Collagen content in the vastus lateralis and the soleus muscle following a 90-day bed rest period with or without resistance exercises

The interplay between chronic constraint and advanced aging on blood flow, shear-rate, vascular function, nitric oxide (NO)-bioavailability, microcirculation, and vascular inflammation factors is still a matter of debate. Ninety-eight individuals (Young, n = 28, 23 ± 3 yrs; Old, n = 36, 85 ± 7 yrs; Bedridden, n = 34, 88 ± 6 yrs) were included in the study. The bedridden group included old individuals chronically confined to bed (3.8 ± 2.3 yrs). A blood sample was collected and analyzed for plasma nitrate, and vascular inflammatory markers. Hyperemic response (∆peak) during the single passive leg movement (sPLM) test was used to measure vascular function. Skeletal muscle total hemoglobin was measured at the vastus lateralis during the sPLM test, by means of near infrared spectroscopy (NIRS). Bedridden subjects revealed a depletion of plasma nitrates compared with Old (−23.8%) and Young (−31.1%). Blood flow was lower in the Bedridden in comparison to Old (−20.1%) and Young (−31.7%). Bedridden presented lower sPLM ∆peak compared Old (−72.5%) and the Young (−83.3%). ∆peak of NIRS total hemoglobin was lower in the Bedridden compared to that in the Young (−133%). All vascular inflammatory markers except IL-6 were significantly worse in the Bedridden compared to Old and Young. No differences were found between the Old and Young in inflammatory markers. Results of this study confirm that chronic physical constraint induces an exacerbation of vascular disfunction and differential regulation of vascular-related inflammatory markers. The mechanisms involved in these negative adaptations seems to be associated with endothelial dysfunction and consequent diminished NO-bioavailability likely caused by the reduced shear-rate consequential to long-term reduction of physical activity.

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Quantitative determination of Ca2+-dependent Mg2+-ATPase from sarcoplasmic reticulum in muscle biopsies

Biochemical Journal ◽

10.1042/bj2600443 ◽

1989 ◽

Vol 260 (2) ◽

pp. 443-448 ◽

Cited By ~ 46

Author(s):

M E Everts ◽

J P Andersen ◽

T Clausen ◽

O Hansen

Keyword(s):

Sarcoplasmic Reticulum ◽

Soleus Muscle ◽

Human Subjects ◽

Vastus Lateralis ◽

Total Concentration ◽

Vastus Lateralis Muscle ◽

Lateralis Muscle ◽

32P Incorporation ◽

Muscle Biopsies

The possibility of quantifying the total concentration of Ca2+-dependent Mg2+-ATPase of sarcoplasmic reticulum was investigated by measurement of the Ca2+-dependent steady-state phosphorylation from [gamma-32P]ATP and the Ca2+-dependent 3-O-methylfluorescein phosphatase (3-O-MFPase) activity in crude muscle homogenates. The Ca2+-dependent phosphorylation at 0 degree C (mean +/- S.E.) was 40.0 +/- 2.5 (n = 6) and 6.2 +/- 0.7 (n = 4) nmol/g wet wt. in rat extensor digitorum longus (EDL) and soleus muscle, respectively (P less than 0.001). The Ca2+-dependent 3-O-MFPase activity at 37 degrees C was 1424 +/- 238 (n = 6) and 335 +/- 56 (n = 4) nmol/min per g wet wt. in rat EDL and soleus muscle, respectively (P less than 0.01). The molecular activity calculated from these measurements amounted to 35 +/- 5 min-1 (n = 6) and 55 +/- 10 min-1 (n = 4) for EDL and soleus muscle respectively. These values were not different from the molecular activity calculated for purified Ca2+-ATPase (36 min-1). The Ca2+-dependent 32P incorporation in soleus muscle decreased in the order mice greater than rats greater than guinea pigs. In EDL muscles from hypothyroid rats at a 30% reduction of the Ca2+-dependent phosphorylation was observed. The Ca2+-dependent phosphorylation in vastus lateralis muscle from three human subjects amounted to 4.5 +/- 0.8 nmol/g wet wt. It is concluded that measurement of the Ca2+-dependent phosphorylation allows rapid and reproducible quantification of the concentration of Ca2+-dependent Mg2+-ATPase of sarcoplasmic reticulum. Since only 20-60 mg of tissue is required for the measurements, the method can also be used for biopsies obtained in clinical studies.

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The deleterious effects of bed rest on human skeletal muscle fibers are exacerbated by hypercortisolemia and ameliorated by dietary supplementation

AJP Cell Physiology ◽

10.1152/ajpcell.00573.2006 ◽

2007 ◽

Vol 293 (1) ◽

pp. C313-C320 ◽

Cited By ~ 69

Author(s):

R. H. Fitts ◽

J. G. Romatowski ◽

J. R. Peters ◽

D. Paddon-Jones ◽

R. R. Wolfe ◽

...

Keyword(s):

Peak Power ◽

Vastus Lateralis ◽

Sodium Succinate ◽

Muscle Fibers ◽

Caloric Intake ◽

Bed Rest ◽

Essential Amino Acids ◽

Peak Force ◽

Type I ◽

Type Ii

Prolonged inactivity associated with bed rest in a clinical setting or spaceflight is frequently associated with hypercortisolemia and inadequate caloric intake. Here, we determined the effect of 28 days of bed rest (BR); bed rest plus hypercortisolemia (BRHC); and bed rest plus essential amino acid (AA) and carbohydrate (CHO) supplement (BRAA) on the size and function of single slow- and fast-twitch muscle fibers. Supplementing meals, the BRAA group consumed 16.5 g essential amino acids and 30 g sucrose at 1100, 1600, and 2100 h, and the BRHC subjects received 5 daily doses of 10–15 mg of oral hydrocortisone sodium succinate throughout bed rest. Bed rest induced atrophy and loss of force (mN) and power (μN·FL·s−1) in single fibers was exacerbated by hypercortisolemia where soleus peak force declined by 23% in the type I fiber from a prevalue of 0.78 ± 0.02 to 0.60 ± 0.02 mN post bed rest (compared to a 7% decline with bed rest alone) and 27% in the type II fiber (1.10 ± 0.08 vs. 0.81 ± 0.05 mN). In the BRHC group, peak power dropped by 19, 15, and 11% in the soleus type I, and vastus lateralis (VL) type I and II fibers, respectively. The AA/CHO supplement protected against the bed rest-induced loss of peak force in the type I soleus and peak power in the VL type II fibers. These results provide evidence that an AA/CHO supplement might serve as a successful countermeasure to help preserve muscle function during periods of relative inactivity.

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Effects of 21 days of bed rest, with or without artificial gravity, on nutritional status of humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.91136.2008 ◽

2009 ◽

Vol 107 (1) ◽

pp. 54-62 ◽

Cited By ~ 30

Author(s):

S. R. Zwart ◽

G. E. Crawford ◽

P. L. Gillman ◽

G. Kala ◽

A. S. Rodgers ◽

...

Keyword(s):

Nutritional Status ◽

Rest Period ◽

Nutrient Status ◽

Bed Rest ◽

Blood Chemistry ◽

Artificial Gravity ◽

Blood Levels ◽

Negative Effects ◽

Vitamin Status ◽

Β Carotene

Spaceflight and bed rest models of microgravity have profound effects on physiological systems, including the cardiovascular, musculoskeletal, and immune systems. These effects can be exacerbated by suboptimal nutrient status, and therefore it is critical to monitor nutritional status when evaluating countermeasures to mitigate negative effects of spaceflight. As part of a larger study to investigate the usefulness of artificial gravity as a countermeasure for musculoskeletal and cardiovascular deficits during bed rest, we tested the hypothesis that artificial gravity would have an effect on some aspects of nutritional status. Dietary intake was recorded daily before, during, and after 21 days of bed rest with artificial gravity ( n = 8) or bed rest alone ( n = 7). We examined body composition, hematology, general blood chemistry, markers of oxidative damage, and blood levels of selected vitamins and minerals before, during, and after the bed rest period. Several indicators of vitamin status changed in response to diet changes: serum α- and γ-tocopherol and urinary 4-pyridoxic acid decreased ( P < 0.001) and plasma β-carotene increased ( P < 0.001) in both groups during bed rest compared with before bed rest. A decrease in hematocrit ( P < 0.001) after bed rest was accompanied by a decrease in transferrin (P < 0.001), but transferrin receptors were not changed. These data provide evidence that artificial gravity itself does not negatively affect nutritional status during bed rest. Likewise, artificial gravity has no protective effect on nutritional status during bed rest.

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Resistance Exercise Training in McArdle Disease: Myth or Reality?

Case Reports in Neurological Medicine ◽

10.1155/2018/9658251 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Aleksandra Pietrusz ◽

Renata S. Scalco ◽

Ros Quinlivan

Keyword(s):

Strength Training ◽

Rest Period ◽

Creatine Phosphate ◽

Muscular Contraction ◽

Mcardle Disease ◽

Specific Protocol ◽

Isometric Muscle Contraction ◽

Resistance Exercises ◽

Type Of Exercise

McArdle disease is a metabolic myopathy mainly characterised by symptom onset during physical activities or isometric muscle contraction. Resistance (also termed strength) training is a type of physical exercise focusing on the use of resistance (e.g., lifting weights) to induce muscular contraction, which builds muscle mass and strength. Historically people with McArdle disease were advised to avoid resistance exercises and any other form of physical activity involving high mechanical loads such as prolonged isometric contraction. Paradoxically, a clinical trial exploring the benefits of strength training in this patient population was published. The theory supporting strength training relied on the use of the ATP molecule and the creatine phosphate (ATP-phosphocreatine system) as energy sources for skeletal muscles. Here, we report two patients with McArdle disease who performed weight training at local gyms. A single set of repetitions lasted for maximum 10 seconds with minimum of 30 seconds of rest period in between sets of exercises. Benefits of this type of training included improvement in quality of life and amelioration of McArdle disease symptoms. We provide further safety evidence of this type of exercise in people with McArdle disease. We emphasise the importance of using a specific protocol developed for people affected by this condition.

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Stimulation of myofibrillar synthesis by exercise is mediated by more efficient translation of mRNA

Journal of Applied Physiology ◽

10.1152/jappl.1999.86.4.1220 ◽

1999 ◽

Vol 86 (4) ◽

pp. 1220-1225 ◽

Cited By ~ 70

Author(s):

Stephen Welle ◽

Kirti Bhatt ◽

Charles A. Thornton

Keyword(s):

Protein Synthesis ◽

Resistance Exercise ◽

Vastus Lateralis ◽

Mrna Translation ◽

Human Muscle ◽

Total Rna ◽

Resistance Exercises ◽

Actin Mrna ◽

Membrane Hybridization ◽

Stimulation Of

Resistance exercises stimulate protein synthesis in human muscle, but the roles of changes in mRNA concentrations and changes in the efficiency of mRNA translation have not been defined. The present study was done to determine whether resistance exercise affects concentrations of total RNA, total mRNA, actin mRNA, or myosin heavy-chain mRNA (total and isoform specific). Eight subjects, 62–75 yr old, performed unilateral knee extensions at 80% of their one-repetition-maximum capacity on days 1, 3, and 6 of the study. On day 7, biopsies of exercised and nonexercised vastus lateralis muscles were obtained. Myofibrillar synthesis was determined by stable- isotope incorporation, and mRNA concentrations were determined by membrane hybridization and PCR-based methods. The exercise stimulated myofibrillar synthesis [30 ± 6 (SE)%] without affecting RNA or mRNA concentrations. The effect of exercise on protein synthesis in individual subjects did not correlate with the effect on total RNA and mRNA concentrations. These data suggest that the stimulation of myofibrillar synthesis by resistance exercise is mediated by more efficient translation of mRNA.

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Electromyographic evaluation of high-intensity elastic resistance exercises for lower extremity muscles during bed rest

European Journal of Applied Physiology ◽

10.1007/s00421-017-3620-2 ◽

2017 ◽

Vol 117 (7) ◽

pp. 1329-1338 ◽

Cited By ~ 6

Author(s):

Jonas Vinstrup ◽

Sebastian Skals ◽

Joaquin Calatayud ◽

Markus Due Jakobsen ◽

Emil Sundstrup ◽

...

Keyword(s):

Lower Extremity ◽

High Intensity ◽

Bed Rest ◽

Elastic Resistance ◽

Resistance Exercises

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Strength training counteracts motor performance losses during bed rest

Journal of Applied Physiology ◽

10.1152/japplphysiol.01173.2002 ◽

2003 ◽

Vol 95 (4) ◽

pp. 1485-1492 ◽

Cited By ~ 51

Author(s):

Minoru Shinohara ◽

Yasuhide Yoshitake ◽

Motoki Kouzaki ◽

Hideoki Fukuoka ◽

Tetsuo Fukunaga

Keyword(s):

Strength Training ◽

Muscle Activation ◽

Vastus Lateralis ◽

Knee Extensor ◽

Bed Rest ◽

Training Group ◽

Medial Gastrocnemius ◽

Knee Extensors ◽

Extensor Muscles ◽

Muscle Groups

The purpose of the study was to determine the effect of bed rest with or without strength training on torque fluctuations and activation strategy of the muscles. Twelve young men participated in a 20-day bed rest study. Subjects were divided into a non-training group (BRCon) and a strength-training group (BRTr). The training comprised dynamic calf-raise and leg-press exercises. Before and after bed rest, subjects performed maximal contractions and steady submaximal isometric contractions of the ankle extensor muscles and of the knee extensor muscles (2.5-10% of maximal torque). Maximal torque decreased for both the ankle extensors (9%, P < 0.05) and knee extensors (16%, P < 0.05) in BRCon but not in BRTr. For the ankle extensors, the coefficient of variation (CV) for torque increased in both groups ( P < 0.05), with a greater amount ( P < 0.05) in BRCon (88%) compared with BRTr (41%). For the knee extensors, an increase in the CV for torque was observed only in BRCon (22%). The increase in the CV for torque in BRCon accompanied the greater changes in electromyogram amplitude of medial gastrocnemius (122%) and vastus lateralis (59%) compared with BRTr ( P < 0.05). The results indicate that fluctuations in torque during submaximal contractions of the extensor muscles in the leg increase after bed rest and that strength training counteracted the decline in performance. The response varied across muscle groups. Alterations in muscle activation may lead to an increase in fluctuations in motor output after bed rest.

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