Electrical muscle stimulation improves vastus medialis quality: A single-case experimental design

Summary: Background & Aims: Studies have shown that qualitative changes, such as ectopic fat accumulation, are associated with muscle weakness and degeneration of the articular cartilage. This study aimed to investigate the effects and timing of electrical muscle stimulation on the vastus m...

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Main Authors: Yoshitsugu Tanino, Yuki Fukumoto, Wataru Yamazaki, Takaki Yoshida
Format: Article
Language:English
Published: Elsevier 2025-10-01
Series:Clinical Nutrition Open Science
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Online Access:http://www.sciencedirect.com/science/article/pii/S2667268525000853
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author Yoshitsugu Tanino
Yuki Fukumoto
Wataru Yamazaki
Takaki Yoshida
author_facet Yoshitsugu Tanino
Yuki Fukumoto
Wataru Yamazaki
Takaki Yoshida
author_sort Yoshitsugu Tanino
collection DOAJ
description Summary: Background & Aims: Studies have shown that qualitative changes, such as ectopic fat accumulation, are associated with muscle weakness and degeneration of the articular cartilage. This study aimed to investigate the effects and timing of electrical muscle stimulation on the vastus medialis using a single-case experimental design to evaluate improvement in muscle quality. Methods: Three healthy males participated in this study. An “ABAB design” was employed over a 14-week period, alternating between baseline phases without electrical muscle stimulation (3 weeks each) and intervention phases with electrical stimulation (4 weeks each). Electrical muscle stimulation was applied to the vastus medialis for 30 min three times per week during the intervention phases. The intensity was adjusted to a tolerable level of discomfort. Sonographic echo intensity of the vastus medialis, reflecting intramuscular fat content, and body fat percentage were measured. Results: During the first electrical muscle stimulation phase, the effect size based on the percentage of non-overlapping data in echo intensity was 0% for all three subjects compared to the baseline. However, during the second baseline phase, subjects A and C achieved 100% (indicating very effective changes). In the second electrical muscle stimulation phase, all subjects exhibited 100%. No significant changes in body fat percentage were observed during the study. Conclusions: These findings suggest that electrical muscle stimulation must be sustained for at least 4 weeks to effectively reduce intramuscular fat and improve vastus medialis muscle quality.
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publishDate 2025-10-01
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series Clinical Nutrition Open Science
spelling doaj-art-5a2c3064e7d84d3ea9b3992d60a38e292025-08-20T04:01:57ZengElsevierClinical Nutrition Open Science2667-26852025-10-016317419110.1016/j.nutos.2025.07.013Electrical muscle stimulation improves vastus medialis quality: A single-case experimental designYoshitsugu Tanino0Yuki Fukumoto1Wataru Yamazaki2Takaki Yoshida3Corresponding author. Department of Physical Therapy, Kansai University of Health Sciences, 2-11-1 Wakaba Kumatori, Sennan Osaka, 590-0482, Japan.; Department of Physical Therapy, Kansai University of Health Sciences, Wakaba Kumatori, Sennan Osaka, JapanDepartment of Physical Therapy, Kansai University of Health Sciences, Wakaba Kumatori, Sennan Osaka, JapanDepartment of Physical Therapy, Kansai University of Health Sciences, Wakaba Kumatori, Sennan Osaka, JapanDepartment of Physical Therapy, Kansai University of Health Sciences, Wakaba Kumatori, Sennan Osaka, JapanSummary: Background & Aims: Studies have shown that qualitative changes, such as ectopic fat accumulation, are associated with muscle weakness and degeneration of the articular cartilage. This study aimed to investigate the effects and timing of electrical muscle stimulation on the vastus medialis using a single-case experimental design to evaluate improvement in muscle quality. Methods: Three healthy males participated in this study. An “ABAB design” was employed over a 14-week period, alternating between baseline phases without electrical muscle stimulation (3 weeks each) and intervention phases with electrical stimulation (4 weeks each). Electrical muscle stimulation was applied to the vastus medialis for 30 min three times per week during the intervention phases. The intensity was adjusted to a tolerable level of discomfort. Sonographic echo intensity of the vastus medialis, reflecting intramuscular fat content, and body fat percentage were measured. Results: During the first electrical muscle stimulation phase, the effect size based on the percentage of non-overlapping data in echo intensity was 0% for all three subjects compared to the baseline. However, during the second baseline phase, subjects A and C achieved 100% (indicating very effective changes). In the second electrical muscle stimulation phase, all subjects exhibited 100%. No significant changes in body fat percentage were observed during the study. Conclusions: These findings suggest that electrical muscle stimulation must be sustained for at least 4 weeks to effectively reduce intramuscular fat and improve vastus medialis muscle quality.http://www.sciencedirect.com/science/article/pii/S2667268525000853Echo intensityIntramuscular fat contentBody compositionResearch design
spellingShingle Yoshitsugu Tanino
Yuki Fukumoto
Wataru Yamazaki
Takaki Yoshida
Electrical muscle stimulation improves vastus medialis quality: A single-case experimental design
Clinical Nutrition Open Science
Echo intensity
Intramuscular fat content
Body composition
Research design
title Electrical muscle stimulation improves vastus medialis quality: A single-case experimental design
title_full Electrical muscle stimulation improves vastus medialis quality: A single-case experimental design
title_fullStr Electrical muscle stimulation improves vastus medialis quality: A single-case experimental design
title_full_unstemmed Electrical muscle stimulation improves vastus medialis quality: A single-case experimental design
title_short Electrical muscle stimulation improves vastus medialis quality: A single-case experimental design
title_sort electrical muscle stimulation improves vastus medialis quality a single case experimental design
topic Echo intensity
Intramuscular fat content
Body composition
Research design
url http://www.sciencedirect.com/science/article/pii/S2667268525000853
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AT yukifukumoto electricalmusclestimulationimprovesvastusmedialisqualityasinglecaseexperimentaldesign
AT wataruyamazaki electricalmusclestimulationimprovesvastusmedialisqualityasinglecaseexperimentaldesign
AT takakiyoshida electricalmusclestimulationimprovesvastusmedialisqualityasinglecaseexperimentaldesign