scholarly journals Initial Results From SOMMA: Contribution of Mitochondrial Function to Walking and Fitness

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 125-125
Author(s):  
Steve Cummings ◽  
Peggy Cawthon ◽  
Bret Goodpaster ◽  
Russell Hepple ◽  
Nancy W Glynn ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Walking Speed ◽  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Peak Oxygen Consumption ◽  
Strongly Correlated ◽  
Treadmill Testing ◽  
Initial Results ◽  
Mitochondrial Capacity

Abstract We hypothesize that the capacity of mitochondria in quadriceps skeletal muscle to generate ATP energy by respirometry (OXPHOS) in biopsies from the vastus lateralis, and in whole quadriceps muscle by 31PMRS (ATPmax) would contribute to 4 and 400m gait speed and to peak oxygen consumption on treadmill testing (VO2peak). In analyses from the first SOMMA participants recruited (N=122), OXPHOS was similarly associated with 4m (r=0.21) and 400 m (r=0.21) walking speed (P<0.01). However, ATPmax was not associated with either 4m or 400m walking speed (r=-0.02 and -0.07 respectively). In contrast both OXPHOS (r=0.43) and ATP max (r=0.35) were more strongly correlated with fitness (VO2 peak). These findings suggest that in older people, the mitochondrial capacity to generate ATP plays an important role walking speed and may be even more important to fitness.

Reversal of muscle fatigue during 16 h of heavy intermittent cycle exercise

2004 ◽  
Vol 97 (6) ◽  
pp. 2166-2175 ◽  
Author(s):  
H. J. Green ◽  
T. A. Duhamel ◽  
S. Ferth ◽  
G. P. Holloway ◽  
M. M. Thomas ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Muscle Fatigue ◽  
Intermittent Exercise ◽  
Low Frequency ◽  
Quadriceps Muscle ◽  
Stimulation Frequency ◽  
Peak Oxygen Consumption ◽  
Force Frequency ◽  
Reduction In Force ◽  
Before And After

This study examined the effects of extended sessions of heavy intermittent exercise on quadriceps muscle fatigue and weakness. Twelve untrained volunteers (10 men and 2 women), with a peak oxygen consumption of 44.3 ± 2.3 ml·kg−1·min−1, exercised at ∼91% peak oxygen consumption for 6 min once per hour for 16 h. Muscle isometric properties assessed before and after selected repetitions (R1, R2, R4, R7, R12, and R15) were used to quantitate fatigue (before vs. after repetitions) and weakness (before vs. before repetitions). Muscle fatigue at R1 was indicated by reductions ( P < 0.05) in peak twitch force (135 ± 13 vs. 106 ± 11 N) and by a reduction ( P < 0.05) in the force-frequency response, which ranged between ∼53% at 10 Hz (113 ± 12 vs. 52.6 ± 7.4 N) and ∼17% at 50 Hz (324 ± 27 vs. 270 ± 30 N). No recovery of force, regardless of stimulation frequency, was observed during the 54 min between R1 and R2. At R2 and for all subsequent repetitions, no reduction in force, regardless of stimulation frequency, was generally found after the exercise. The only exception was for R2, where, at 20 Hz, force was reduced ( P < 0.05) by 18%. At R15, force before repetitions for high frequencies (i.e., 100 Hz) returned to R1 (333 ± 29 vs. 324 ± 27 N), whereas force at low frequency (i.e., 10 Hz) was only partially ( P < 0.05) recovered (113 ± 12 vs. 70 ± 6.6 N). It is concluded that multiple sessions of heavy exercise can reverse the fatigue noted early and reduce or eliminate weakness depending on the frequency of stimulation.

scholarly journals Cardiovascular and skeletal muscle health with lifelong exercise

2018 ◽  
Vol 125 (5) ◽  
pp. 1636-1645 ◽  
Author(s):  
Kevin J. Gries ◽  
Ulrika Raue ◽  
Ryan K. Perkins ◽  
Kaleen M. Lavin ◽  
Brittany S. Overstreet ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Aerobic Exercise ◽  
Muscle Biopsy ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Metabolic Phenotype ◽  
Vastus Lateralis Muscle ◽  
Metabolic Fitness ◽  
Lifelong Exercise

The purpose of this study was to examine the effects of aerobic lifelong exercise (LLE) on maximum oxygen consumption (V̇o2max) and skeletal muscle metabolic fitness in trained women ( n = 7, 72 ± 2 yr) and men ( n = 21, 74 ± 1 yr) and compare them to old, healthy nonexercisers (OH; women: n = 10, 75 ± 1 yr; men: n = 10, 75 ± 1 yr) and young exercisers (YE; women: n = 10, 25 ± 1 yr; men: n = 10, 25 ± 1 yr). LLE men were further subdivided based on intensity of lifelong exercise and competitive status into performance (LLE-P, n = 14) and fitness (LLE-F, n = 7). On average, LLE exercised 5 day/wk for 7 h/wk over the past 52 ± 1 yr. Each subject performed a maximal cycle test to assess V̇o2maxand had a vastus lateralis muscle biopsy to examine capillarization and metabolic enzymes [citrate synthase, β-hydroxyacyl-CoA dehydrogenase (β-HAD), and glycogen phosphorylase]. V̇o2maxhad a hierarchical pattern (YE > LLE > OH, P < 0.05) for women (44 ± 2 > 26 ± 2 > 18 ± 1 ml·kg−1·min−1) and men (53 ± 3 > 34 ± 1 > 22 ± 1 ml·kg−1·min−1) and was greater ( P < 0.05) in LLE-P (38 ± 1 ml·kg−1·min−1) than LLE-F (27 ± 2 ml·kg−1·min−1). LLE men regardless of intensity and women had similar capillarization and aerobic enzyme activity (citrate synthase and β-HAD) as YE, which were 20%–90% greater ( P < 0.05) than OH. In summary, these data show a substantial V̇o2maxbenefit with LLE that tracked similarly between the sexes, with further enhancement in performance-trained men. For skeletal muscle, 50+ years of aerobic exercise fully preserved capillarization and aerobic enzymes, regardless of intensity. These data suggest that skeletal muscle metabolic fitness may be easier to maintain with lifelong aerobic exercise than more central aspects of the cardiovascular system.NEW & NOTEWORTHY Lifelong exercise (LLE) is a relatively new and evolving area of study with information especially limited in women and individuals with varying exercise intensity habits. These data show a substantial maximal oxygen consumption benefit with LLE that tracked similarly between the sexes. Our findings contribute to the very limited skeletal muscle biopsy data from LLE women (>70 yr), and similar to men, revealed a preserved metabolic phenotype comparable to young exercisers.

Subcellular localization-dependent decrements in skeletal muscle glycogen and mitochondria content following short-term disuse in young and old men

2010 ◽  
Vol 299 (6) ◽  
pp. E1053-E1060 ◽  
Author(s):  
Joachim Nielsen ◽  
Charlotte Suetta ◽  
Lars G. Hvid ◽  
Henrik D. Schrøder ◽  
Per Aagaard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Age Groups ◽  
Quadriceps Muscle ◽  
Fiber Types ◽  
Short Term ◽  
Skeletal Muscle Glycogen ◽  
Before And After ◽  
Old Men

Previous studies have shown that skeletal muscle glycogen and mitochondria are distributed in distinct subcellular localizations, but the role and regulation of these subcellular localizations are unclear. In the present study, we used transmission electron microscopy to investigate the effect of disuse and aging on human skeletal muscle glycogen and mitochondria content in subsarcolemmal (SS), intermyofibrillar (IMF), and intramyofibrillar (intra) localizations. Five young (∼23 yr) and five old (∼66 yr) recreationally active men had their quadriceps muscle immobilized for 2 wk by whole leg casting. Biopsies were obtained from m. vastus lateralis before and after the immobilization period. Immobilization induced a decrement of intra glycogen content by 54% ( P < 0.001) in both age groups and in two ultrastructurally distinct fiber types, whereas the content of IMF and SS glycogen remained unchanged. A localization-dependent decrease ( P = 0.03) in mitochondria content following immobilization was found in both age groups, where SS mitochondria decreased by 33% ( P = 0.02), superficial IMF mitochondria decreased by 20% ( P = 0.05), and central IMF mitochondria remained unchanged. In conclusion, our findings demonstrate a localization-dependent adaptation to immobilization in glycogen and mitochondria content of skeletal muscles of both young and old individuals. Specifically, this suggests that short-term disuse preferentially affects glycogen particles located inside the myofibrils and that mitochondria volume plasticity can be dependent on the distance to the fiber border.

Peak oxygen consumption and skeletal muscle bioenergetics in African-American and Caucasian men

2000 ◽  
Vol 32 (12) ◽  
pp. 2059-2066 ◽  
Author(s):  
RICHARD R. SUMINSKI ◽  
ROBERT J. ROBERTSON ◽  
FREDRIC L. GOSS ◽  
and SILVA ARSLANIAN
Keyword(s):  
Skeletal Muscle ◽  
African American ◽  
Oxygen Consumption ◽  
Peak Oxygen Consumption ◽  
Caucasian Men

ESTIMATION OF PEAK OXYGEN CONSUMPTION IN CARDIAC PATIENTS UNDERGOING RAMP TREADMILL TESTING 115

1996 ◽  
Vol 28 (Supplement) ◽  
pp. 20
Author(s):  
J. L. Fox ◽  
P. H. Brubaker ◽  
M. J. Berry ◽  
W. E. Pollock ◽  
H. Miller
Keyword(s):  
Oxygen Consumption ◽  
Cardiac Patients ◽  
Peak Oxygen Consumption ◽  
Treadmill Testing

Muscle cellular properties in the ice hockey player: a model for investigating overtraining?

2012 ◽  
Vol 90 (5) ◽  
pp. 567-578 ◽  
Author(s):  
Howard J. Green ◽  
Aziz Batada ◽  
Bill Cole ◽  
Margaret E. Burnett ◽  
Helen Kollias ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
G Protein ◽  
Vastus Lateralis ◽  
Succinic Dehydrogenase ◽  
Maximal Activity ◽  
Ice Hockey ◽  
Peak Oxygen Consumption ◽  
Cross Sectional ◽  
Hockey Players ◽  
Wet Weight

In this study, we hypothesized that athletes involved in 5–6 months of sprint-type training would display higher levels of proteins and processes involved in muscle energy supply and utilization. Tissue was sampled from the vastus lateralis of 13 elite ice hockey players (peak oxygen consumption = 51.8 ± 1.3 mL·kg–1·min–1; mean ± standard error) at the end of a season (POST) and compared with samples from 8 controls (peak oxygen consumption = 45.5 ± 1.4 mL·kg–1·min–1) (CON). Compared with CON, higher activities were observed in POST (p < 0.05) only for succinic dehydrogenase (3.32 ± 0.16 mol·(mg protein)–1·min–1 vs. 4.10 ± 0.11 mol·(mg protein)–1·min–1) and hexokinase (0.73 ± 0.05 mol·(mg protein)–1·min–1 vs. 0.90 ± 0.05mol·(mg protein)–1·min–1) but not for phosphorylase, phosphofructokinase, and creatine phosphokinase. No differences were found in Na+,K+-ATPase concentration (βmax: 262 ± 36 pmol·(g wet weight)–1 vs. 275 ± 27 pmol·(g wet weight)–1) and the maximal activity of the sarcoplasmic reticulum Ca2+-ATPase (98.1 ± 6.1 µmol·(g protein)–1·min–1 vs. 102 ± 3.3 µmol·(g protein)–1·min–1). Cross-sectional area was lower (p < 0.05) in POST but only for the type IIA fibres (6312 ± 684 μm2 vs. 5512 ± 335 μm2), while the number of capillary counts per fibre and the capillary to fibre area ratio were generally higher (p < 0.05). These findings suggest that elite trained ice hockey players display elevations only in support of glucose-based aerobic metabolism that occur in the absence of alterations in excitation–contraction processes.

scholarly journals Noninvasive evaluation of skeletal muscle mitochondrial capacity with near-infrared spectroscopy: correcting for blood volume changes

2012 ◽  
Vol 113 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Terence E. Ryan ◽  
Melissa L. Erickson ◽  
Jared T. Brizendine ◽  
Hui-Ju Young ◽  
Kevin K. McCully
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Oxygen Consumption ◽  
Infrared Spectroscopy ◽  
Blood Volume ◽  
Near Infrared ◽  
Tissue Thickness ◽  
Volume Changes ◽  
Mitochondrial Capacity

Near-infrared spectroscopy (NIRS) is a well-known method used to measure muscle oxygenation and hemodynamics in vivo. The application of arterial occlusions allows for the assessment of muscle oxygen consumption (mV̇o2) using NIRS. The aim of this study was to measure skeletal muscle mitochondrial capacity using blood volume-corrected NIRS signals that represent oxygenated hemoglobin/myoglobin (O2Hb) and deoxygenated hemoglobin/myoglobin (HHb). We also assessed the reliability and reproducibility of NIRS measurements of resting oxygen consumption and mitochondrial capacity. Twenty-four subjects, including four with chronic spinal cord injury, were tested using either the vastus lateralis or gastrocnemius muscles. Ten healthy, able-bodied subjects were tested on two occasions within a period of 7 days to assess the reliability and reproducibility. NIRS signals were corrected for blood volume changes using three different methods. Resting oxygen consumption had a mean coefficient of variation (CV) of 2.4% (range 1–32%). The recovery of oxygen consumption (mV̇o2) after electrical stimulation at 4 Hz was fit to an exponential curve, which represents mitochondrial capacity. The time constant for the recovery of mV̇o2was reproducible with a mean CV of 10% (range 1–22%) only when correcting for blood volume changes. We also examined the effects of adipose tissue thickness on measurements of mV̇o2. We found the mV̇o2measurements using absolute units to be influenced by adipose tissue thickness (ATT), and this relationship was removed when an ischemic calibration was performed, supporting its use to compare mV̇o2between individuals of varying ATT. In conclusion, in vivo oxidative capacity can be assessed using blood volume-corrected NIRS signals with a high degree of reliability and reproducibility.

scholarly journals Accuracy and precision of quantitative 31P-MRS measurements of human skeletal muscle mitochondrial function

2016 ◽  
Vol 311 (2) ◽  
pp. E358-E366 ◽  
Author(s):  
Gwenael Layec ◽  
Jayson R. Gifford ◽  
Joel D. Trinity ◽  
Corey R. Hart ◽  
Ryan S. Garten ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Atp Synthesis ◽  
Synthesis Rate ◽  
Resonance Spectroscopy ◽  
Phosphorylation Potential ◽  
Accuracy And Precision ◽  
Mitochondrial Capacity

Although theoretically sound, the accuracy and precision of 31P-magnetic resonance spectroscopy (31P-MRS) approaches to quantitatively estimate mitochondrial capacity are not well documented. Therefore, employing four differing models of respiratory control [linear, kinetic, and multipoint adenosine diphosphate (ADP) and phosphorylation potential], this study sought to determine the accuracy and precision of 31P-MRS assessments of peak mitochondrial adenosine-triphosphate (ATP) synthesis rate utilizing directly measured peak respiration (State 3) in permeabilized skeletal muscle fibers. In 23 subjects of different fitness levels, 31P-MRS during a 24-s maximal isometric knee extension and high-resolution respirometry in muscle fibers from the vastus lateralis was performed. Although significantly correlated with State 3 respiration ( r = 0.72), both the linear (45 ± 13 mM/min) and phosphorylation potential (47 ± 16 mM/min) models grossly overestimated the calculated in vitro peak ATP synthesis rate ( P < 0.05). Of the ADP models, the kinetic model was well correlated with State 3 respiration ( r = 0.72, P < 0.05), but moderately overestimated ATP synthesis rate ( P < 0.05), while the multipoint model, although being somewhat less well correlated with State 3 respiration ( r = 0.55, P < 0.05), most accurately reflected peak ATP synthesis rate. Of note, the PCr recovery time constant (τ), a qualitative index of mitochondrial capacity, exhibited the strongest correlation with State 3 respiration ( r = 0.80, P < 0.05). Therefore, this study reveals that each of the 31P-MRS data analyses, including PCr τ, exhibit precision in terms of mitochondrial capacity. As only the multipoint ADP model did not overstimate the peak skeletal muscle mitochondrial ATP synthesis, the multipoint ADP model is the only quantitative approach to exhibit both accuracy and precision.

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