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Walluks K, Hoffmann B, Svensson CM, Förster G, Müller AH, Jarvis J, Perkins J, Figge MT, Arnold D. Long-term stimulation by implanted pacemaker enables non-atrophic treatment of bilateral vocal fold paresis in a human-like animal model. Sci Rep 2024; 14:10440. [PMID: 38714750 PMCID: PMC11076618 DOI: 10.1038/s41598-024-60875-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/29/2024] [Indexed: 05/10/2024] Open
Abstract
A wide variety of treatments have been developed to improve respiratory function and quality of life in patients with bilateral vocal fold paresis (BVFP). One experimental method is the electrical activation of the posterior cricoarytenoid (PCA) muscle with a laryngeal pacemaker (LP) to open the vocal folds. We used an ovine (sheep) model of unilateral VFP to study the long-term effects of functional electrical stimulation on the PCA muscles. The left recurrent laryngeal nerve was cryo-damaged in all animals and an LP was implanted except for the controls. After a reinnervation phase of six months, animals were pooled into groups that received either no treatment, implantation of an LP only, or implantation of an LP and six months of stimulation with different duty cycles. Automated image analysis of fluorescently stained PCA cross-sections was performed to assess relevant muscle characteristics. We observed a fast-to-slow fibre type shift in response to nerve damage and stimulation, but no complete conversion to a slow-twitch-muscle. Fibre size, proportion of hybrid fibres, and intramuscular collagen content were not substantially altered by the stimulation. These results demonstrate that 30 Hz burst stimulation with duty cycles of 40% and 70% did not induce PCA atrophy or fibrosis. Thus, long-term stimulation with an LP is a promising approach for treating BVFP in humans without compromising muscle conditions.
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Affiliation(s)
- Kassandra Walluks
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Jena, Germany
- Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
- Institute of Zoology and Evolutionary Research, Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
| | - Bianca Hoffmann
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Jena, Germany
| | - Carl-Magnus Svensson
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Jena, Germany
| | - Gerhard Förster
- Clinic for Otorhinolaryngology/Plastic Surgery, Wald-Klinikum Gera, Gera, Germany
| | - Andreas H Müller
- Clinic for Otorhinolaryngology/Plastic Surgery, Wald-Klinikum Gera, Gera, Germany
| | - Jonathan Jarvis
- Faculty of Science, Sport and Exercise Sciences, John Moores University, Liverpool, UK
| | | | - Marc Thilo Figge
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Jena, Germany.
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany.
| | - Dirk Arnold
- Clinic and Polyclinic for Otorhinolaryngology, University Hospital Jena, Jena, Germany.
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Krause A, da Mota de Moreira I, Walser N, Memmert D, Ritzmann R. Whole-Body Electromyostimulation Impacts Physiological Responses During Aerobic Running: A Randomized Trial. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2023; 94:1133-1140. [PMID: 36624960 DOI: 10.1080/02701367.2022.2120949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 08/30/2022] [Indexed: 06/17/2023]
Abstract
Objective: The aim of the current study was to evaluate the physiological and metabolic responses to running with whole-body electromyostimulation (wbEMS) compared to running without electromyostimulation (control, CG). Methods: Twenty healthy participants (9 male/11 female, age 42 ±7 years) conducted an incremental step test with respiratory gas analysis until exhaustion. Trials were conducted as wbEMS and CG in a random order. As outcome measures, (A) objective total exhaustion, (B) athletic responses (max. time and velocity) and (C) physiological and metabolic responses (V'O2/ kg, V'E, EE, RER, lactate) were compared. (D) The impact on the skeletal muscle was assessed prior, 48 h & 72 h after trial. Results: During both trials, participants (A) ran until total exhaustion. Nonetheless, (B) time and velocity till exhaustion as well as (C) RER prior to the first lactate threshold and V'E were reduced with wbEMS. All other correlates did not differ significantly between wbEMS and CG. Following 48 h and 72 h after the trial with wbEMS, (D) the impact on the skeletal muscle was 7- to 9-fold higher compared to baseline values. Values differed significantly to those after running without wbEMS. Conclusion: With the additional stimulation during voluntary activation, wbEMS induces earlier fatigue and a shift in energy metabolism toward fat utilization. Even during aerobic endurance tasks, a great impact on the skeletal muscle indicated by the rise in CK could be observed which promotes wbEMS as an alternative training stimulus that is easy-to-apply and effective during endurance training.
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Alharbi A, Li J, Womack E, Farrow M, Yarar-Fisher C. The Effect of Lower Limb Combined Neuromuscular Electrical Stimulation on Skeletal Muscle Signaling for Glucose Utilization, Myofiber Distribution, and Metabolic Function after Spinal Cord Injury. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6958. [PMID: 37887696 PMCID: PMC10606374 DOI: 10.3390/ijerph20206958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/29/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023]
Abstract
Maintaining healthy myofiber type and metabolic function early after spinal cord injury (SCI) may prevent chronic metabolic disorders. This study compares the effects of a 2-5 week combined (aerobic + resistance) neuromuscular electrical stimulation (Comb-NMES) regimen versus a sham control treatment on muscle protein signaling for glucose uptake, myofiber type distribution, and metabolic function. Twenty participants (31 ± 9 years of age) with an SCI (C4-L1, AIS level A-C) within 14 days of the SCI were randomly assigned to control (N = 8) or Comb-NMES (N = 12). Sessions were given three times per week. Fasting blood samples and vastus lateralis muscle biopsies were collected 24-48 h before or after the last session. Western blots were performed to quantify proteins, immunohistochemical analyses determined muscle myofiber distribution, and enzymatic assays were performed to measure serum glucose, insulin, and lipids. Our main findings include a decrease in fasting glucose (p < 0.05) and LDL-C (p < 0.05) levels, an upregulation of CamKII and Hexokinase (p < 0.05), and an increase in type I (+9%) and a decrease in type IIx (-36%) myofiber distribution in response to Comb-NMES. Our findings suggest that maintaining healthy myofiber type and metabolic function may be achieved via early utilization of Comb-NMES.
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Affiliation(s)
- Amal Alharbi
- Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL 35233, USA;
| | - Jia Li
- Department of Physical Medicine and Rehabilitation, Ohio State University, Columbus, OH 43210, USA; (J.L.); (M.F.)
| | - Erika Womack
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Starkville, MS 39762, USA;
| | - Matthew Farrow
- Department of Physical Medicine and Rehabilitation, Ohio State University, Columbus, OH 43210, USA; (J.L.); (M.F.)
| | - Ceren Yarar-Fisher
- Department of Physical Medicine and Rehabilitation, Ohio State University, Columbus, OH 43210, USA; (J.L.); (M.F.)
- Department of Neuroscience, Ohio State University, Columbus, OH 43210, USA
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Chu XL, Song XZ, Li Q, Li YR, He F, Gu XS, Ming D. Basic mechanisms of peripheral nerve injury and treatment via electrical stimulation. Neural Regen Res 2022; 17:2185-2193. [PMID: 35259827 PMCID: PMC9083151 DOI: 10.4103/1673-5374.335823] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Previous studies on the mechanisms of peripheral nerve injury (PNI) have mainly focused on the pathophysiological changes within a single injury site. However, recent studies have indicated that within the central nervous system, PNI can lead to changes in both injury sites and target organs at the cellular and molecular levels. Therefore, the basic mechanisms of PNI have not been comprehensively understood. Although electrical stimulation was found to promote axonal regeneration and functional rehabilitation after PNI, as well as to alleviate neuropathic pain, the specific mechanisms of successful PNI treatment are unclear. We summarize and discuss the basic mechanisms of PNI and of treatment via electrical stimulation. After PNI, activity in the central nervous system (spinal cord) is altered, which can limit regeneration of the damaged nerve. For example, cell apoptosis and synaptic stripping in the anterior horn of the spinal cord can reduce the speed of nerve regeneration. The pathological changes in the posterior horn of the spinal cord can modulate sensory abnormalities after PNI. This can be observed in cases of ectopic discharge of the dorsal root ganglion leading to increased pain signal transmission. The injured site of the peripheral nerve is also an important factor affecting post-PNI repair. After PNI, the proximal end of the injured site sends out axial buds to innervate both the skin and muscle at the injury site. A slow speed of axon regeneration leads to low nerve regeneration. Therefore, it can take a long time for the proximal nerve to reinnervate the skin and muscle at the injured site. From the perspective of target organs, long-term denervation can cause atrophy of the corresponding skeletal muscle, which leads to abnormal sensory perception and hyperalgesia, and finally, the loss of target organ function. The mechanisms underlying the use of electrical stimulation to treat PNI include the inhibition of synaptic stripping, addressing the excessive excitability of the dorsal root ganglion, alleviating neuropathic pain, improving neurological function, and accelerating nerve regeneration. Electrical stimulation of target organs can reduce the atrophy of denervated skeletal muscle and promote the recovery of sensory function. Findings from the included studies confirm that after PNI, a series of physiological and pathological changes occur in the spinal cord, injury site, and target organs, leading to dysfunction. Electrical stimulation may address the pathophysiological changes mentioned above, thus promoting nerve regeneration and ameliorating dysfunction.
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Affiliation(s)
- Xiao-Lei Chu
- Academy of Medical Engineering and Translational Medicine, Tianjin University; Department of Rehabilitation, Tianjin Hospital, Tianjin, China
| | - Xi-Zi Song
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | - Qi Li
- Academy of Medical Engineering and Translational Medicine, Tianjin University; Department of Rehabilitation, Tianjin Hospital, Tianjin, China
| | - Yu-Ru Li
- College of Exercise & Health Sciences, Tianjin University of Sport, Tianjin, China
| | - Feng He
- College of Precision Instruments & Optoelectronics Engineering, Tianjin University, Tianjin, China
| | - Xiao-Song Gu
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | - Dong Ming
- Academy of Medical Engineering and Translational Medicine; College of Precision Instruments & Optoelectronics Engineering, Tianjin University, Tianjin, China
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Cardiorespiratory, Metabolic and Perceived Responses to Electrical Stimulation of Upper-Body Muscles While Performing Arm Cycling. J Hum Kinet 2021; 77:117-123. [PMID: 34168697 PMCID: PMC8008305 DOI: 10.2478/hukin-2021-0016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study was designed to assess systemic cardio-respiratory, metabolic and perceived responses to incremental arm cycling with concurrent electrical myostimulation (EMS). Eleven participants (24 ± 3 yrs; 182 ± 10 cm; 86 ± 16.8 kg) performed two incremental tests involving arm cycling until volitional exhaustion was reached with and without EMS of upper-body muscles. The peak power output was 10.1% lower during arm cycling with (128 ± 30 W) than without EMS (141 ± 25 W, p = 0.01; d = 0.47). In addition, the heart rate (2-9%), oxygen uptake (7-15%), blood lactate concentration (8-46%) and ratings of perceived exertion (4-14%) while performing submaximal arm cycling with EMS were all higher with than without EMS (all p < 0.05). Upon exhaustion, the heart rate, oxygen uptake, lactate concentration, and ratings of perceived exertion did not differ between the two conditions (all p > 0.05). In conclusion, arm cycling with EMS induced more pronounced cardio-respiratory, metabolic and perceived responses, especially during submaximal arm cycling. This form of exercise with stimulation might be beneficial for a variety of athletes competing in sports involving considerable generation of work by the upper body (e.g., kayaking, cross-country skiing, swimming, rowing and various parasports).
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Salmons S. The adaptive response of skeletal muscle: What is the evidence? Muscle Nerve 2017; 57:531-541. [PMID: 28857207 DOI: 10.1002/mus.25949] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 08/05/2017] [Accepted: 08/25/2017] [Indexed: 11/08/2022]
Abstract
Adult skeletal muscle is capable of adapting its properties in response to changing functional demands. This now sounds like a statement of the obvious, and many people assume it has always been this way. A mere 40 years ago, however, the picture was entirely different. In this Review and personal memoir, I outline the scientific context in which the theory was generated, the objections to it from entrenched opinion, and the way those objections were progressively met. The material should be of some historical interest, but, more importantly, it collects together the full range of evidence on which the current paradigm is based. Muscle Nerve 57: 531-541, 2018.
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Affiliation(s)
- Stanley Salmons
- Department of Musculoskeletal Biology, Institute of Ageing & Chronic Diseases, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool, L7 8TX, United Kingdom
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Vickerton P, Jarvis JC, Gallagher JA, Akhtar R, Sutherland H, Jeffery N. Morphological and histological adaptation of muscle and bone to loading induced by repetitive activation of muscle. Proc Biol Sci 2014; 281:20140786. [PMID: 24966314 PMCID: PMC4083794 DOI: 10.1098/rspb.2014.0786] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 06/03/2014] [Indexed: 01/06/2023] Open
Abstract
Muscular contraction plays a pivotal role in the mechanical environment of bone, but controlled muscular contractions are rarely used to study the response of bone to mechanical stimuli. Here, we use implantable stimulators to elicit programmed contractions of the rat tibialis anterior (TA) muscle. Miniature stimulators were implanted in Wistar rats (n = 9) to induce contraction of the left TA every 30 s for 28 days. The right limb was used as a contralateral control. Hindlimbs were imaged using microCT. Image data were used for bone measurements, and to construct a finite-element (FE) model simulation of TA forces propagating through the bone. This simulation was used to target subsequent bone histology and measurement of micromechanical properties to areas of high strain. FE mapping of simulated strains revealed peak values in the anterodistal region of the tibia (640 µε ± 30.4 µε). This region showed significant increases in cross-sectional area (28.61%, p < 0.05) and bone volume (30.29%, p < 0.05) in the stimulated limb. Histology revealed a large region of new bone, containing clusters of chondrocytes, indicative of endochondral ossification. The new bone region had a lower elastic modulus (8.8 ± 2.2 GPa) when compared with established bone (20 ± 1.4 GPa). Our study provides compelling new evidence of the interplay between muscle and bone.
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Affiliation(s)
- Paula Vickerton
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Jonathan C Jarvis
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Merseyside, Liverpool L3 3AF, UK
| | - James A Gallagher
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Riaz Akhtar
- Centre for Materials and Structures, School of Engineering, University of Liverpool, Merseyside, Liverpool L69 3GH, UK
| | - Hazel Sutherland
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Merseyside, Liverpool L3 3AF, UK
| | - Nathan Jeffery
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
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Willand MP, Holmes M, Bain JR, Fahnestock M, De Bruin H. Electrical muscle stimulation after immediate nerve repair reduces muscle atrophy without affecting reinnervation. Muscle Nerve 2013; 48:219-25. [PMID: 23637030 DOI: 10.1002/mus.23726] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2012] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Electrical stimulation of denervated muscle has been shown to minimize atrophy and fibrosis and increase force in animal and human models. However, electrical stimulation after nerve repair is controversial due to questions of efficacy. METHODS Using a rat model, we investigated the efficacy of short-term electrical muscle stimulation for increasing reinnervation and preventing muscle atrophy. After tibial nerve transection and immediate repair with the fibular nerve, 1 month of electrical stimulation was applied 5 days/week for 1 hour to the gastrocnemius muscle via implanted electrodes. RESULTS After 2 months of further recovery without stimulation, muscle weights, twitch forces, and type I fiber areas were significantly greater in stimulated animals than in repaired controls without stimulation. Motor unit size and numbers were not different between the 2 groups. CONCLUSIONS Short-term electrical muscle stimulation after nerve repair significantly reduces muscle atrophy and does not affect motor reinnervation.
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Affiliation(s)
- Michael P Willand
- School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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Green HJ, Burnett M, Carter S, Jacobs I, Ranney D, Smith I, Tupling S. Role of exercise duration on metabolic adaptations in working muscle to short-term moderate-to-heavy aerobic-based cycle training. Eur J Appl Physiol 2013; 113:1965-78. [PMID: 23543067 DOI: 10.1007/s00421-013-2621-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 02/27/2013] [Indexed: 12/29/2022]
Abstract
This study aimed at investigating the relative roles of the duration versus intensity of exercise on the metabolic adaptations in vastus lateralis to short-term (10 day) aerobic-based cycle training. Healthy males with a peak aerobic power (VO2 peak) of 46.0 ± 2.0 ml kg(-1) min(-1) were assigned to either a 30-min (n = 7) or a 60-min (n = 8) duration performed at two different intensities (with order randomly assigned), namely moderate (M) and heavy (H), corresponding to 70 and 86 % VO2 peak, respectively. No change (P > 0.05) in VO2 peak was observed regardless of the training program. Based on the metabolic responses to prolonged exercise (60 % VO2 peak), both M and H and 30 and 60 min protocols displayed less of a decrease (P < 0.05) in phosphocreatine (PCr) and glycogen (Glyc) and less of an increase (P < 0.05) in free adenosine diphosphate (ADPf), free adenosine monophosphate (AMPf), inosine monophosphate (IMP) and lactate (La). Training for 60 min compared with 30 min resulted in a greater protection (P < 0.05) of ADPf, AMPf, PCr and Glyc during exercise, effects that were not displayed between M and H. The reduction in both VO2 and RER (P < 0.05) observed during submaximal exercise did not depend on training program specifics. These findings indicate that in conjunction with our earlier study (Green et al., Eur J Appl Physiol, 2012b), a threshold exists for duration rather than intensity of aerobic exercise to induce a greater training impact in reducing metabolic strain.
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Affiliation(s)
- Howard J Green
- Department of Kinesiology, University of Waterloo, Waterloo, ON , N2L3G1, Canada.
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Wahl P, Schaerk J, Achtzehn S, Kleinöder H, Bloch W, Mester J. Physiological responses and perceived exertion during cycling with superimposed electromyostimulation. J Strength Cond Res 2013; 26:2383-8. [PMID: 22067251 DOI: 10.1519/jsc.0b013e31823f2749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The goal of the study was to evaluate and to quantify the effects of local electromyostimulation (EMS) during cycling on the cardiorespiratory system, muscle metabolism, and perceived exertion compared with cycling with no EMS. Ten healthy men (age: 24.6 ± 3.2 years, V[Combining Dot Above]O2max: 54.1 ± 6.0 ml·min·kg) performed 3 incremental cycle ergometer step tests, 1 without and 2 with EMS (30 and 85 Hz) until volitional exhaustion. Lactate values and respiratory exchange ratio were significantly higher at intensities ≥75% peak power output (PPO) when EMS was applied. Bicarbonate concentration, base excess (BE), and Pco2 were significantly lower when EMS was applied compared with the control at intensities ≥75% PPO. Saliva cortisol levels increased because of the exercise but were unaffected by EMS. Furthermore, EMS showed greater effects on CK levels 24 hours postexercise than normal cycling did. Rating of perceived exertion was significantly higher at 100% PPO with EMS. No statistical differences were found for heart rate, pH, and Po2 between the tested cycling modes. The main findings of this study are greater metabolic changes (lactate, respiratory exchange ratio, BE, (Equation is included in full-text article.), Pco2) during cycling with EMS compared with normal cycling independent of frequency, mainly visible at higher work rates. Because metabolic alterations are important for the induction of cellular signaling cascades and adaptations, these results lead to the hypothesis that applied EMS stimulations during cycling exercise might be an enhancing stimulus for skeletal muscle metabolism and related adaptations. Thus, superimposed EMS application during cycling could be beneficial to aerobic performance enhancements in athletes and in patients who cannot perform high workloads. However, the higher demand on skeletal muscles involved must be considered.
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Affiliation(s)
- Patrick Wahl
- Institute of Training Science and Sport Informatics, German Sport University, Cologne, Germany.
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Zaidi FN, Meadows P, Jacobowitz O, Davidson TM. Tongue anatomy and physiology, the scientific basis for a novel targeted neurostimulation system designed for the treatment of obstructive sleep apnea. Neuromodulation 2012; 16:376-86; discussion 386. [PMID: 22938390 DOI: 10.1111/j.1525-1403.2012.00514.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Obstructive sleep apnea (OSA) is a chronic condition that affects millions adults. The effective standard treatment is positive airway pressure (PAP). However, approximately half of the patients that are prescribed PAP are unable or unwilling to comply with this therapy. Untreated OSA ultimately leads to very serious comorbidities. An alternative therapy for this patient population, therefore, is desirable. Hypoglossal nerve (HGN) stimulation is under investigation by multiple groups as a possible alternative therapy for OSA. OBJECTIVE To understand the underlying mechanisms of actions related to HGN stimulation, and the implication of this knowledge for specifying and designing a neurostimulation system for the treatment of OSA. RESULTS Loss of lingual and pharyngeal tone within a narrow airway is the primary mechanism for OSA. Posterior and anterior tongues are different in their anatomy and physiology. Muscle fibers in the posterior tongue are predominantly fatigue resistant that are responsible for the long sustained tonic activities required for maintaining the tongue's position and preventing its mass from falling into the retroglossal airway. The human tongue is a muscular hydrostat and hence would benefit from a sophisticated HGN stimulation system that is capable of achieving a concerted spatio-temporal interplay of multiple lingual muscles, including retrusors. CONCLUSION Targeted neurostimulation of the proximal HGN presents as a viable system approach that is far more versatile and physiologic and quite different than prior systems.
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Affiliation(s)
- Faisal N Zaidi
- Imthera Medical, Inc., San Diego, CA, USA. Hudson Valley Ear, Nose & Throat PC, Middletown, NY, USA. New York Presbyterian Hospital/Columbia University and Attending, Mount Sinai Medical Center and Sleep Surgery and Sleep Medicine, New York, NY, USA. Head & Neck Surgery Clinic, UCSD Hillcrest-Medical Offices North, University of California San Diego, San Diego, CA, USA
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Green HJ, Burnett M, Kollias H, Ouyang J, Smith I, Tupling S. Can increases in capillarization explain the early adaptations in metabolic regulation in human muscle to short-term training? Can J Physiol Pharmacol 2012; 90:557-66. [DOI: 10.1139/y2012-013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To investigate the hypothesis that increases in fibre capillary density would precede increases in oxidative potential following training onset, tissue was extracted from the vastus lateralis prior to (0 days) and following 3 and 6 consecutive days of submaximal cycle exercise (2 h·day–1). Participants were untrained males (age = 21.4 ± 0.58 years; peak oxygen consumption = 46.2 ± 1.6 mL·kg–1·min–1; mean ± standard error (SE)). Tissue was assessed for succinic dehydrogenase activity (SDH) by microphotometry and indices of capillarization based on histochemically assessed area and capillary counts (CC) in specific fibre types. Three days of training (n = 13) resulted in a generalized decrease (p < 0.05) in fibre area (–14.2% ± 3.0%; mean ± SE) and increase (p < 0.05) in CC/Area (20.4% ± 2.7%) and no change in either CC or SDH activity. Following 6 days of treatment (n = 6), increases (p < 0.05) in CC (18.2% ± 4.2%), CC/Area (28.9% ± 3.2%), and SDH activity (22.9% ± 6.0%) occurred that was not specific to major fibre type. No changes in either fibre area or fibre-type distribution were observed with additional training. We conclude that increases in angiogenic-based capillary density and oxidative potential occur coincidentally following training onset, while increases in capillary density, mediated by reductions in fibre area, represent an initial isolated response, the significance of which may be linked to the metabolic alterations that also result.
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Affiliation(s)
- Howard J. Green
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Margaret Burnett
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Helen Kollias
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Jing Ouyang
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Ian Smith
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Susan Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Normann RA, Dowden BR, Frankel MA, Wilder AM, Hiatt SD, Ledbetter NM, Warren DA, Clark GA. Coordinated, multi-joint, fatigue-resistant feline stance produced with intrafascicular hind limb nerve stimulation. J Neural Eng 2012; 9:026019. [PMID: 22414699 DOI: 10.1088/1741-2560/9/2/026019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The production of graceful skeletal movements requires coordinated activation of multiple muscles that produce torques around multiple joints. The work described herein is focused on one such movement, stance, that requires coordinated activation of extensor muscles acting around the hip, knee and ankle joints. The forces evoked in these muscles by external stimulation all have a complex dependence on muscle length and shortening velocities, and some of these muscles are biarticular. In order to recreate sit-to-stand maneuvers in the anesthetized feline, we excited the hind limb musculature using intrafascicular multielectrode stimulation (IFMS) of the muscular branch of the sciatic nerve, the femoral nerve and the main branch of the sciatic nerve. Stimulation was achieved with either acutely or chronically implanted Utah Slanted Electrode Arrays (USEAs) via subsets of electrodes (1) that activated motor units in the extensor muscles of the hip, knee and ankle joints, (2) that were able to evoke large extension forces and (3) that manifested minimal coactivation of the targeted motor units. Three hind limb force-generation strategies were investigated, including sequential activation of independent motor units to increase force, and interleaved or simultaneous IFMS of three sets of six or more USEA electrodes that excited the hip, knee and ankle extensors. All force-generation strategies evoked stance, but the interleaved IFMS strategy also reduced muscle fatigue produced by repeated sit-to-stand maneuvers compared with fatigue produced by simultaneous activation of different motor neuron pools. These results demonstrate the use of interleaved IFMS as a means to recreate coordinated, fatigue-resistant multi-joint muscle forces in the unilateral hind limb. This muscle activation paradigm could provide a promising neuroprosthetic approach for the restoration of sit-to-stand transitions in individuals who are paralyzed by spinal cord injury, stroke or disease.
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Affiliation(s)
- R A Normann
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA.
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Bergh A, Nordlöf H, Essén-Gustavsson B. Evaluation of neuromuscular electrical stimulation on fibre characteristics and oxidative capacity in equine skeletal muscles. Equine Vet J 2011:671-5. [PMID: 21059079 DOI: 10.1111/j.2042-3306.2010.00180.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
REASONS FOR PERFORMING STUDY Neuromuscular electrical stimulation (NMES) is used to increase or maintain muscle strength during rehabilitation. Human studies investigating different protocols show that some treatments induce changes in muscle characteristics. Despite the frequent use of NMES in horses, no studies have been published describing its efficacy. OBJECTIVES To investigate the effects of a NMES protocol on equine fibre types and areas, glycogen concentrations and enzyme activities. METHODS NMES was administrated to m. gluteus medius and m. longissimus dorsi, on one side of 6 healthy Standardbred horses. The contralateral side of each muscle served as a nonstimulated control. The horses were stimulated at 50 Hz a day, with 21-39 mA, for 45-60 min, 5 days a week for 4 weeks. Needle biopsies were obtained from the muscles on both sides before and after the experimental period. Muscle samples were analysed for fibre type proportions and area using histochemical methods and for glycogen and enzyme activities (citrate synthase, 3-OH-acyl CoA dehydrogenase, hexokinase and lactate dehydrogenase) using biochemical methods. Muscle contractions at the location and depth of the muscle biopsy were confirmed by diagnostic ultrasound. Nonparametric tests (Mann-Whitney, Wilcoxon sign-rank) were used for statistical analysis. RESULTS No significant differences were observed in the percentage of types I, IIA or IIX fibres, fibre areas, glycogen levels or enzyme activities either when comparing stimulated and nonstimulated muscles before and after the NMES treatment, or when comparing the left and right muscle samples. CONCLUSIONS The NMES treatment was well tolerated by the horses, but the present protocol did not induce significant muscle adaptations. Further studies are needed to describe the effect of more intense and/or prolonged NMES treatment protocols on muscles of healthy horses, and to describe if stimulation protocols induce positive changes in atrophied muscles.
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Affiliation(s)
- A Bergh
- Department of Anatomy, Swedish University of Agricultural Sciences, Sweden.
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15
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Duffell LD, Rowlerson AM, Donaldson NDN, Harridge SDR, Newham DJ. Effects of endurance and strength-directed electrical stimulation training on the performance and histological properties of paralyzed human muscle: a pilot study. Muscle Nerve 2010; 42:756-63. [PMID: 20976779 DOI: 10.1002/mus.21746] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Electrical stimulation (ES) improves muscle properties after spinal cord injury (SCI), but cycling power output (PO) remains low. We investigated the effect of endurance and strength ES training on these parameters. Assessments of quadriceps strength and fatigue resistance, cycling PO, and muscle biopsies were made in four well-trained SCI subjects (three cyclists and one rower) before and after additional weight training in the cyclists and once in the rower. Weight training improved muscle strength, but cycling PO was low in all subjects. There was no effect of training type on biopsy data. Biopsies showed non-specific signs of pathology, predominance of type IIa fibers, and uniform metabolic activity. Oxidative activity was low, as were capillary:fiber ratios in the cyclists. Cycling PO is limited by factors other than muscle strength. Future ES training studies should attempt to improve muscle oxidative capacity to optimize the potential benefits of ES exercise.
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Affiliation(s)
- Lynsey D Duffell
- Division of Applied Biomedical Research, King's College London, London, UK
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Changes in contractile properties of skinned single rat soleus and diaphragm fibres after chronic hypoxia. Pflugers Arch 2010; 460:863-73. [PMID: 20697736 DOI: 10.1007/s00424-010-0866-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/08/2010] [Accepted: 07/20/2010] [Indexed: 01/03/2023]
Abstract
Hypoxia may be one of the factors underlying muscle dysfunction during ageing and chronic lung and heart failure. Here we tested the hypothesis that chronic hypoxia per se affects contractile properties of single fibres of the soleus and diaphragm muscle. To do this, the force-velocity relationship, rate of force redevelopment and calcium sensitivity of single skinned fibres from normoxic rats and rats exposed to 4 weeks of hypobaric hypoxia (410 mmHg) were investigated. The reduction in maximal force (P(0)) after hypoxia (p=0.031) was more pronounced in type IIa than type I fibres and was mainly attributable to a reduction in fibre cross-sectional area (p=0.044). In type IIa fibres this was aggravated by a reduction in specific tension (p=0.001). The maximal velocity of shortening (V (max)) and shape of the force velocity relation (a/P(0)), however, did not differ between normoxic and hypoxic muscle fibres and the reduction in maximal power of hypoxic fibres (p=0.012) was mainly due to a reduction in P(0). In conclusion, chronic hypoxia causes muscle fibre dysfunction which is not only due to a loss of muscle mass, but also to a diminished force generating capacity of the remaining contractile material. These effects are similar in the soleus and diaphragm muscle, but more pronounced in type IIa than I fibres.
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Salmons S. An interesting study of the relationship between electromyographic activity in jaw muscles and their fibre type composition. J Anat 2010; 216:417; author reply 417. [PMID: 20447250 DOI: 10.1111/j.1469-7580.2009.01206_1.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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