These data demonstrate that endurance training in senescent animals results in small relative improvements in both oxidative capacity and capillary density in costal diaphragmatic type I and IIa muscle fibers. The increase in both capillary density and fiber SDH activity was largely due to a reduction in fiber CSA.

Impact of exercise training on insulin sensitivity, physical fitness, and muscle oxidative capacity in first-degree relatives of type 2 diabetic patients

2006 ◽  
Vol 290 (5) ◽  
pp. E998-E1005 ◽  
Author(s):  
Torben Østergård ◽  
Jesper L. Andersen ◽  
Birgit Nyholm ◽  
Sten Lund ◽  
K.Sreekumaran Nair ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Exercise Training ◽  
Oxidative Capacity ◽  
Diabetic Patients ◽  
Type 2 Diabetic Patients ◽  
Muscle Oxidative Capacity ◽  
First Degree Relatives ◽  
Type 2 Diabetic

First-degree relatives of type 2 diabetic patients (offspring) are often characterized by insulin resistance and reduced physical fitness (V̇o2 max). We determined the response of healthy first-degree relatives to a standardized 10-wk exercise program compared with an age-, sex-, and body mass index-matched control group. Improvements in V̇o2 max(14.1 ± 11.3 and 16.1 ± 14.2%; both P < 0.001) and insulin sensitivity (0.6 ± 1.4 and 1.0 ± 2.1 mg·kg−1·min−1; both P < 0.05) were comparable in offspring and control subjects. However, V̇o2 maxand insulin sensitivity in offspring were not related at baseline as in the controls ( r = 0.009, P = 0.96 vs. r = 0.67, P = 0.002). Likewise, in offspring, exercise-induced changes in V̇o2 maxdid not correlate with changes in insulin sensitivity as opposed to controls ( r = 0.06, P = 0.76 vs. r = 0.57, P = 0.01). Skeletal muscle oxidative capacity tended to be lower in offspring at baseline but improved equally in both offspring and controls in response to exercise training (Δcitrate synthase enzyme activity 26 vs. 20%, and Δcyclooxygenase enzyme activity 25 vs. 23%. Skeletal muscle fiber morphology and capillary density were comparable between groups at baseline and did not change significantly with exercise training. In conclusion, this study shows that first-degree relatives of type 2 diabetic patients respond normally to endurance exercise in terms of changes in V̇o2 maxand insulin sensitivity. However, the lack of a correlation between the V̇o2 maxand insulin sensitivity in the first-degree relatives of type 2 diabetic patients indicates that skeletal muscle adaptations are dissociated from the improvement in V̇o2 max. This could indicate that, in first-degree relatives, improvement of insulin sensitivity is dissociated from muscle mitochondrial functions.

scholarly journals Endurance Exercise Training Up-Regulates Lipolytic Proteins and Reduces Triglyceride Content in Skeletal Muscle of Obese Subjects

2013 ◽  
Vol 98 (12) ◽  
pp. 4863-4871 ◽  
Author(s):  
Katie Louche ◽  
Pierre-Marie Badin ◽  
Emilie Montastier ◽  
Claire Laurens ◽  
Virginie Bourlier ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Protein Expression ◽  
Endurance Exercise ◽  
Oxidative Capacity ◽  
Metabolic Effects ◽  
Gene Identification ◽  
Mrna Levels ◽  
Endurance Exercise Training ◽  
Obese Subjects

Context: Skeletal muscle lipase and intramyocellular triglyceride (IMTG) play a role in obesity-related metabolic disorders. Objectives: The aim of the present study was to investigate the impact of 8 weeks of endurance exercise training on IMTG content and lipolytic proteins in obese male subjects. Design and Volunteers: Ten obese subjects completed an 8-week supervised endurance exercise training intervention in which vastus lateralis muscle biopsy samples were collected before and after training. Main Outcome Measures: Clinical characteristics and ex vivo substrate oxidation rates were measured pre- and posttraining. Skeletal muscle lipid content and lipolytic protein expression were also investigated. Results: Our data show that exercise training reduced IMTG content by 42% (P &lt; .01) and increased skeletal muscle oxidative capacity, whereas no change in total diacylglycerol content and glucose oxidation was found. Exercise training up-regulated adipose triglyceride lipase, perilipin (PLIN) 3 protein, and PLIN5 protein contents in skeletal muscle despite no change in mRNA levels. Training also increased hormone sensitive–lipase Ser660 phosphorylation. No significant changes in comparative gene identification 58, G0/G1 switch gene 2, and PLIN2 protein and mRNA levels were observed in response to training. Interestingly, we noted a strong relationship between skeletal muscle comparative gene identification 58 and mitochondrial respiratory chain complex I protein contents at baseline (r = 0.87, P &lt; .0001). Conclusions: Endurance exercise training coordinately up-regulates fat oxidative capacity and lipolytic protein expression in skeletal muscle of obese subjects. This physiological adaptation probably favors fat oxidation and may alleviate the lipotoxic lipid pressure in skeletal muscle. Enhancement of IMTG turnover may be required for the beneficial metabolic effects of exercise in obesity.

Contribution of central and peripheral adaptations to changes in maximal oxygen uptake following 4 weeks of sprint interval training

2018 ◽  
Vol 43 (10) ◽  
pp. 1059-1068 ◽  
Author(s):  
James P. Raleigh ◽  
Matthew D. Giles ◽  
Hashim Islam ◽  
Matthew Nelms ◽  
Robert F. Bentley ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Citrate Synthase ◽  
Interval Training ◽  
Maximal Activity ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Sprint Interval Training ◽  
Peripheral Arterial

The current study examined the contribution of central and peripheral adaptations to changes in maximal oxygen uptake (V̇O2max) following sprint interval training (SIT). Twenty-three males completed 4 weekly SIT sessions (8 × 20-s cycling bouts at ∼170% of work rate at V̇O2max, 10-s recovery) for 4 weeks. Following completion of training, the relationship between changes in V̇O2max and changes in central (cardiac output) and peripheral (arterial–mixed venous oxygen difference (a-vO2diff), muscle capillary density, oxidative capacity, fibre-type distribution) adaptations was determined in all participants using correlation analysis. Participants were then divided into tertiles on the basis of the magnitude of their individual V̇O2max responses, and differences in central and peripheral adaptations were examined in the top (HI; ∼10 mL·kg−1·min−1 increase in V̇O2max, p < 0.05) and bottom (LO; no change in V̇O2max, p > 0.05) tertiles (n = 8 each). Training had no impact on maximal cardiac output, and no differences were observed between the LO group and the HI group (p > 0.05). The a-vO2diff increased in the HI group only (p < 0.05) and correlated significantly (r = 0.71, p < 0.01) with changes in V̇O2max across all participants. Muscle capillary density (p < 0.02) and β-hydroxyacyl-CoA dehydrogenase maximal activity (p < 0.05) increased in both groups, with no between-group differences (p > 0.05). Citrate synthase maximal activity (p < 0.01) and type IIA fibre composition (p < 0.05) increased in the LO group only. Collectively, although the heterogeneity in the observed V̇O2max response following 4 weeks of SIT appears to be attributable to individual differences in systemic vascular and/or muscular adaptations, the markers examined in the current study were unable to explain the divergent V̇O2max responses in the LO and HI groups.

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