scholarly journals NMES-Resistance Training Enhances Oxygen Uptake and Ventilatory Efficiency Independent of Mitochondrial Complexes after SCI: A Randomized Clinical Trial

2021 ◽  
Author(s):  
Ashraf S. Gorgey ◽  
Raymond E. Lai ◽  
Refka E. Khalil ◽  
Jeannie F. Rivers ◽  
Christopher P. Cardozo ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Resistance Training ◽  
Complex I ◽  
Muscle Hypertrophy ◽  
Knee Extensor ◽  
Mitochondrial Complex ◽  
Post Intervention ◽  
Ventilatory Efficiency ◽  
Cord Injury ◽  
Mitochondrial Complexes

The purpose of the study was to determine whether neuromuscular electrical stimulation resistance training (NMES-RT) evoked muscle hypertrophy is accompanied by increased VO2 peak, ventilatory efficiency and mitochondrial respiration in individuals with chronic spinal cord injury (SCI). Thirty-three men and women with chronic, predominantly traumatic, SCI were randomized to either NMES-RT (n=20) or passive movement training (PMT; n=13). Functional electrical stimulation-lower extremity cycling (FES-LEC) was used to test leg VO2 peak, VE/VCO2 ratio and substrate utilization prior to and post-intervention. Magnetic resonance imaging was used to measure muscle cross-sectional area (CSA). Finally, muscle biopsy was performed to measure mitochondrial complexes and respiration. The NMES-RT group showed a significant increase in post-intervention VO2 peak compared to baseline (∆ VO2 = 14%, P < 0.01) with no changes in the PMT group (∆ VO2 = 1.6%, P= 0.47). Similarly, thigh (∆ CSA Thigh = 19%) and knee extensor (∆ CSA Knee = 30.4 %, P < 0.01) CSAs increased following NMES-RT but not after PMT. The changes in thigh and knee extensor muscle CSAs were positively related with the change in VO2 peak. Neither NMES-RT nor PMT changed mitochondrial complex tissue levels; however, changes in peak VO2 were related to complex I. In conclusion, in persons with SCI, NMES-RT-induced skeletal muscle hypertrophy was accompanied with increased peak VO2 consumption which may partially be explained by enhanced activity of mitochondrial complex I.

scholarly journals Skeletal Muscle Hypertrophy and Attenuation of Cardio-Metabolic Risk Factors (SHARC) Using Functional Electrical Stimulation-Lower Extremity Cycling in Persons with Spinal Cord Injury. Study Protocol for a randomized clinical trial

2019 ◽  
Author(s):  
Ashraf Gorgey ◽  
Refka E Khalil ◽  
John C Davis ◽  
William Carter ◽  
Ranjodh Gill ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Insulin Sensitivity ◽  
Oxygen Uptake ◽  
Intracellular Signaling ◽  
Muscle Hypertrophy ◽  
Passive Movement ◽  
Control Group ◽  
Post Intervention ◽  
Glucose Effectiveness ◽  
Cord Injury

Abstract Background Persons with spinal cord injury (SCI) are at heightened risks of developing unfavorable cardiometabolic consequences due to physical inactivity. Functional electrical stimulation (FES) and surface neuromuscular electrical stimulation (NMES)-resistance training (RT) have emerged as effective rehabilitation methods that can exercise muscles below the level of injury and attenuate cardio-metabolic risk factors. Our aims are to: determine the impact of 12 weeks of NMES+12 weeks of FES-Lower extremity cycling (LEC) compared to 12 weeks of passive movement + 12 weeks of FES-LEC on 1) oxygen uptake (VO2), insulin sensitivity and glucose disposal in adults with SCI; 2) skeletal muscle size, intramuscular fat (IMF) and visceral adipose tissue (VAT) and; 3) determinants of energy metabolism, protein molecules involved in insulin signaling, muscle hypertrophy and oxygen uptake (IRS-1, AMPK, GLUT-4, IGF-1, mTOR, Akt and PGC-1 α) and electron transport chain (ETC) activities. Methods/Design Forty-eight persons aged 18-65 years with chronic (> 1 year) SCI/D (AIS A-C) at the C5-L2 levels, equally sub-grouped by cervical or sub-cervical injury levels and time since injury, will be randomized into either NMES+FES group or Passive + FES (control group). The NMES+FES group will undergo 12 weeks of evoked RT using twice-weekly NMES and ankle weights followed by twice-weekly progressive FES-LEC for an additional 12 weeks. The control group will undergo 12 weeks of passive movement followed by 12 weeks of progressive FES-LEC. Measurements will be performed at baseline (B; week 0), post-intervention 1 (P1; week 13) and post-intervention 2 (P2; week 25) and will include VO2 measurements, insulin sensitivity and glucose effectiveness using intravenous glucose tolerance; magnetic resonance imaging to measure muscle, IMF and VAT areas; muscle biopsy to measure protein expression and intracellular signaling as well as mitochondrial ETC function. Discussion Training through NMES+RT may evoke muscle hypertrophy and positively impact oxygen uptake, insulin sensitivity and glucose effectiveness. This may result in beneficial outcomes on metabolic activity, body composition profile, mitochondrial ETC and intracellular signaling related to insulin action and muscle hypertrophy. In the future, NMES-RT may be added to FES-LEC to improve the workloads achieved in the rehabilitation of SCI persons and further decrease muscle wasting and cardio-metabolic risks. Clinical trials # NCT02660073

scholarly journals Skeletal Muscle Hypertrophy and Attenuation of Cardio-Metabolic Risk Factors (SHARC) Using Functional Electrical Stimulation-Lower Extremity Cycling in Persons with Spinal Cord Injury. Study Protocol for a randomized clinical trial

2019 ◽  
Author(s):  
Ashraf Gorgey ◽  
Refka E Khalil ◽  
John C Davis ◽  
William Carter ◽  
Ranjodh Gill ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Insulin Sensitivity ◽  
Oxygen Uptake ◽  
Intracellular Signaling ◽  
Muscle Hypertrophy ◽  
Passive Movement ◽  
Control Group ◽  
Post Intervention ◽  
Glucose Effectiveness ◽  
Cord Injury

Abstract Background Persons with spinal cord injury (SCI) are at heightened risks of developing unfavorable cardiometabolic consequences due to physical inactivity. Functional electrical stimulation (FES) and surface neuromuscular electrical stimulation (NMES)-resistance training (RT) have emerged as effective rehabilitation methods that can exercise muscles below the level of injury and attenuate cardio-metabolic risk factors. Our aims are to determine the impact of 12 weeks of NMES+12 weeks of FES-Lower extremity cycling (LEC) compared to 12 weeks of passive movement+12 weeks of FES-LEC on 1) oxygen uptake (VO2), insulin sensitivity and glucose disposal in adults with SCI; 2) skeletal muscle size, intramuscular fat (IMF) and visceral adipose tissue (VAT) and; 3) protein expression of energy metabolism, protein molecules involved in insulin signaling, muscle hypertrophy and oxygen uptake and electron transport chain (ETC) activities. Methods/Design Forty-eight persons aged 18-65 years with chronic (> 1 year) SCI/D (AIS A-C) at the C5-L2 levels, equally sub-grouped by cervical or sub-cervical injury levels and time since injury, will be randomized into either NMES+FES group or Passive+FES (control group). The NMES+FES group will undergo 12 weeks of evoked RT using twice-weekly NMES and ankle weights followed by twice-weekly of progressive FES-LEC for an additional 12 weeks. The control group will undergo 12 weeks of passive movement followed by 12 weeks of progressive FES-LEC. Measurements will be performed at baseline (B; week 0), post-intervention 1 (P1; week 13) and post-intervention 2 (P2; week 25) and will include VO2 measurements, insulin sensitivity and glucose effectiveness using intravenous glucose tolerance test; magnetic resonance imaging to measure muscle, IMF and VAT areas; muscle biopsy to measure protein expression and intracellular signaling as well as mitochondrial ETC function. Discussion Training through NMES+RT may evoke muscle hypertrophy and positively impact oxygen uptake, insulin sensitivity and glucose effectiveness. This may result in beneficial outcomes on metabolic activity, body composition profile, mitochondrial ETC and intracellular signaling related to insulin action and muscle hypertrophy. In the future, NMES-RT may be added to FES-LEC to improve the workloads achieved in the rehabilitation of persons with SCI and further decrease muscle wasting and cardio-metabolic risks.

scholarly journals Adaptations in Mitochondrial Enzymatic Activity Occurs Independent of Genomic Dosage in Response to Aerobic Exercise Training and Deconditioning in Human Skeletal Muscle

Cells ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 237 ◽  
Author(s):  
Andreas Fritzen ◽  
Frank Thøgersen ◽  
Kasper Thybo ◽  
Christoffer Vissing ◽  
Thomas Krag ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Enzymatic Activity ◽  
Endurance Exercise ◽  
Complex I ◽  
Citrate Synthase ◽  
Knee Extensor ◽  
Mitochondrial Complex ◽  
Membrane Markers ◽  
Endurance Exercise Training

Mitochondrial DNA (mtDNA) replication is thought to be an integral part of exercise-training-induced mitochondrial adaptations. Thus, mtDNA level is often used as an index of mitochondrial adaptations in training studies. We investigated the hypothesis that endurance exercise training-induced mitochondrial enzymatic changes are independent of genomic dosage by studying mtDNA content in skeletal muscle in response to six weeks of knee-extensor exercise training followed by four weeks of deconditioning in one leg, comparing results to the contralateral untrained leg, in 10 healthy, untrained male volunteers. Findings were compared to citrate synthase activity, mitochondrial complex activities, and content of mitochondrial membrane markers (porin and cardiolipin). One-legged knee-extensor exercise increased endurance performance by 120%, which was accompanied by increases in power output and peak oxygen uptake of 49% and 33%, respectively (p < 0.01). Citrate synthase and mitochondrial respiratory chain complex I–IV activities were increased by 51% and 46–61%, respectively, in the trained leg (p < 0.001). Despite a substantial training-induced increase in mitochondrial activity of TCA and ETC enzymes, there was no change in mtDNA and mitochondrial inner and outer membrane markers (i.e. cardiolipin and porin). Conversely, deconditioning reduced endurance capacity by 41%, muscle citrate synthase activity by 32%, and mitochondrial complex I–IV activities by 29–36% (p < 0.05), without any change in mtDNA and porin and cardiolipin content in the previously trained leg. The findings demonstrate that the adaptations in mitochondrial enzymatic activity after aerobic endurance exercise training and the opposite effects of deconditioning are independent of changes in the number of mitochondrial genomes, and likely relate to changes in the rate of transcription of mtDNA.

A comparison of volume-equated knee extensions to failure, or not to failure, upon rating of perceived exertion and strength adaptations

2016 ◽  
Vol 41 (2) ◽  
pp. 168-174 ◽  
Author(s):  
James Peter Fisher ◽  
Dominic Blossom ◽  
James Steele
Keyword(s):  
Resistance Training ◽  
Perceived Exertion ◽  
Knee Extensor ◽  
Rating Of Perceived Exertion ◽  
Effect Sizes ◽  
Rest Interval ◽  
Ratings Of Perceived Exertion ◽  
Post Intervention ◽  
Training Time ◽  
Knee Extensor Strength

The present study aimed to compare the effects of repetition duration-, volume-, and load-matched resistance training to muscular failure (MMF) or not to muscular failure (NMF) on maximal voluntary isometric knee extensor strength. This design also allowed testing of the efficacy of “5×5” training. Nine recreationally active males (age, 21.4 ± 1.2 years; height, 1.79 ± 0.07 m; weight, 78.4 ± 7.1 kg) performed unilateral resistance training at 80% of maximal torque at 2×/week for 6 weeks. Using their nondominant leg, participants performed 5 sets of 5 repetitions (NMF). Using their dominant leg, participants performed 25 repetitions in as few sets as possible (MMF). All repetitions were performed at a pace of 2 s concentric, 1 s isometric pause, and 2 s eccentric with a 2-min rest interval between sets. Analyses identified significant pre- to post-intervention strength increases for both MMF and NMF, with effect sizes (ESs) of 2.01 and 1.65, respectively, with no significant differences between conditions (p > 0.05). Peak and mean ratings of perceived exertion (RPEs) were significantly higher for MMF compared with NMF conditions (p < 0.0001), and a tendency for significantly higher RPE values reported for later sets for the NMF condition. Total training time per session was significantly longer for NMF compared with MMF (p < 0.001). The present study suggests that in untrained participants, resistance training NMF produces equivocally the same strength increases as training to MMF when volume-matched. However, resistance training to MMF appears to be a more time-efficient protocol and may produce greater strength gains as indicated by a larger ES.

scholarly journals An 8-week resistance training protocol is effective in adapting quadriceps but not patellar tendon shear modulus measured by Supersonic Shearwave Imaging

2018 ◽  
Author(s):  
P. Mannarino ◽  
T. T. Matta ◽  
F. O. Oliveira
Keyword(s):  
Mechanical Properties ◽  
Resistance Training ◽  
Shear Modulus ◽  
Patellar Tendon ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Muscle Thickness ◽  
Knee Extension ◽  
Post Intervention ◽  
Training Protocol

ABSTRACTHabitual loading and resistance training (RT) can determine changes in muscle and tendon morphology but also in its mechanical properties. Conventional ultrasound (US) evaluation of these mechanical properties present limitations that can now be overcome with the advent of Supersonic Shearwave Imaging (SSI). The objective of this study was to analyze the Vastus Lateralis (VL) and patellar tendon (PT) mechanical properties adaptations to an 8-week RT protocol using SSI. We submitted 15 untrained health young men to an 8-week RT directed knee extensor mechanism. VL and PT shear modulus (μ) was assessed pre and post intervention with SSI. VL muscle thickness (VL MT) and knee extension torque (KT) was also measure pre and post intervention to ensure the RT efficiency. Significant increases were observed in VL MT and KT (pre= 2.40 ± 0.40 cm and post= 2.63 ± 0.35 cm, p = 0.0111, and pre= 294.66 ± 73.98 Nm and post= 338.93 ± 76.39 Nm, p = 0.005, respectively). The 8-week RT was also effective in promoting VL μ adaptations (pre= 4.87 ± 1.38 kPa and post= 9.08.12 ± 1.86 kPa, p = 0.0105), but not in significantly affecting PT μ (pre= 78.85 ± 7.37 kPa and post= 66.41 ± 7.25 kPa, p = 0.1287). The present study showed that an 8-week resistance training protocol was effective in adapting VL μ but not PT μ. Further investigation should be conducted with special attention to longer interventions, to possible PT differential individual responsiviness and to the muscle-tendon resting state tension environment.

scholarly journals Proton/electron stoichiometry of mitochondrial complex I estimated from the equilibrium thermodynamic force ratio

1988 ◽  
Vol 252 (2) ◽  
pp. 473-479 ◽  
Author(s):  
G C Brown ◽  
M D Brand
Keyword(s):  
Complex I ◽  
Thermodynamic Force ◽  
Protonmotive Force ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Equilibrium Thermodynamic ◽  
Isolated Mitochondria ◽  
Force Ratio ◽  
Thermodynamic Forces ◽  
Mitochondrial Complexes

The thermodynamic forces on electrons (delta Eh) and protons (delta p) across mitochondrial complexes I, III and IV were measured in isolated mitochondria respiring on succinate. The force ratio (delta Eh/delta p) across complex I close to equilibrium was found to be about 2. The equilibrium force ratio across complex I was measured during sulphite oxidation and was again close to 2. These results indicate that the proton/electron stoichiometry of complex I is 2, in conditions of high protonmotive force.

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