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Neuromuscular electrical stimulation (NMES) is widely used for improving muscle strength, preventing muscle atrophy, and decreasing pain. Recently, NMES has become a substitute for exercise therapy for metabolism improvement and functional capacity improvement. However, NMES has several disadvantages. First, slow-twitch muscle contractions are insufficient because the recruitment pattern of NMES does not obey Henneman's size principle. Second, when using surface electrodes, it is difficult to contract deep skeletal muscles at the application site. Third, electrical stimulation causes discomfort. Therefore, we devised a simultaneous combination of NMES and voluntary muscle contractions to overcome the weak points of NMES. A hybrid training system (HTS) that resists the motion of a volitionally contracting agonist muscle with force generated by its electrically stimulated antagonist was developed as a technique to combine the application of NMES and volitional contractions. This motion sensor makes it possible to simultaneously combine voluntary movements with NMES. Our HTS synchronizes with voluntary movements, enhancing safety and reducing discomfort. This HTS enhances the exercise effect of even simple exercise. So far, our HTS has been reported to be effective for muscle strength enhancement, prevention of muscle atrophy, improvement of physical function, pain relief, enhancement of physical fitness, and improvement of metabolic function. HTS are expected to be useful methods in environments where sufficient exercise load is not available or for individuals with low exercise tolerance.
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A hybrid training system (HTS) combining antagonist muscle electrical stimulation and voluntary muscle contraction has been developed using eccentric antagonist muscle contractions with electrical stimulation as resistance to voluntary muscle contractions. We devised an exercise method using HTS combined with a cycle ergometer (HCE). The purpose of this study was to compare the muscle strength, muscle volume, aerobic functions and lactate metabolism of HCE and a volitional cycle ergometer (VCE). A total of 14 male participants performed exercise on a bicycle ergometer for 30 min per session, 3 times per week for 6 weeks. We divided 14 participants into an HCE group (7 participants) and a VCE group (7 participants). The workload was set at 40% of each participant's peak oxygen uptake (V.O2peak). Electrodes were placed over each motor point on the quadriceps and hamstrings. The V.O2peak and anaerobic threshold significantly increased before and after training when using HCE rather than VCE. The HCE group had significantly increased extension and flexion muscle strength at 180 degrees/s in post-training measurements over pre-training measurements. Knee flexion muscle strength at 180 degrees/s tended to increase in the HCE group compared to the VCE group. The quadricep muscle cross-sectional area was significantly increased in the HCE group compared to the VCE group. Additionally, the HCE group had significantly decreased maximal lactate, measured every 5 min during exercise at the end of study, between pre and post-training. Thus, HCE may be a more effective training method for muscle strength, muscle mass and aerobic functions at 40% of each participant's V.O2peak than conventional cycling exercise. HCE could be applied not only as aerobic exercise but also as resistance training.
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ABSTRACT: Hashida, R, Takano, Y, Matsuse, H, Kudo, M, Bekki, M, Omoto, M, Nago, T, Kawaguchi, T, Torimura, T, and Shiba, N. Electrical stimulation of the antagonist muscle during cycling exercise interval training improves oxygen uptake and muscle strength. J Strength Cond Res 35(1): 111-117, 2021-A hybrid training system (HTS) is a resistance exercise method that combines voluntary concentric muscle contractions and electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on cycle ergometer (HCE). The purpose of this study was to compare cardiorespiratory function and muscle strength when cycling exercise is combined with electrical stimulation over an extended period. Twenty-nine healthy young men were divided into an HCE group (n = 14) and a volitional cycle ergometer (VCE alone) group (n = 15). All subjects performed 30-minute cycling exercise interval training sessions 3 times a week for 6 weeks. The VÌo2peak of both groups significantly increased compared with the pretraining period (HCE group: from 31.3 ± 4.4 [ml·kg-1·min-1] pretraining to 37.6 ± 6.7 [ml·kg-1·min-1] post-training [p = 0.0024] and VCE group: from 34.0 ± 7.1 [ml·kg-1·min-1] pretraining to 38.4 ± 8.2 [ml·kg-1·min-1] [p = 0.0057]). After the training, there was no significant difference of changes in VÌo2peak between the HCE and the VCE groups (p = 0.7107). In the VCE group, the maximal isokinetic torque of knee extension (60°·s-1) post-training did not significantly increase compared with the pretraining period (VCE group: from 2.4 ± 0.5 [N·m·kg-1] pretraining to 2.5 ± 0.4 [N·m·kg-1] [p = 0.4543]). By contrast, in the HCE group, the maximal isokinetic torque of knee extension (60°·s-1) post-training significantly increased compared with pretraining period (HCE group: from 2.5 ± 0.3 [N·m·kg-1] pretraining to 2.8 ± 0.3 [N·m·kg-1] [p < 0.0001]). The change in knee extension torque was significantly greater for the HCE group than for the VCE group (p = 0.0307). In conclusion, cardiopulmonary function and knee extension strength were improved by the use of HCE.
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Ejercicio Físico , Fuerza Muscular , Estimulación Eléctrica , Humanos , Masculino , Contracción Muscular , Músculo Esquelético , Músculos , Oxígeno , TorqueRESUMEN
Insulin resistance is associated with the progression of nonalcoholic fatty liver disease (NAFLD). Insulin resistance is regulated by various cytokines, including interleukin-6 (IL-6), a proinflammatory myokine, and selenoprotein P (SeP), a liver-derived secretory hepatokine. High levels of IL-6 and/or SeP have been shown to contribute to insulin resistance, and exercise is a first-line therapy for NAFLD. We have developed a hybrid training system (HTS): a neuromuscular electrical stimulation device to enhance exercise results. We aimed to investigate the effects of HTS on insulin resistance as well as serum IL-6 and SeP in patients with NAFLD. This is a randomized, single-blind (assessor), controlled trial. Subjects with NAFLD walked on a treadmill with or without HTS (9 subjects each) for 30 minutes three times a week for six weeks (HTS vs. control group; median age 45 vs. 45; male/female 5/4 vs. 6/3). We examined subjects before the first session and at the end of the final session. Serum SeP levels were measured by ELISA which measures the fragment of SeP. In the HTS group, HOMA-IR values were significantly reduced compared to the control group (Δ-0.71 vs. Δ0.05; P < 0.05). IL-6 and SeP levels in serum were also significantly reduced compared to that of the control group (IL-6; Δ-0.6 vs. Δ0.29 pg/mL; P < 0.05, SeP; Δ-1288.5 vs. Δ-435.4 ng/mL; P < 0.05, respectively). In conclusion, we propose that HTS improves insulin resistance by reducing serum IL-6 and SeP levels in patients with NAFLD.
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Resistencia a la Insulina , Enfermedad del Hígado Graso no Alcohólico/terapia , Adulto , Alanina Transaminasa/sangre , Biomarcadores/sangre , Peso Corporal , Femenino , Humanos , Grasa Intraabdominal/patología , Masculino , Persona de Mediana Edad , Enfermedad del Hígado Graso no Alcohólico/sangre , Enfermedad del Hígado Graso no Alcohólico/patología , Cooperación del Paciente , Proyectos PilotoRESUMEN
The SEM Glove developed by Bioservo Technologies AB is a new device that increases grip and pinch force. The purpose of this study was to evaluate the effectiveness of the device on the grip and pinch strength of patients with functional disorders of the fingers. MATERIALS AND METHOD: 30 hospitalized patients with upper limb functional disorder were enrolled. The assistance of the device for the grip and pinch strength of each subject were assessed by the difference between the measured values with and without the SEM Glove. The 95% confidence interval of the difference was calculated across the subjects, and statistical significance was defined as when the lower limit was a positive value (corresponding with a paired t-test at a significance level of 0.05). The odds ratio was calculated in the study of subject adaptation, with statistical significance set using Fisher's exact test at a significance level of 0.05. RESULTS: Grip strength significantly decreased (worn-not worn difference (kg): mean = -3.7, CI95 (-5.4, -2.1)). Pinch strength (thumb - middle finger) significantly increased (worn-not worn difference (N): mean = -4.1, CI95 (1.6, 6.6)). Analysis of factors related to improvement in hand function when wearing the SEM Glove extracted manual muscle tests (MMTs) of the upper extremity 4 or higher. The odds ratio was 6.11. CONCLUSIONS: Use of the SEM Glove improved the pinch strength of patients with functional disorders of the hands.
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Dedos/fisiopatología , Fuerza de Pellizco , Dispositivos de Autoayuda , Actividades Cotidianas , Adulto , Anciano , Diseño de Equipo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Proyectos Piloto , Valor Predictivo de las Pruebas , Adulto JovenRESUMEN
Ergometers are safe devices for patients and elderly individuals, as the exercise intensity can be controlled. Moreover, ergometer exercises, which remove the load from body weight on the leg joint, would better reflect training conditions in locations where the force of gravity is lower than that on Earth, such as the International Space Station or on the surface of Mars. The purpose of this study was not only to validate an ergometer exercise model for measuring oxygen uptake and knee joint reaction force by comparison with experimental results, but also to consider a strategy for electrically stimulating leg joint muscles to modulate them under altered gravity.
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Ejercicio Físico , Ergometría , Gravedad Alterada , Humanos , Articulación de la Rodilla , Pierna , Músculo Esquelético , OxígenoRESUMEN
Matsuse, H, Hashida, R, Takano, Y, Omoto, M, Nago, T, Bekki, M, and Shiba, N. Walking exercise simultaneously combined with neuromuscular electrical stimulation of antagonists resistance improved muscle strength, physical function, and knee pain in symptomatic knee osteoarthritis: a single-arm study. J Strength Cond Res 31(1): 171-180, 2017-A hybrid training system (HTS) was developed as a way to combine the application of electrical stimulation and voluntary contraction. Moreover, we developed a novel training method using HTS during walking (HTSW). This study was designed to evaluate the effect of HTSW on muscle strength, physical function, and knee pain in knee osteoarthritis (KOA). Eleven subjects (age: 74.0 ± 8.5 years) participated and performed HTSW for 30 minutes 3 times a week for 12 weeks. Isokinetic knee extension/knee flexion torque, muscle volume, one-leg standing test (OST), functional reach test, 10-m maximum gait speed, timed up and go test, 6-minute walking test, knee pain using Visual Analog Scale (VAS), and Japan Knee Osteoarthritis Measure (JKOM) were assessed. Knee extension torque significantly increased from 1.02 ± 0.29 N·m·kg pretraining to 1.23 ± 0.33 N·m·kg posttraining (P < 0.01, ES = 0.68). Knee flexion torque significantly increased from 0.65 ± 0.18 N·m·kg pretraining to 0.78 ± 0.17 N·m·kg posttraining (p < 0.01). Muscle volume significantly increased from 9.00 ± 2.84 mm pretraining to 10.37 ± 3.16 mm at the end of training (p ≤ 0.05). All the physical functions except OST were significantly improved. The JKOM score improved from 26.7 ± 18.30 pretraining to 17.2 ± 14.02 at the end of training (p < 0.01). The VAS score significantly decreased from 35.4 ± 22.59 pretraining to 16.5 ± 19.73 at the end of training (p ≤ 0.05). Hybrid training system during walking may be an effective training method for the treatment of people with KOA.
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Terapia por Estimulación Eléctrica/métodos , Terapia por Ejercicio/métodos , Articulación de la Rodilla/fisiopatología , Fuerza Muscular/fisiología , Osteoartritis de la Rodilla/terapia , Caminata/fisiología , Adulto , Anciano , Femenino , Humanos , Masculino , Osteoartritis de la Rodilla/fisiopatología , Dolor/fisiopatología , Dimensión del DolorRESUMEN
BACKGROUND & AIMS: Exercise is a first-line therapy for patients with non-alcoholic fatty liver disease (NAFLD). We sought to: 1) summarize effective aerobic and resistance exercise protocols for NAFLD; and 2) compare the effects and energy consumption of aerobic and resistance exercises. METHODS: A literature search was performed using PubMed, Web of Science, and Scopas to January 28, 2016. From a total of 95 articles, 23 studies including 24 aerobic and 7 resistance exercise protocols were selected for the summary of exercise protocols. Twelve articles including 13 aerobic and 4 resistance exercise protocols were selected for the comparative analysis. RESULTS: For aerobic exercise, the median effective protocol was 4.8 metabolic equivalents (METs) for 40min/session, 3times/week for 12weeks. For resistance exercise, the median effective protocol was 3.5 METs for 45min/session, 3times/week for 12weeks. Aerobic and resistance exercise improved hepatic steatosis. No significant difference was seen in the duration, frequency, or period of exercise between the two exercise groups; however, %VO2max and energy consumption were significantly lower in the resistance than in the aerobic group (50% [45-98] vs. 28% [28-28], p=0.0034; 11,064 [6394-21,087] vs. 6470 [4104-12,310] kcal/total period, p=0.0475). CONCLUSIONS: Resistance exercise improves NAFLD with less energy consumption. Thus, resistance exercise may be more feasible than aerobic exercise for NAFLD patients with poor cardiorespiratory fitness or for those who cannot tolerate or participate in aerobic exercise. These data may indicate a possible link between resistance exercise and lipid metabolism in the liver. LAY SUMMARY: Both aerobic and resistance exercise reduce hepatic steatosis in non-alcoholic fatty liver disease (NAFLD) with similar frequency, duration, and period of exercise (40-45min/session 3times/week for 12weeks); however, the two forms of exercise have different characteristics. Intensity and energy consumption were significantly lower for resistance than for aerobic exercise. Resistance exercise may be more feasible than aerobic exercise for NAFLD patients with poor cardiorespiratory fitness or for those who cannot tolerate or participate in aerobic exercise.
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Ejercicio Físico/fisiología , Enfermedad del Hígado Graso no Alcohólico/terapia , Entrenamiento de Fuerza/métodos , Humanos , Selección de PacienteRESUMEN
The hybrid training system (HTS) resists the motion of a volitionally contracting agonist muscle using force generated by its electrically stimulated antagonist. We have developed a new training method using the principle of HTS. This study was designed to evaluate the effect of HTS with electrical stimulation on muscle strength and physical function by comparing it against training without electrical stimulation in older adults. 16 subjects were randomly divided into two groups: the squat and single leg lift training (control, CTR) group, and the CTR with HTS training group. Some electrical stimulation was applied to the quadriceps and hamstring muscles in the HTS group. The subjects performed training for 25 min per session 3 times a week for 12 weeks. At points before and after the research maximal isokinetic torque, knee-flexors (KFT) and knee-extensors (KET), a one-leg standing test (OLT), a functional reach test (FRT), a 10-meter maximal gait time (10MGT) and Timed up & go test (TUG) were conducted. None of the subjects had any injuries during the study period. TUG significantly improved after the training period in both the HTS group (7.15 sec to 6.01 sec P = 0.01) and in the CTR.
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Estimulación Eléctrica , Contracción Muscular , Músculo Esquelético/fisiología , Anciano , Femenino , Humanos , Masculino , Músculo Esquelético/inervación , Proyectos PilotoRESUMEN
Performing aerobics and resistance exercise at exactly the same time has not been available although combining both types of exercise in one training program has been attempted. The hybrid training system (HTS) is a resistance exercise that combines voluntary concentric muscle contractions with electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on a cycle ergometer (HCE). Growth hormone (GH) and lactate are indicators of adequate training intensity. Interleukin-6 (IL-6) reflects enhancing lipid metabolism. The purpose of this study was to show that HCE provides sufficient exercise to stimulate the secretion of GH, lactate and IL-6. We compared an HCE test with cycle ergometer alone (CE). Ten healthy male subjects performed HCE and CE tests for 30 minutes each. The workload of both tests was set the same at 40% of each subject's peak oxygen uptake. For HCE, 2-minute HTS and 1-minute rest intervals were repeated. GH, lactate, and IL-6 were evaluated before and immediately after exercise, and at 15, 30 and 60 minutes. GH and lactate increased immediately after HCE. Moreover, the degree of the increases in GH after HCE (0 and 15 minutes) was higher than that after CE. IL-6 increased after HCE at 30 min, and the rate of change was higher than for CE. These results showed that HCE was more efficient in stimulating acute increases in GH, lactate and IL-6 than CE at the same workload. We may be able to combine electrically stimulated resistance exercise with aerobic exercise using HCE.
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Ciclismo , Ejercicio Físico , Hormona del Crecimiento/sangre , Interleucina-6/sangre , Músculos/fisiología , Estimulación Eléctrica , Electrodos , Humanos , Ácido Láctico/sangre , Masculino , Adulto JovenRESUMEN
BACKGROUND: Musculoskeletal atrophy is one of the major problems of extended periods of exposure to weightlessness such as on the International Space Station (ISS). We developed the Hybrid Training System (HTS) to maintain an astronaut's musculoskeletal system using an electrically stimulated antagonist to resist the volitional contraction of the agonist instead of gravity. The present study assessed the system's orbital operation capability and utility, as well as its preventative effect on an astronaut's musculoskeletal atrophy. METHODS: HTS was attached to the non-dominant arm of an astronaut staying on the ISS, and his dominant arm without HTS was established as the control (CTR). 10 sets of 10 reciprocal elbow curls were one training session, and 12 total sessions of training (3 times per week for 4 weeks) were performed. Pre and post flight ground based evaluations were performed by Biodex (muscle performance), MRI (muscle volume), and DXA (BMD, lean [muscle] mass, fat mass). Pre and post training inflight evaluations were performed by a hand held dynamometer (muscle force) and a measuring tape (upper arm circumference). RESULTS: The experiment was completed on schedule, and HTS functioned well without problems. Isokinetic elbow extension torque (Nm) changed -19.4% in HTS, and -21.7% in CTR. Isokinetic elbow flexion torque changed -23.7% in HTS, and there was no change in CTR. Total Work (Joule) of elbow extension changed -8.3% in HTS, and +0.3% in CTR. For elbow flexion it changed -23.3% in HTS and -32.6% in CTR. Average Power (Watts) of elbow extension changed +22.1% in HTS and -8.0% in CTR. For elbow flexion it changed -6.5% in HTS and -4.8% in CTR. Triceps muscle volume according to MRI changed +11.7% and that of biceps was +2.1% using HTS, however -0.1% and -0.4% respectively for CTR. BMD changed +4.6% in the HTS arm and -1.2% for CTR. Lean (muscle) mass of the arm changed only +10.6% in HTS. Fat mass changed -12.6% in HTS and -6.4% in CTR. CONCLUSIONS: These results showed the orbital operation capability and utility, and the preventive effect of HTS for an astronaut's musculoskeletal atrophy. The initial flight data together with the ground data obtained so far will be utilized in the future planning of human space exploration.