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

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259856
Author(s):  
Hiroshi Tajima ◽  
Hiroo Matsuse ◽  
Ryuki Hashida ◽  
Takeshi Nago ◽  
Masafumi Bekki ◽  
...  

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.

Author(s):  
Toshiki Kutsuna ◽  
Hitoshi Sugawara ◽  
Hideaki Kurita ◽  
Satomi Kusaka ◽  
Tetsuya Takahashi

Background: Low-intensity resistance training (RT) combined with neuromuscular electrical stimulation (NMES) is one method of exercise to improve the deterioration of physical function. However, it is unclear whether low-intensity RT combined with NMES (RT + NMES) can be safely implemented. Objective: This study aimed to examine the influence of low-intensity RT + NMES on autonomic activity and cardiovascular responses in healthy adults. Methods: This study was an open-label, randomized controlled cross-over trial. The exercise intensity of isometric knee extension RT was set to 40% of the maximum voluntary contraction (peak torque). NMES was adjusted to a biphasic asymmetrical waveform with the frequency maintained at 50 Hz and a phase duration of 300 [Formula: see text]s. The difference in the change in autonomic activity and cardiovascular responses was compared by assessing heart rate variability, blood pressure, and heart rate during RT and [Formula: see text]. Results: Twenty healthy male college students (mean age [Formula: see text] years) participated in this study. The ratio of low- and high-frequency components of heart rate variability, systolic blood pressure, and heart rate increased during exercise in the RT and [Formula: see text] sessions ([Formula: see text]). There were no significant differences in autonomic activity and cardiovascular responses throughout the sessions during RT and [Formula: see text]. Conclusion: In conclusion, our results demonstrated that low-intensity [Formula: see text] was safe and did not induce excessive autonomic and cardiovascular responses in healthy adults.


Author(s):  
Lucas Capalonga ◽  
Cintia Laura Pereira Araújo ◽  
Vítor Scotta Hentschke ◽  
Douglas Dalcin Rossato ◽  
Edson Quagliotto ◽  
...  

The aim was to analyze the effect of neuromuscular electrical stimulation (NMES) and photobiomodulation (PBMT) on cardiovascular parameters, hemodynamic function, arterial baroreflex sensitivity (BRS), and autonomic balance (ANS) of rats with heart failure (HF). Male Wistar rats (220-290g) were organized into five groups: Sham (n=6), Control-HF (n=5), NMES-HF (n=6), PBMT-HF (n=6), and NMES+PBMT-HF (n=6). Myocardial infarction (MI) was induced by left coronary artery ligation. Animals were subjected to an eight-week NMES and PBMT protocol. Statistical analysis with the General Linear Model (GLM) followed by the Bonferroni post hoc test. Rats of NMES-HF group showed a higher MI area than Control-HF group (P=0.003), PBMT-HF (P=0.002), and NMES+PBMT-HF (P=0.012). NMES-HF and NMES+PBMT-HF showed higher pulmonary congestion (P=0.004 and P=0.02), and lower systolic pressure (P=0.019 and P=0.002) than Sham group. NMES+PBMT-HF showed lower mean arterial pressure (P=0.02) than Sham group. Control-HF showed a higher heart rate than NMES-HF and NMES+PBMT-HF (P=0.017 and P=0.013). There was no difference in the BRS and ANS variables between groups. In conclusion, eight-week NMES isolated or associated with PBMT protocol reduced basal heart rate, systolic and mean arterial pressure, without influence on baroreflex sensibility and autonomic control, and no effect of PBMT was seen in rats with HF.


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