scholarly journals Skeletal muscle size, function, and adiposity with lifelong aerobic exercise

2020 ◽  
Vol 128 (2) ◽  
pp. 368-378 ◽  
Author(s):  
Toby L. Chambers ◽  
Timothy R. Burnett ◽  
Ulrika Raue ◽  
Gary A. Lee ◽  
W. Holmes Finch ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Aerobic Exercise ◽  
Life Span ◽  
Exercise Intensity ◽  
Lower Leg ◽  
Muscle Size ◽  
Training Intensity ◽  
Size Function ◽  
Leg Muscle

We examined the influence of lifelong aerobic exercise on skeletal muscle size, function, and adiposity. Young exercisers [YE; n = 20, 10 women (W), 25 ± 1 yr], lifelong exercisers (LLE; n = 28, 7 W, 74 ± 2 yr), and old healthy nonexercisers (OH; n = 20, 10 W, 75 ± 1 yr) were studied. On average, LLE exercised 5 days/wk for 7 h/wk over the past 52 ± 1 yr. The LLE men were subdivided by exercise intensity [Performance (LLE-P), n = 14; Fitness (LLE-F), n = 7]. Upper and lower leg muscle size and adiposity [intermuscular adipose tissue (IMAT)] were determined via MRI, and quadriceps isotonic and isometric function was assessed. For the quadriceps, aging decreased muscle size, isotonic and isometric strength, contraction velocity (men only), and power ( P < 0.05). In women, LLE did not influence muscle size or function. In men, LLE attenuated the decline in muscle size and isometric strength by ~50% ( P < 0.05). LLE did not influence other aspects of muscle function, nor did training intensity influence muscle size or function. For the triceps surae, aging decreased muscle size only in the women, whereas LLE (both sexes) and training intensity (LLE men) did not influence muscle size. In both sexes, aging increased thigh and calf IMAT by ~130% ( P < 0.05), whereas LLE attenuated the thigh increase by ~50% ( P < 0.05). In the LLE men, higher training intensity decreased thigh and calf IMAT by ~30% ( P < 0.05). In summary, aging and lifelong aerobic exercise influenced muscle size, function, and adipose tissue infiltration in a sex- and muscle-specific fashion. Higher training intensity throughout the life span provided greater protection against adipose tissue infiltration into muscle. NEW & NOTEWORTHY This is the first study to examine skeletal muscle size, function, and adiposity in women and men in their eighth decade of life that have engaged in lifelong aerobic exercise. The findings reveal sex and upper and lower leg muscle group-specific benefits related to skeletal muscle size, function, and adiposity and that exercise intensity influences intermuscular adiposity. This emerging cohort will further our understanding of the health implications of maintaining exercise throughout the life span.

8 Week Exercise Protocol and Minimalist Shoes Walking Effect on Lower Leg Muscle Size

2016 ◽  
Vol 48 ◽  
pp. 8
Author(s):  
Aaron W. Johnson ◽  
Tiffany D. deVries ◽  
Shaun Brewer ◽  
Andrew Rich ◽  
Joseph W. Myrer ◽  
...  
Keyword(s):  
Lower Leg ◽  
Muscle Size ◽  
Exercise Protocol ◽  
Leg Muscle

scholarly journals Insulin-resistant subjects have normal angiogenic response to aerobic exercise training in skeletal muscle, but not in adipose tissue

2015 ◽  
Vol 3 (6) ◽  
pp. e12415 ◽  
Author(s):  
R. Grace Walton ◽  
Brian S. Finlin ◽  
Jyothi Mula ◽  
Douglas E. Long ◽  
Beibei Zhu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Exercise Training ◽  
Aerobic Exercise ◽  
Aerobic Exercise Training ◽  
Angiogenic Response ◽  
Insulin Resistant

Effect of voluntary exercise on peripheral tissue glucocorticoid receptor content and the expression and activity of 11β-HSD1 in the Syrian hamster

2006 ◽  
Vol 100 (5) ◽  
pp. 1483-1488 ◽  
Author(s):  
Agnes E. Coutinho ◽  
Jonathan E. Campbell ◽  
Sergiu Fediuc ◽  
Michael C. Riddell
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Metabolic Syndrome ◽  
Enzyme Activity ◽  
Adipose Tissue ◽  
Protein Expression ◽  
Aerobic Exercise ◽  
Visceral Adipose Tissue ◽  
The Metabolic Syndrome ◽  
Visceral Adipose

Recent findings indicate that elevated levels of glucocorticoids (GC), governed by the expression of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and GC receptors (GR), in visceral adipose tissue and skeletal muscle lead to increased insulin resistance and the metabolic syndrome. Paradoxically, evidence indicates that aerobic exercise attenuates the development of the metabolic syndrome even though it stimulates acute increases in circulating GC levels. To investigate the hypothesis that training alters peripheral GC action to maintain insulin sensitivity, young male hamsters were randomly divided into sedentary (S) and trained (T) groups ( n = 8 in each). The T group had 24-h access to running wheels over 4 wk of study. In muscle, T hamsters had lower 11β-HSD1 protein expression (19.2 ± 1.40 vs. 22.2 ± 0.96 optical density, P < 0.05), similar 11β-HSD1 enzyme activity (0.9 ± 0.27% vs. 1.1 ± 0.26), and lower GR protein expression (9.7 ± 1.86 vs. 15.1 ± 1.78 optical density, P < 0.01) than S hamsters. In liver, 11β-HSD1 protein expression tended to be lower in T compared with S (19.2 ± 0.56 vs. 21.4 ± 1.05, P = 0.07), whereas both enzyme activity and GR protein expression were similar. In contrast, visceral adipose tissue contained ∼2.7-fold higher 11β-HSD1 enzyme activity in T compared with S (12.9 ± 3.3 vs. 4.8 ± 1.5% conversion, P < 0.05) but was considerably smaller in mass (0.24 ± 0.02 vs. 0.71 ± 0.06 g). Thus the intracellular adaptation of GC regulators to exercise is tissue specific, resulting in decreases in GC action in skeletal muscle and increases in GC action in visceral fat. These adaptations may have important implications in explaining the protective effects of aerobic exercise on insulin resistance and other symptoms of the metabolic syndrome.

scholarly journals A 12-week aerobic exercise intervention results in improved metabolic function and lower adipose tissue and ectopic fat in high-fat diet fed rats

2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Venkatesh Gopalan ◽  
Jadegoud Yaligar ◽  
Navin Michael ◽  
Kavita Kaur ◽  
Rengaraj Anantharaj ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Aerobic Exercise ◽  
High Fat Diet ◽  
Inflammatory Markers ◽  
Metabolic Profile ◽  
Ectopic Fat ◽  
High Fat ◽  
Intervention Measures ◽  
Fat Pads

Abstract Investigations of long-term exercise interventions in humans to reverse obesity is expensive and is hampered by poor compliance and confounders. In the present study, we investigated intrahepatic and muscle fat, visceral and subcutaneous fat pads, plasma metabolic profile and skeletal muscle inflammatory markers in response to 12-week aerobic exercise in an obese rodent model. Six-week-old male Wistar rats (n=20) were randomized to chow-fed control (Control, n=5), sedentary high-fat diet (HFD, n=5), chow-fed exercise (Exercise, n=5) and HFD-fed exercise (HFD+Exercise, n=5) groups. The exercise groups were subjected to 12 weeks of motorized treadmill running at a speed of 18 m/min for 30 min/day. Differences in post-intervention measures were assessed by analysis of covariance (ANCOVA), adjusted for baseline bodyweight and pre-intervention measures, where available. Post-hoc analyses were performed with Bonferroni correction. Plasma metabolic profile was worsened and fat pads, ectopic fat in muscle and liver and inflammatory markers in skeletal muscle were elevated in sedentary HFD-fed animals relative to chow-fed controls. HFD+Exercise animals had significantly lower leptin (P=0.0004), triglycerides (P=0.007), homeostatic model assessment of insulin resistance (HOMA-IR; P=0.065), intramyocellular lipids (IMCLs; P=0.003), intrahepatic lipids (IHLs; P&lt;0.0001), body fat% (P=0.001), subcutaneous adipose tissue (SAT; P&lt;0.0001), visceral adipose (P&lt;0.0001) and total fat mass (P&lt;0.0001), relative to sedentary HFD-fed animals, despite only modestly lower bodyweight. Messenger RNA (mRNA) expression of inflammatory markers Interleukin 6 (IL6) and Tumor necrosis factor α (TNFα) were also reduced with aerobic exercise in skeletal muscle. Our results suggest that 12 weeks of aerobic exercise training is effective in improving metabolic health, fat depots, ectopic fat and inflammation even against a high-fat dietary background.

scholarly journals Aerobic exercise training induces skeletal muscle hypertrophy and age-dependent adaptations in myofiber function in young and older men

2012 ◽  
Vol 113 (9) ◽  
pp. 1495-1504 ◽  
Author(s):  
Matthew P. Harber ◽  
Adam R. Konopka ◽  
Miranda K. Undem ◽  
James M. Hinkley ◽  
Kiril Minchev ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Aerobic Exercise ◽  
Peak Power ◽  
Muscle Protein ◽  
Peak Force ◽  
Aerobic Exercise Training ◽  
Muscle Size ◽  
Mhc I ◽  
Age Dependent ◽  
Mhc Iia

To examine potential age-specific adaptations in skeletal muscle size and myofiber contractile physiology in response to aerobic exercise, seven young (YM; 20 ± 1 yr) and six older men (OM; 74 ± 3 yr) performed 12 wk of cycle ergometer training. Muscle biopsies were obtained from the vastus lateralis to determine size and contractile properties of isolated slow [myosin heavy chain (MHC) I] and fast (MHC IIa) myofibers, MHC composition, and muscle protein concentration. Aerobic capacity was higher ( P < 0.05) after training in both YM (16 ± 2%) and OM (13 ± 3%). Quadriceps muscle volume, determined via MRI, was 5 ± 1 and 6 ± 1% greater ( P < 0.05) after training for YM and OM, respectively, which was associated with an increase in MHC I myofiber cross-sectional area (CSA), independent of age. MHC I peak power was higher ( P < 0.05) after training for both YM and OM, while MHC IIa peak power was increased ( P < 0.05) with training in OM only. MHC I and MHC IIa myofiber peak and normalized (peak force/CSA) force were preserved with training in OM, while MHC I peak force/CSA and MHC IIa peak force were lower ( P < 0.05) after training in YM. The age-dependent adaptations in myofiber function were not due to changes in protein content, as total muscle protein and myofibrillar protein concentration were unchanged ( P > 0.05) with training. Training reduced ( P < 0.05) the proportion of MHC IIx isoform, independent of age, whereas no other changes in MHC composition were observed. These data suggest relative improvements in muscle size and aerobic capacity are similar between YM and OM, while adaptations in myofiber contractile function showed a general improvement in OM. Training-related increases in MHC I and MHC IIa peak power reveal that skeletal muscle of OM is responsive to aerobic exercise training and further support the use of aerobic exercise for improving cardiovascular and skeletal muscle health in older individuals.

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