muscle contraction
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2022 ◽  
Vol 11 (1) ◽  
pp. 51-56
Yoshitaka Mita ◽  
Miyuki Ito ◽  
Mio Yamada ◽  
Nobuharu L. Fujii ◽  
Yasuko Manabe ◽  

J. Flodin ◽  
R. Juthberg ◽  
P. W. Ackermann

Abstract Background Neuromuscular electrical stimulation (NMES) may prevent muscle atrophy, accelerate rehabilitation and enhance blood circulation. Yet, one major drawback is that patient compliance is impeded by the discomfort experienced. It is well-known that the size and placement of electrodes affect the comfort and effect during high-intensity NMES. However, during low-intensity NMES the effects of electrode size/placement are mostly unknown. Therefore, the purpose of this study was to investigate how electrode size and pragmatic placement affect comfort and effect of low-intensity NMES in the thigh and gluteal muscles. Methods On 15 healthy participants, NMES-intensity (mA) was increased until visible muscle contraction, applied with three electrode sizes (2 × 2 cm, 5 × 5 cm, 5 × 9 cm), in three different configurations on quadriceps and hamstrings (short-transverse (ST), long-transverse (LT), longitudinal (L)) and two configurations on gluteus maximus (short-longitudinal (SL) and long-longitudinal (LL)). Current–density (mA/cm2) required for contraction was calculated for each electrode size. Comfort was assessed with a numerical rating scale (NRS, 0–10). Significance was set to p < 0.05 and values were expressed as median (inter-quartile range). Results On quadriceps the LT-placement exhibited significantly better comfort and lower current intensity than the ST- and L-placements. On hamstrings the L-placement resulted in the best comfort together with the lowest intensity. On gluteus maximus the LL-placement demonstrated better comfort and required less intensity than SL-placement. On all muscles, the 5 × 5 cm and 5 × 9 cm electrodes were significantly more comfortable and required less current–density for contraction than the 2 × 2 cm electrode. Conclusion During low-intensity NMES-treatment, an optimized electrode size and practical placement on each individual muscle of quadriceps, hamstrings and gluteals is crucial for comfort and intensity needed for muscle contraction.

2022 ◽  
Vol 12 ◽  
Hanxue Sun ◽  
Xizhong Du ◽  
Tao Zeng ◽  
Shenggang Ruan ◽  
Guoqin Li ◽  

This experiment was conducted to investigate the effects of compound probiotics on intestinal microflora and metabolome of Shaoxing ducks. A total of 640 1-day-old Shaoxing ducks were randomly divided into two treatments with eight replicates and forty ducks for each replicate. The ducks were fed basal diet (Ctrl) and basal diet supplemented with 0.15% compound probiotics (MixP). The experiment lasted for 85 days. The results showed that the abundance of Bacteroidetes and Bacteroides in MixP was higher than that in Ctrl (P &lt; 0.05). However, the abundance of Firmicutes and Oscillospira and Desulfovibrio in MixP was lower than that in Ctrl (P &lt; 0.05). Concentrations of 71 metabolites differed significantly (P &lt; 0.05) between the MixP and the Ctrl groups; for example, Pyridoxal (Vitamin B6), L-Arginine, and Betaine aldehyde were up-regulated (P &lt; 0.05), and 7-oxocholesterol, 3-hydroxy-L-kynureni-ne, and N-acetyl-d-glucosamine were down-regulated (P &lt; 0.05). KEGG was enriched in 15 metabolic pathways. The pathways of Vitamin B6 metabolism, Vascular smooth muscle contraction, Vitamin digestion and absorption, and Protein digestion and absorption were influenced by compound probiotics supplementation. Thus, supplementation of compound probiotics improved cecal heath through shifts in the cecal microbiome and metabolome.

2022 ◽  
Vol 23 (1) ◽  
Brian A. Karamian ◽  
Nicholas Siegel ◽  
Blake Nourie ◽  
Mijail D. Serruya ◽  
Robert F. Heary ◽  

AbstractElectrical stimulation is used to elicit muscle contraction and can be utilized for neurorehabilitation following spinal cord injury when paired with voluntary motor training. This technology is now an important therapeutic intervention that results in improvement in motor function in patients with spinal cord injuries. The purpose of this review is to summarize the various forms of electrical stimulation technology that exist and their applications. Furthermore, this paper addresses the potential future of the technology.

2022 ◽  
Hiroki Ohara ◽  
Shoichi Hasegawa

Abstract Conventional EMS technology cannot stimulate deep muscles to induce muscle contraction using surface electrodes. Several treatments use electrical stimulation for various neurological conditions, including stroke and spinal cord injury. One such treatment is functional electrical stimulation (FES), a form of rehabilitation in which electrical muscle stimulation (EMS) is provided while the muscles are being moved. Here, we show whether two interfering electrical stimulation pulses could stimulate the deep muscles of the forearm to control muscle contraction. The results showed that the strongest torques were generated across the subjects when the reference frequency was mid-frequency (4,000 Hz) and the beat frequencies were low (20 Hz, 40 Hz, 80 Hz, 160 Hz and 320 Hz). This study is the first counterexample to demonstrate that it is possible to control muscle contraction in the deep muscles of the forearm using surface electrodes, which was previously thought to be impossible.

2022 ◽  
Vol 17 (1) ◽  
pp. 228
Bao-Guo Jiang ◽  
Ting-Min Xu ◽  
Bo Chen ◽  
Zong-Xue Jin ◽  
Xiao-Feng Yin ◽  

2022 ◽  
Michelle J Galvan ◽  
Michael J Sanchez ◽  
Andrew J McAinch ◽  
Jeffrey D Covington ◽  
Jason B Boyle ◽  

Introduction/Purpose: Most U.S. adults (54%) do not meet minimum exercise recommendations by American College of Sports Medicine (ACSM). Neuromuscular electrical stimulation (NMES) is a novel alternate strategy to induce muscle contraction. However, effectiveness of NMES to improve insulin sensitivity and energy expenditure is unclear. The purpose of this study was to investigate the effects of four weeks of NMES on glucose tolerance in a sedentary overweight or obese population. Methods: Participants (n=10; age: 36.8 ± 3.8 years; BMI=32 ± 1.3 kg/ m2) were randomized into either control or NMES group. All participants received bilateral quadriceps stimulation (12 sessions; 30 minutes/session; 3 times/week at 50 Hz and 300 µs pulse width) altering pulse amplitude to either provide low intensity sensory level (control; tingling sensation) or at high intensity neuromuscular level (NMES; maximum tolerable levels with visible muscle contraction). Glucose tolerance was assessed by three-hour oral glucose tolerance test (OGTT), substrate utilization was measured by indirect calorimetry and body composition via dual X-ray absorptiometry at baseline and after four weeks of NMES intervention. Results: Control and NMES groups had comparable fasting blood glucose, glucose tolerance, substrate utilization, and muscle mass at baseline. Four weeks of NMES resulted in a significant improvement in glucose tolerance measured by OGTT, whereas no change was observed in control group. There was no change in substrate utilization and in muscle mass in both control and NMES groups. Conclusion: NMES is a novel and effective strategy to improve glucose tolerance in an at-risk overweight or obese sedentary population.

Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 78
Juhyun Park ◽  
Soo Woong Kim ◽  
Min Chul Cho

The LIM kinases (LIMK1 and LIMK2), known as downstream effectors, and the Rho-associated protein kinase (ROCK), a regulator of actin dynamics, have effects on a diverse set of cellular functions. The LIM kinases are involved in the function of the male urogenital system by smooth muscle contraction via phosphorylation of cofilin and subsequent actin cytoskeleton reorganization. Although LIMK1 and LIMK2 share sequence similarities as serine protein kinases, different tissue distribution patterns and distinct localization during cell cycle progression suggest other biological functions for each kinase. During meiosis and mitosis, the LIMK1/2–cofilin signaling facilitates the orchestrated chromatin remodeling between gametogenesis and the actin cytoskeleton. A splicing variant of the LIMK2 transcript was expressed only in the testis. Moreover, positive signals with LIMK2-specific antibodies were detected mainly in the nucleus of the differentiated stages of germ cells, such as spermatocytes and early round spermatids. LIMK2 plays a vital role in proper spermatogenesis, such as meiotic processes of spermatogenesis after puberty. On the other hand, the literature evidence revealed that a reduction in LIMK1 expression enhanced the inhibitory effects of a ROCK inhibitor on the smooth muscle contraction of the human prostate. LIMK1 may have a role in urethral obstruction and bladder outlet obstruction in men with benign prostatic hyperplasia. Moreover, LIMK1 expression was reduced in urethral stricture. The reduced LIMK1 expression caused the impaired proliferation and migration of urethral fibroblasts. In addition, the activated LIMK2–cofilin pathway contributes to cavernosal fibrosis after cavernosal nerve injury. Recent evidence demonstrated that short-term inhibition of LIMK2 from the immediate post-injury period prevented cavernosal fibrosis and improved erectile function in a rat model of cavernosal nerve injury. Furthermore, chronic inhibition of the LIMK2–cofilin pathway significantly restrained the cavernosal veno-occlusive dysfunction, the primary pathophysiologic mechanism of post-prostatectomy erectile dysfunction through suppressing fibrosis in the corpus cavernosum. In conclusion, the LIM kinases–cofilin pathway appears to play a role in the function of the male urogenital system through actin cytoskeleton reorganization and contributes to the pathogenesis of several urogenital diseases. Therefore, LIM kinases may be a potential treatment target in urogenital disorder.

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