• PNF and Movement
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• v.18 no.3
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• pp.393-401
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• 2020

Purpose: In recent years, there has been increasing interest in using blood flow-restricted exercise (BFRE) or KAATSU training. The KAATSU training method, which partially restricts arterial inflow and fully restricts venous outflow in the working musculature during exercise at reduced exercise intensities, has been proven to result in substantial increases in both muscle hypertrophy and strength. The purpose of this study was to investigate the proper level of pressure for KAATSU training using compound muscle action potential (CMAP) analysis. Methods: Twenty-two healthy adults voluntarily participated in this study. CMAP was conducted by measuring the terminal latency and amplitude using a motor nerve conduction velocity test. For reference-line, supramaximal electrical stimulation was applied to the median nerves of the participants to obtain CMAP for the abductor pollicis brevis. For baseline, the intensity of the electrical stimulation was decreased to a level at which the CMAP amplitude was about a third of the CMAP amplitude obtained by the supramaximal electrical stimulation. The pressure levels for the KAATSU were set as a systolic blood pressure (strong pressure), the median values of systolic and diastolic blood pressure (intermediate pressure), and diastolic blood pressure (weak pressure). In the KAATSU condition, CMAP was performed under the same conditions as baseline after low-intensity thumb abduction exercises were performed at the subjects' own pace for one minute. Results: As the pressure increased, the CMAP amplitude was significantly increased, signifying that more muscle fibers were recruited. Conclusion: This study found that KAATSU training recruited more muscle fibers than low-intensity exercise without the restriction of blood flow.

• Journal of Life Science
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• v.29 no.7
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• pp.800-808
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• 2019

Charcot-Marie-Tooth disease (CMT) is a group of rare peripheral neuropathies characterized by progressive muscle weakness and atrophy and areflexia in the upper and lower extremities. The most common subtype of CMT is CMT1A, which is caused by a tandem duplication of the PMP22 gene in the 17p12 region. Patients with CMT1A show a loose genotype-phenotype correlation, which suggests the existence of secondary genetic or association factors. Recently, polymorphisms of rs71428439 (n.83A>G) and rs2292832 (n.86T>C) in the MIR149 have been reported to be associated with late onset and mild phenotypic CMT1A severity. The aim of this study was to examine the intrafamilial heterogeneities of clinical phenotypes according to the genotypes of these two SNPs in MIR149. For this study, we selected 6 large CMT1A families who showed a wide range of phenotypic variation. This study suggested that both SNPs were related to the onset age and severity in the dominant model. In particular, the AG+GG (n.83A>G) and TC+CC genotypes (n.86T>C) were associated to late onset and mild symptoms. Motor nerve conduction velocity (MNCV) was not related to the MIR149 genotypes. These results were consistent with the previous studies. Therefore, we suggest that the rs71428439 and rs2292832 variants in MIR149 may serve as genetic modifiers of CMT1A intrafamilial phenotypic heterogeneity, as they have a role in the unrelated patients. This is the first study to show an association using large families with variable clinical CMT1A phenotypes. The results will be helpful in the molecular diagnosis and treatment of patients with CMT1A.