scholarly journals The Study of Muscle, Mobility, and Aging (SOMMA): An Overview

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 125-125
Author(s):  
Steve Cummings ◽  
Peggy Cawthon ◽  
Russell Hepple
Keyword(s):  
Muscle Mass ◽  
Gait Speed ◽  
Vastus Lateralis ◽  
Cardiopulmonary Exercise Testing ◽  
Quadriceps Muscle ◽  
Biological Properties ◽  
Vastus Lateralis Muscle ◽  
Cognitive Assessments ◽  
And Function ◽  
Ancillary Studies

Abstract SOMMA is an NIA-funded cohort study to identify biological determinants of mobility and fitness. The overall aim of SOMMA is to use biopsies, novel biomarkers, advanced imaging, and intensive physical and cognitive assessments to elucidate the biological processes that contribute to changes in mobility and physical fitness with aging. SOMMA will recruit 875 people age 70+ (of whom about 200 have been enrolled.) We take biopsies of the vastus lateralis muscle to quantify mitochondrial content and function of the electron transport chain. We use 31PMR spectroscopy to quantify mitochondrial capacity to generate ATP in quadriceps muscle (ATPmax). We will quantify other biological properties in biopsies including denervation, autophagy and accumulated biochemical damage and use gene expression to discover pathways that contribute to mobility and fitness. SOMMA uses MR for quadriceps volume and D3Cr dilution for total skeletal muscle mass, cardiopulmonary exercise testing to measure fitness (VO2 peak). We are also making many other intensive assessments of physical and cognitive function. Mobility endpoints include baseline and three year change in 400 m and 4 meter gait speed and fitness. SOMMA is building a large biobank of muscle, adipose blood, and urine specimens that will be available for ancillary studies. In this Symposium, we will present results from analyses of associations between muscle mitochondrial function and strength, muscle mass, cognitive performance, gait speed, and fitness. The symposium will also preview opportunities for collaborations and ancillary studies with SOMMA.

Temporal disruption of neuromuscular communication and muscle atrophy following non-invasive ACL injury in rats

2021 ◽  
Author(s):  
Emily R. Hunt ◽  
Steven M. Davi ◽  
Cassandra N. Parise ◽  
Kaleigh Clark ◽  
Douglas W. Van Pelt ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Muscle Atrophy ◽  
Acl Injury ◽  
Quadriceps Muscle ◽  
Proteasome Activity ◽  
Vastus Lateralis Muscle ◽  
20S Proteasome ◽  
Post Injury ◽  
Non Invasive ◽  
Wet Weight

Many patients with anterior cruciate ligament (ACL) injuries have persistent quadriceps muscle atrophy, even after considerable time in rehabilitation. Understanding the factors that regulate muscle mass, and the time course of atrophic events, is important for identifying therapeutic interventions. Using a non-invasive animal model of ACL injury, a longitudinal study was performed to elucidate key parameters underlying quadriceps muscle atrophy. Male Long-Evans rats were euthanized at 6, 12, 24, 48-hrs and 1, 2, 4-wks after ACL injury that was induced via tibial compression overload; controls were not injured. Vastus Lateralis muscle size was determined by wet weight and fiber CSA. Evidence of disrupted neuromuscular communication was assessed via the expression of NCAM and genes associated with denervation and neuromuscular junction instability. Abundance of MuRF-1, MAFbx, and 45s pre-rRNA along with 20S proteasome activity were determined to investigate mechanisms related to muscle atrophy. Lastly, muscle damage-related parameters were assessed by measuring IgG permeability, centronucleation, CD68 mRNA and satellite cell abundance. Compared to controls, we observed a greater percentage of NCAM positive fibers at 6-hrs post-injury, followed by higher MAFbx abundance 48-hrs post-injury, and higher 20S proteasome activity at 1-wk post-injury. A loss of muscle wet weight, smaller fiber CSA and the elevated expression of Runx1 were also observed at the 1-wk post-injury time point relative to controls. There also were no differences observed in any damage markers. These results indicate that alterations in neuromuscular communication precede the upregulation of atrophic factors that regulate quadriceps muscle mass early after non-invasive ACL injury.

Effects of Ultratrail Running on Skeletal-Muscle Oxygenation Dynamics

2017 ◽  
Vol 12 (4) ◽  
pp. 496-504 ◽  
Author(s):  
Gianluca Vernillo ◽  
Alfredo Brighenti ◽  
Eloisa Limonta ◽  
Pietro Trabucchi ◽  
Davide Malatesta ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Vastus Lateralis ◽  
Oxygenation Index ◽  
Constant Load ◽  
Negative Influence ◽  
Muscle Oxygenation ◽  
Vastus Lateralis Muscle ◽  
Skeletal Muscle Oxygenation ◽  
Power Outputs ◽  
And Function

Purpose:To quantify changes in skeletal-muscle oxygenation and pulmonary O2 uptake (V̇O2) after an extreme ultratrail running bout.Methods:Before (PRE) and after (POST) the race (330-km, 24000 D±), profiles of vastus lateralis muscle oxygenation (ie, oxyhemoglobin [O2Hb], deoxyhemoglobin [HHb], and tissue oxygenation index [TOI]) and V̇O2 were determined in 14 athletes (EXP) and 12 control adults (CON) during two 4-min constant-load cycling bouts at power outputs of 1 (p1) and 1.5 (p1.5) W/kg performed in randomized order.Results:At POST, normalized [HHb] values increased (p1, +38.0%; p1.5, +27.9%; P < .05), while normalized [O2Hb] (p1, –20.4%; p1.5, –14.4%; P < .05) and TOI (p1, –17.0%; p1.5, –17.7%; P < .05) decreased in EXP. V̇O2 values were similar (P > 0.05). An “overshoot“ in normalized [HHb]:V̇O2 was observed, although the increase was significant only during p1.5 (+58.7%, P = .003). No difference in the aforementioned variables was noted in CON (P > .05).Conclusions:The concentric and, particularly, the eccentric loads characterizing this extreme ultratrail-running bout may have led to variations in muscle structure and function, increasing the local muscle deoxygenation profile and the imbalance between O2 delivery to working muscles and muscle O2 consumption. This highlights the importance of incorporating graded training, particularly downhill bouts, to reduce the negative influence of concentric and severe eccentric loads to the microcirculatory function and to enhance the ability of runners to sustain such loading.

Rate of fatigue during repeated submaximal contractions of human quadriceps muscle

1991 ◽  
Vol 69 (10) ◽  
pp. 1410-1415 ◽  
Author(s):  
T. Dolmage ◽  
E. Cafarelli
Keyword(s):  
Vastus Lateralis ◽  
Close Relation ◽  
Quadriceps Muscle ◽  
Surface Emg ◽  
Voluntary Contraction ◽  
Vastus Lateralis Muscle ◽  
Relaxation Rates ◽  
Twitch Characteristics ◽  
Rate Of Decline ◽  
Force Time

Our purpose was to determine the effect of eight different combinations of contraction intensity, duration, and rest on the rate of fatigue in vastus lateralis muscle. A single combination consisted of contractions at 30 or 70% maximal voluntary contraction (MVC), held for 3 or 7 s with 3- or 7-s rest intervals. Contractions were repeated until the subject could not hold the force for the requisite duration. At regular intervals during each experiment, a brief MVC, a single twitch, and the response to eight stimulation pulses at 50 Hz were elicited. The rate of fatigue was the rate of decline of MVC calculated from regression analysis. Mean rate of fatigue (n = 8) ranged from 0.3 to 25% MVC/min and was closely related (r = 0.98) to the product of the relative force and the duty cycle. Force from 50 Hz stimulation fell linearly and in parallel with MVC. Twitch force was first potentiated and then fell twice as fast as 50 Hz stimulation and MVC (p < 0.05). Differentiated twitch contraction and relaxation rates were higher at potentiation and lower at the limit of endurance, compared with control values (p < 0.05). The maximal electromyogram decreased 25% and the submaximal EMG increased to maximal by the end of the protocol, indicating that the entire motor unit pool had been recruited. The close relation between rate of fatigue and the force × time product probably reflects the off-setting interaction of contraction amplitude, duration, and rest interval. This occurs despite the changes in twitch characteristics and the apparent recruitment of fast fatiguing motor units.Key words: fatigue, surface EMG, limit of endurance, force × time product, twitch interpolation.

scholarly journals Damaging eccentric exercise attenuates disuse induced declines in daily myofibrillar protein synthesis and transiently prevents muscle atrophy in healthy men.

2021 ◽  
Author(s):  
Tom S. O. Jameson ◽  
Sean P Kilroe ◽  
Jonathan Fulford ◽  
Doaa Reda Abdelrahman ◽  
Andrew John Murton ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Eccentric Exercise ◽  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Quadriceps Strength ◽  
Myofibrillar Protein ◽  
Muscle Volume ◽  
Vastus Lateralis Muscle ◽  
Deuterated Water ◽  
Myofibrillar Protein Synthesis

Introduction: Short-term disuse leads to muscle loss driven by lowered daily myofibrillar protein synthesis (MyoPS). However, disuse commonly results from muscle damage, and its influence on muscle deconditioning during disuse is unknown. Methods: 21 males (20±1 y, BMI=24±1 kg·m-2 (±SEM)) underwent 7 days of unilateral leg immobilization immediately preceded by 300 bilateral, maximal, muscle-damaging eccentric quadriceps contractions (DAM; n=10) or no exercise (CON; n=11). Participants ingested deuterated water and underwent temporal bilateral thigh MRI scans and vastus lateralis muscle biopsies of immobilized (IMM) and non-immobilized (N-IMM) legs. Results: N-IMM quadriceps muscle volume remained unchanged throughout in both groups. IMM quadriceps muscle volume declined after 2 days by 1.7±0.5% in CON (P=0.031; and by 1.3±0.6% when corrected to N-IMM; P=0.06) but did not change in DAM, and declined equivalently in CON (by 6.4±1.1% [5.0±1.6% when corrected to N-IMM]) and DAM (by 2.6±1.8% [4.0±1.9% when corrected to N-IMM]) after 7 days. Immobilization began to decrease MyoPS compared with N-IMM in both groups after 2 days (P=0.109), albeit with higher MyoPS rates in DAM compared with CON (P=0.035). Frank suppression of MyoPS was observed between days 2-7 in CON (IMM=1.04±0.12, N-IMM=1.86±0.10%·d-1; P=0.002) but not DAM (IMM=1.49±0.29, N-IMM=1.90±0.30%·d-1; P>0.05). Declines in MyoPS and quadriceps volume after 7 days correlated positively in CON (R2=0.403; P=0.035) but negatively in DAM (R2=0.483; P=0.037). Quadriceps strength declined following immobilization in both groups, but to a greater extent in DAM. Conclusion: Prior muscle damaging eccentric exercise increases MyoPS and prevents loss of quadriceps muscle volume after 2 (but not 7) days of disuse.

scholarly journals Skeletal muscle oxidative function in vivo and ex vivo in athletes with marked hypertrophy from resistance training

2013 ◽  
Vol 114 (11) ◽  
pp. 1527-1535 ◽  
Author(s):  
Desy Salvadego ◽  
Rossana Domenis ◽  
Stefano Lazzer ◽  
Simone Porcelli ◽  
Jörn Rittweger ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Muscle Mass ◽  
Body Mass ◽  
Mitochondrial Respiration ◽  
Ex Vivo ◽  
Vastus Lateralis ◽  
Whole Body ◽  
Vastus Lateralis Muscle ◽  
Oxidative Function

Oxidative function during exercise was evaluated in 11 young athletes with marked skeletal muscle hypertrophy induced by long-term resistance training (RTA; body mass 102.6 ± 7.3 kg, mean ± SD) and 11 controls (CTRL; body mass 77.8 ± 6.0 kg). Pulmonary O2 uptake (V̇o2) and vastus lateralis muscle fractional O2 extraction (by near-infrared spectroscopy) were determined during an incremental cycle ergometer (CE) and one-leg knee-extension (KE) exercise. Mitochondrial respiration was evaluated ex vivo by high-resolution respirometry in permeabilized vastus lateralis fibers obtained by biopsy. Quadriceps femoris muscle cross-sectional area, volume (determined by magnetic resonance imaging), and strength were greater in RTA vs. CTRL (by ∼40%, ∼33%, and ∼20%, respectively). V̇o2peak during CE was higher in RTA vs. CTRL (4.05 ± 0.64 vs. 3.56 ± 0.30 l/min); no difference between groups was observed during KE. The O2 cost of CE exercise was not different between groups. When divided per muscle mass (for CE) or quadriceps muscle mass (for KE), V̇o2 peak was lower (by 15–20%) in RTA vs. CTRL. Vastus lateralis fractional O2 extraction was lower in RTA vs. CTRL at all work rates, during both CE and KE. RTA had higher ADP-stimulated mitochondrial respiration (56.7 ± 23.7 pmol O2·s−1·mg−1 ww) vs. CTRL (35.7 ± 10.2 pmol O2·s−1·mg−1 ww) and a tighter coupling of oxidative phosphorylation. In RTA, the greater muscle mass and maximal force and the enhanced mitochondrial respiration seem to compensate for the hypertrophy-induced impaired peripheral O2 diffusion. The net results are an enhanced whole body oxidative function at peak exercise and unchanged efficiency and O2 cost at submaximal exercise, despite a much greater body mass.

scholarly journals Neuromuscular fatigue during a long-duration cycling exercise

2002 ◽  
Vol 92 (4) ◽  
pp. 1487-1493 ◽  
Author(s):  
Romuald Lepers ◽  
Nicola A. Maffiuletti ◽  
Ludovic Rochette ◽  
Julien Brugniaux ◽  
Guillaume Y. Millet
Keyword(s):  
Time Course ◽  
Muscle Activation ◽  
Mechanical Response ◽  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Voluntary Contraction ◽  
Vastus Lateralis Muscle ◽  
Electromyographic Activity ◽  
Cycling Exercise ◽  
M Wave

The effects of prolonged cycling on neuromuscular parameters were studied in nine endurance-trained subjects during a 5-h exercise sustained at 55% of the maximal aerobic power. Torque during maximal voluntary contraction (MVC) of the quadriceps muscle decreased progressively throughout the exercise ( P < 0.01) and was 18% less at the end of exercise compared with the preexercise value. Peak twitch torque, contraction time, and total area of mechanical response decreased significantly ( P < 0.05) after the first hour of exercise. In contrast, changes in M-wave characteristics were significant only after the fourth hour of the exercise. Significant reductions ( P < 0.05) in electromyographic activity normalized to the M wave occurred after the first hour for the vastus lateralis muscle but only at the end of the exercise for the vastus medialis muscle. Muscle activation level, assessed by the twitch interpolation technique, decreased by 8% ( P < 0.05) at the end of the exercise. The results suggest that the time course is such that the contractile properties are significantly altered after the first hour, whereas excitability and central drive are more impaired toward the latter stages of the 5-h cycling exercise.

scholarly journals Metabolic phenotype of skeletal muscle in early critical illness

Thorax ◽  
2018 ◽  
Vol 73 (10) ◽  
pp. 926-935 ◽  
Author(s):  
Zudin A Puthucheary ◽  
Ronan Astin ◽  
Mark J W Mcphail ◽  
Saima Saeed ◽  
Yasmin Pasha ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Critical Illness ◽  
Muscle Mass ◽  
Mitochondrial Biogenesis ◽  
Vastus Lateralis ◽  
Metabolic Phenotype ◽  
Tumour Necrosis Factor Receptor ◽  
Vastus Lateralis Muscle ◽  
Atp Content ◽  
Mitochondrial Dna Copy Number

ObjectivesTo characterise the sketetal muscle metabolic phenotype during early critical illness.MethodsVastus lateralis muscle biopsies and serum samples (days 1 and 7) were obtained from 63 intensive care patients (59% male, 54.7±18.0 years, Acute Physiology and Chronic Health Evaluation II score 23.5±6.5).Measurements and main resultsFrom day 1 to 7, there was a reduction in mitochondrial beta-oxidation enzyme concentrations, mitochondrial biogenesis markers (PGC1α messenger mRNA expression (−27.4CN (95% CI −123.9 to 14.3); n=23; p=0.025) and mitochondrial DNA copy number (−1859CN (IQR −5557–1325); n=35; p=0.032). Intramuscular ATP content was reduced compared tocompared with controls on day 1 (17.7mmol/kg /dry weight (dw) (95% CI 15.3 to 20.0) vs. 21.7 mmol/kg /dw (95% CI 20.4 to 22.9); p<0.001) and decreased over 7 days (−4.8 mmol/kg dw (IQR −8.0–1.2); n=33; p=0.001). In addition, the ratio of phosphorylated:total AMP-K (the bioenergetic sensor) increased (0.52 (IQR −0.09–2.6); n=31; p<0.001). There was an increase in intramuscular phosphocholine (847.2AU (IQR 232.5–1672); n=15; p=0.022), intramuscular tumour necrosis factor receptor 1 (0.66 µg (IQR −0.44–3.33); n=29; p=0.041) and IL-10 (13.6 ng (IQR 3.4–39.0); n=29; p=0.004). Serum adiponectin (10.3 µg (95% CI 6.8 to 13.7); p<0.001) and ghrelin (16.0 ng/mL (IQR −7–100); p=0.028) increased. Network analysis revealed a close and direct relationship between bioenergetic impairment and reduction in muscle mass and between intramuscular inflammation and impaired anabolic signaling. ATP content and muscle mass were unrelated to lipids delivered.ConclusionsDecreased mitochondrial biogenesis and dysregulated lipid oxidation contribute to compromised skeletal muscle bioenergetic status. In addition, intramuscular inflammation was associated with impaired anabolic recovery with lipid delivery observed as bioenergetically inert. Future clinical work will focus on these key areas to ameliorate acute skeletal muscle wasting.Trial registration numberNCT01106300.

scholarly journals Resistance Training With Partial Blood Flow Restriction in a 99-Year-Old Individual: A Case Report

2021 ◽  
Vol 3 ◽  
Author(s):  
Maíra Camargo Scarpelli ◽  
João Guilherme Almeida Bergamasco ◽  
Estevan A. de Barros Arruda ◽  
Summer B. Cook ◽  
Cleiton Augusto Libardi
Keyword(s):  
Quality Of Life ◽  
Blood Flow ◽  
Resistance Training ◽  
Muscle Mass ◽  
Vastus Lateralis ◽  
Blood Flow Restriction ◽  
Vastus Lateralis Muscle ◽  
Timed Up And Go ◽  
Flow Restriction

In aging populations for which the use of high loads is contraindicated, low load resistance training associated with blood flow restriction (RT-BFR) is an alternative strategy to induce muscle mass gains. This study investigates the effects of RT-BFR on muscle mass, muscle function, and quality of life of a 99-year-old patient with knee osteoarthritis and advanced muscle mass deterioration. Training protocol consisted of 24 sessions of a unilateral free-weight knee extension exercise associated with partial blood flow restriction through a manometer cuff set at 50% of complete vascular occlusion pressure. We evaluated: cross-sectional area (CSA) and thickness (MT) of the vastus lateralis muscle by ultrasound; function through the Timed Up and Go (TUG) test; and quality of life (QoL) by the WHOQOL-bref, WHOQOL-OLD and WOMAC questionnaires. All tests were performed prior to the training period (Pre) and after the 12th (Mid) and 24th (Post) sessions. Changes were considered significant if higher than 2 times the measurement's coefficient of variation (CV). After 24 sessions, there was an increase of 12% in CSA and 8% in MT. Questionnaires scores and TUG values worsened from Pre to Mid and returned in Post. We consider RT-BFR a viable and effective strategy to promote muscle mass gains in nonagenarians and delay the decline in functionality and QoL associated with aging.

MO588DECREASED IL-15 PRODUCTION INDUCED BY HYPERPHOSPHATEMIA AS A POSSIBLE MECHANISM OF AGED-RELATED SARCOPENIA*

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Elena Alcalde-Estévez ◽  
Ana Asenjo-Bueno ◽  
Gemma Olmos ◽  
Diego Rodríguez-Puyol ◽  
Susana López-Ongil ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Muscle Mass ◽  
Quadriceps Muscle ◽  
Serum Phosphate ◽  
In Vivo Studies ◽  
And Function ◽  
Old Mice

Abstract Background and Aims The loss of muscle mass and function, termed sarcopenia, is an aging-related condition associated to some important diseases such as chronic kidney disease (CKD). Hyperphosphatemia has been related to both pathologies. A chronic subclinical inflammation and a dysregulated immune system function are associated to aging affecting to multiple pathways in the skeletal muscle, and this fact has been linked to the development of sarcopenia. Interleukin-15 (IL-15) is a skeletal muscle-derived cytokine which promotes muscle regeneration. The aim of this work was to analyze the role of hyperphosphatemia on the IL-15 production of the skeletal muscle and its implication in aging-related sarcopenia. Method Cultured C2C12 myoblasts were used for in vitro experiments. Cells were treated with 10 mM beta-glycerophosphate (BGP) as a phosphate donor for 2, 4, 6, 8 and 24 hours. IL-15 mRNA levels were assessed by RT-qPCR. Three groups of C57BL6 male mice were used for the in vivo studies: 5-months-old mice (young), 24-month-old mice fed with a standard diet containing 0.6 % of phosphate (old) and 24-month-old mice fed with a hypophosphatemic diet, containing a 0.2% of phosphate (old+lowPi), for the last three months before sacrifice. Muscle force was measured by a grip test. Serum phosphate levels were analyzed with a commercial kit. Quadriceps muscle samples were collected to evaluate in them the IL-15 mRNA expression by RT-qPCR. Results C2C12 cells treated with BGP show a significant decrease in the IL-15 mRNA expression. On the other hand, in vivo studies showed that old mice had an increase in serum phosphate concentration and a reduction in forelimb strength and muscle mass, compared to young mice. Old animals fed with the hypophosphatemic diet displayed lower levels of phosphate serum linked to an improvement in the muscle mass and function. IL-15 expression of quadriceps muscle was reduced in old mice compared to young mice, whereas those values were increased in old mice fed with the low phosphate diet. Furthermore, there was a negative correlation between IL-15 expression levels and serum phosphate concentrations and a positive correlation between IL-15 and forelimb strength and muscle mass, suggesting that a decreased IL-15 expression affects muscle function. Conclusion High extracellular phosphate concentrations decrease IL-15 mRNA expression in myoblasts, and it is correlated with low IL-15 mRNA expression in the quadriceps muscle isolated from old mice. This reduction was associated to a decreased muscular strength and muscle mass, whereas the dietary restriction of phosphate improved these features. These results point to a role of hyperphosphatemia in the impaired immune system function, disrupting the skeletal muscle function, and this could be involved in aging and CKD-related sarcopenia.

scholarly journals Greater loss in muscle mass and function but smaller metabolic alterations in older compared with younger men following 2 wk of bed rest and recovery

2016 ◽  
Vol 120 (8) ◽  
pp. 922-929 ◽  
Author(s):  
Rado Pišot ◽  
Uros Marusic ◽  
Gianni Biolo ◽  
Sara Mazzucco ◽  
Stefano Lazzer ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Stride Length ◽  
Isometric Force ◽  
Bed Rest ◽  
Quadriceps Muscle ◽  
Metabolic Alterations ◽  
Homocysteine Concentration ◽  
Matsuda Index ◽  
Postprandial Lipid ◽  
And Function

This investigation aimed to compare the response of young and older adult men to bed rest (BR) and subsequent rehabilitation (R). Sixteen older (OM, age 55-65 yr) and seven young (YM, age 18–30 yr) men were exposed to a 14-day period of BR followed by 14 days of R. Quadriceps muscle volume (QVOL), force (QF), and explosive power (QP) of leg extensors; single-fiber isometric force (Fo); peak aerobic power (V̇o2peak); gait stride length; and three metabolic parameters, Matsuda index of insulin sensitivity, postprandial lipid curve, and homocysteine plasma level, were measured before and after BR and after R. Following BR, QVOL was smaller in OM (−8.3%) than in YM (−5.7%, P = 0.031); QF (−13.2%, P = 0.001), QP (−12.3%, P = 0.001), and gait stride length (−9.9%, P = 0.002) were smaller only in OM. Fo was significantly smaller in both YM (−32.0%) and OM (−16.4%) without significant differences between groups. V̇o2peak decreased more in OM (−15.3%) than in YM (−7.6%, P < 0.001). Instead, the Matsuda index fell to a greater extent in YM than in OM (−46.0% vs. −19.8%, respectively, P = 0.003), whereas increases in postprandial lipid curve (+47.2%, P = 0.013) and homocysteine concentration (+26.3%, P = 0.027) were observed only in YM. Importantly, after R, the recovery of several parameters, among them QVOL, QP, and V̇o2peak, was not complete in OM, whereas Fo did not recover in either age group. The results show that the effect of inactivity on muscle mass and function is greater in OM, whereas metabolic alterations are greater in YM. Furthermore, these findings show that the recovery of preinactivity conditions is slower in OM.

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