Agonist contractions against electrically stimulated antagonists11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.

Yanagi, Tadahiro; Shiba, Naoto; Maeda, Takashi; Iwasa, Kiyohiko; Umezu, Yuichi; Tagawa, Yoshihiko; Matsuo, Shigeaki; Nagata, Kensei; Yamamoto, Takatsugu; Basford, Jeffrey R.

doi:10.1016/s0003-9993(02)04948-1

Cited by 54 publications

(15 citation statements)

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“…The system was basically the same as those used in previous ground based experiments [ 16 – 22 ], however it was designed and manufactured for use in the ISS under the criteria of NASA (Chiyoda Advance Solutions, CHIYODA CORPORATION, Yokohama, Japan). For example, the hardware of the ground model was changed so that harmful gas would not be generated in case of a fire, and the electromagnetic wave produced by the stimulator had no adverse effects on ISS.…”

Section: Methodsmentioning

confidence: 99%

“…We have developed a compact training device named “hybrid training system” (HTS) that is designed to maintain the musculoskeletal system of astronauts by using an electrically stimulated antagonist to resist the volitional contraction of agonist muscles ( Fig 1 ) [ 16 – 22 ]. HTS, which utilizes electrically stimulated antagonist force as resistance to joint motion instead of gravity, causes electrically stimulated muscles to provide resistance to the motion of an antagonist muscle undergoing training.…”

Section: Introductionmentioning

confidence: 99%

“…During HTS training, both flexion and extension muscles contract simultaneously, and longitudinal force load will be applied on the sandwiched bone by these contracting muscles. Multiple ground-based experiments [ 16 – 21 ] and a parabolic flight verification [ 22 ] have been encouraging as to the possibility of use by astronauts, but, thus far, evaluation in space has not been conducted.…”

Section: Introductionmentioning

confidence: 99%

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Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station

et al. 2015

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BackgroundMusculoskeletal 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.MethodsHTS 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).ResultsThe 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.ConclusionsThese 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.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station

et al. 2015

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“…The present study aimed to validate an ergometer exercise model over a wide range of conditions to estimate oxygen uptake and reaction forces at leg joints and vertebral bodies by comparing the outcomes with experimental results, to develop a strategy for electrically stimulating antagonist muscles of joint motion to modulate oxygen uptake and joint loading under altered gravity, and to determine optimal conditions to satisfy conflicting requirements. A hybrid training system (HTS) that combines the electrical stimulation and volitional contraction of antagonist and agonist muscles, respectively, is an effective type of training [4] even for upper limbs under microgravity [5]. Co-contractile motions in the HTS can counteract the reduced effect of the gravitational force on leg joints during ergometer exercise.…”

Section: Astesj Issn: 2415-6698mentioning

confidence: 99%

Simulation Strategy to Enhance Oxygen Uptake and Reaction Forces at Leg Joints and Vertebral Bodies During Ergometer Exercise Under Altered Gravity

Tagawa¹,

Omoto²,

Matsuse³

et al. 2018

Adv. sci. technol. eng. syst. j.

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Moderate exercise has been implemented in spaceflight programs to prevent muscle and joint damage under extreme circumstances such as microgravity. Although the physical effects of exercise have been investigated experimentally, advanced modeling and simulation techniques are powerful tools that could provide insight into the physical limitations, optimal conditions, and mechanisms that might lead to muscle and joint damage. Ergometers are safe for patients and elderly individuals because exercise intensity can be easily regulated. Moreover, ergometer exercise that removes the load imposed by body weight on leg joints would better reflect training conditions in locations such as the International Space Station or on the surfaces of the Moon and Mars, where the force of gravity is lower than that on the Earth. A hybrid training system (HTS) that combines the electrical stimulation of antagonist muscles and volitional contraction of agonist muscles is an effective training method. Co-contractile motions in the HTS can counteract the reduced effect of gravitational force on leg joints during ergometer exercise. The present study aimed to validate the ability of an ergometer exercise model to measure oxygen uptake and joint reaction forces by comparison with experimental results and create strategies for electrically stimulating leg joint muscles for modulation under altered gravity. The simulation results suggested that the HTS could easily control the magnitude of oxygen uptake and joint reaction forces. Optimal cycling conditions to achieve desirable values for oxygen uptake and joint reaction forces would help to maintain the health of astronauts and appropriate exercise programs could be implemented in constrained space facilities.

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“…Hybrid training (HYB) was developed to prevent muscle atrophy in astronauts spending long periods in space stations 7. In the present study, we used HYB as a form of exercise therapy for NAFLD.…”

Section: Introductionmentioning

confidence: 99%

Therapeutic effect of hybrid training of voluntary and electrical muscle contractions in middle-aged obese women with nonalcoholic fatty liver disease: a pilot trial

Oh¹,

Maruyama²,

Eguchi³

et al. 2015

TCRM

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BackgroundExercise training is an effective therapy for nonalcoholic fatty liver disease (NAFLD). Hybrid training (HYB) of voluntary and electrical muscle contractions was developed to prevent disuse atrophy during space flight. HYB can be applied to obtain a strength training effect accompanying articular movement. In this pilot study, we aimed to investigate the therapeutic efficacy of HYB in NAFLD.MethodsA total of 15 middle-aged obese women with NAFLD who had no improvement in serum alanine aminotransferase levels and/or liver fat deposition after 12 weeks of lifestyle counseling participated in an HYB program. HYB of the quadriceps and hamstrings was conducted for 20 minutes twice a week for 24 weeks.ResultsNAFLD patients showed attenuated intramyocellular lipid levels in the quadriceps after the HYB intervention (−15.5%). Levels of leptin (−17.4%), tumor necrosis factor-α (−23.2%), and interleukin-6 (−30.5%) were also decreased after the intervention. HYB led to a significant body weight reduction (−4.7%), which in turn was associated with a significant decrease in serum alanine aminotransferase (−35.8%), gamma-glutamyl transpeptidase (−21.6%), ferritin (−16.0%), oxidative stress (−17.8%) levels, and insulin resistance values (−2.7%).ConclusionIn NAFLD, HYB exerts an antiobesity effect and attenuates liver dysfunction and insulin resistance in association with an increase in muscle strength and a decrease in ectopic muscle fat. Therefore, HYB has great potential as a new type of exercise therapy for liver disease in patients with NAFLD.

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Agonist contractions against electrically stimulated antagonists11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.

Cited by 54 publications

References 10 publications

Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station

Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station

Simulation Strategy to Enhance Oxygen Uptake and Reaction Forces at Leg Joints and Vertebral Bodies During Ergometer Exercise Under Altered Gravity

Therapeutic effect of hybrid training of voluntary and electrical muscle contractions in middle-aged obese women with nonalcoholic fatty liver disease: a pilot trial

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