Electrically stimulated eccentric contraction during non-weight bearing knee bending exercise in the supine position increases oxygen uptake: A randomized, controlled, exploratory crossover trial

• Published in: PloS one Vol. 16; no. 11; p. e0259856
• Main Authors: Tajima, Hiroshi, Matsuse, Hiroo, Hashida, Ryuki, Nago, Takeshi, Bekki, Masafumi, Iwanaga, Sohei, Higashi, Eriko, Shiba, Naoto
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 18.11.2021; Public Library of Science (PLoS)
• Subjects: Adult; Aerobics; Astronauts; Atrophy; Atrophy, Muscular; Bed load; Bed rest; Bending; Biology and Life Sciences; Bone loss; Bone resorption; Carbon dioxide; Care and treatment; Contraction; Cross-Over Studies; Deconditioning; Diagnosis; Electric Stimulation Therapy; Electrical stimuli; Exercise; Exercise intensity; Exercise Therapy - methods; Female; Health aspects; Heart Rate; Humans; Hybrid systems; Immobilization; Insulin; Insulin resistance; Intervention; Knee; Knee - physiology; Knee Joint; Load distribution; Magnetic brain stimulation; Male; Medical laboratories; Medicine and Health Sciences; Metabolism; Methods; Motion sensors; Muscle strength; Muscles; Neuromuscular electrical stimulation; Oxygen; Oxygen - metabolism; Oxygen consumption; Oxygen uptake; Physical fitness; Physical Sciences; Physical training; Physiological aspects; Prevention; Prophylaxis; Range of motion; Rehabilitation; Risk factors; Sports training; Stimulation; Strength training; Supine Position; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0259856

It is well known that prolonged bed rest induces muscle weakness, muscle atrophy, cardiovascular deconditioning, bone loss, a loss of functional capacity, and the development of insulin resistance. Neuromuscular electrical stimulation is anticipated to be an interventional strategy for disuse due to bed rest. A hybrid training system (HTS), synchronized neuromuscular electrical stimulation for voluntary exercise using an articular motion sensor, may increase the exercise load though bed rest. We assessed oxygen uptake or heart rate during knee bending exercise in the supine position on a bed both simultaneously combined with HTS and without HTS to evaluate exercise intensity on different days in ten healthy subjects (8 men and 2 women) by a randomized controlled crossover trial. The values of relative oxygen uptake during knee bending exercise with HTS were significantly greater than those during knee bending exercise without HTS (7.29 ± 0.91 ml/kg/min vs. 8.29 ± 1.06 ml/kg/min; p = 0.0115). That increment with HTS was a mean of 14.42 ± 13.99%. Metabolic equivalents during knee bending exercise with HTS and without HTS were 2.08 ± 0.26 and 2.39 ± 0.30, respectively. The values of heart rate during knee bending exercise with HTS were significantly greater than those during knee bending exercise without HTS (80.82 ± 9.19 bpm vs. 86.36 ± 5.50 bpm; p = 0.0153). HTS could increase exercise load during knee bending exercise which is easy to implement on a bed. HTS might be a useful technique as a countermeasure against the disuse due to bed rest, for example during acute care or the quarantine for infection prophylaxis.