• Journal of the Korean Society of Physical Medicine
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• v.19 no.2
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• pp.29-45
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• 2024

PURPOSE: This study aimed to compare the effects of pain level, lower back pain dysfunction level, psychosocial level, hip abductor strength (HAS), number of positive lumbar instability tests, and dynamic balance (DB) by applying lumbar stabilization exercises according to the presence or absence of gluteus medius muscle weakness in chronic lower back pain (CLBP) patients with lumbar instability. METHODS: Thirty-five CLBP patients with lumbar instability were divided into the gluteus medius weakness (n = 18) and gluteus medius non-weakened (n = 17) groups using the gluteus medius manual muscle test. Intervention applied conservative physical therapy and lumbar stabilization exercises to both groups that lasted three times a week for four weeks. To compare the intervention effects, the quadruple visual analog scale (QVAS), the Korean version of the Oswestry disability index (K-ODI), fear-avoidance beliefs questionnaire (FABQ), HAS, lumbar instability tests positive response counter (LIC), and DB were measured. RESULTS: Significant differences were shown for QVAS, K-ODI, FABQ, HAS, LIC, and DB for both groups pre- and post-intervention (p < .05). Compared to the gluteus medius weakness group, the gluteus medius non-weakened group showed a significant difference (p < .05) in the changes in QVAS, K-ODI, FABQ-W, FABQ-total, and HAS. CONCLUSION: In CLBP patients with lumbar instability, having gluteus medius weakness was less effective in improving lumbar stabilization exercise than gluteus medius non-weakness regarding pain level, lower back pain dysfunction level, psychosocial level excluding physical activity, and hip abductor strength. Therefore, additional gluteus medius strengthening exercises are necessary for patients with lumbar instability and gluteus medius muscle weakness.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.1
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• pp.71-82
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• 2015

PURPOSE: The aim of this study is to compare changes in the thickness of the gluteus medius muscle fiber between chronic low back pain(clbp) with gluteus medius weakness and healthy subject. METHODS: Ultrasound imaging was used to measure in the thickness of each fiber of the gluteus medius muscle based on maximal muscle contraction during abduction motion of the hip joint in a healthy group (11 subjects) and a chronic CLBP group (21 subjects). An independent t-test was performed to analyze the difference of thickness in each fiber of the gluteus medius muscle and the rate of changes in the fibers in the two groups. RESULTS: The fiber thickness changes in the gluteus medius muscle were significantly lower for the posterior fiber in the CLBP group compared to the healthy group (p<0.01). The changes in rate of difference of thickness the posterior part of the gluteus medius muscle was significantly lower in the CLBP group than in the healthy group (p<0.05). CONCLUSION: The findings of this study CLBP patients with weakness of the gluteus medius muscle that lower for the posterior fiber's difference of thickness and rate of change in the CLBP group compared to the healthy group. Indicate that rehabilitation of CLBP patients with weakness of the gluteus medius muscle should consider the functions of posterior fiber of the gluteus medius muscle.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.2
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• pp.53-57
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• 2017

PURPOSE: The purpose of study was to clear up the environmental risk factor that can be easily occurred unstability of hip during gait and one leg standing at various ramp angle. METHODS: Twenties healthy males of 69 subjects is participated in this study. Participants was measured activation on gluteus medius muscle during both conditions (walk across the ramp and one leg stand in the transverse direction) of seven different angle. The measured data were analyzed using one-way ANOVA to investigate the effect of muscle activation on the each condition. The statistical analyses were performed using SPSS ver. 18.0 and p-value less than .05 were considered significant for all cases. A post-hoc test was performed by Bonferoni method. RESULTS: The study showed that more muscle activities on gluteus medius is increased by increasing the ramp angle. Post-hoc analysis demonstrated that the peak and mean of muscle activity increased significantly with a ramp angle of $15^{\circ}$ and $25^{\circ}$ during gait and one-leg stand. CONCLUSION: According to the study results, impaired balance can be easily occurred when cross walk and one-leg stand on a ramp from higher than $15^{\circ}$, and highest risk was angle of $25^{\circ}$ or more. As a people with gluteus medius muscle weakness walks a ramp, the ramp angle has a cross relationship with the impaired balance. If people with gluteus medius weakness walk on the more than $10^{\circ}$ of ramp angle, they will need a lot of attention for prevent impaired balance.

• Physical Therapy Rehabilitation Science
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• v.10 no.4
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• pp.487-492
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• 2021

Objective: This study aimed to identify the effects of assuming two types of posture (standing and kneeling) during squat exercise on lower body muscle activity. Design: Cross-sectional study Methods: Twenty-five healthy adults (18 men and 7 women) were instructed to perform the squat exercises while assuming two types of posture (standing and kneeling). EMG (Electromyography) data (% maximum voluntary isometric contraction) were recorded three times from the rectus femoris (RF), gluteus maximus (GMax), gluteus medius (GMed) and biceps femoris (BF) of participant's dominant side and the mean values were analyzed. Results: During the squat exercise with all postures, there was statistically significant difference on rectus femoris, gluteus maximus, gluteus medius, and biceps femoris muscle activity (p<0.05). The results showed that, there was significantly greater rectus femoris, gluteus medius, and biceps femoris muscle activity in standing posture than in kneeling position (p<0.05). However, the gluteus maximus muscle activity was significantly greater with kneeling posture compared to standing posture (p<0.05). Conclusions: With standing posture, it is showed that rectus femoris, gluteus medius, and biceps femoris muscle activity was greater than kneeling position. While the gluteus maximus muscle activity with standing posture was less than with kneeling posture. Therefore, it is considered that this study can be used as a selective indicator of exercise posture for strengthening specific muscle or weakness caused by paralysis.

• Physical Therapy Korea
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• v.28 no.1
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• pp.27-35
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• 2021

A weak or dysfunctional gluteus medius (Gmed) is related to several pathologies, and individuals with hip abductor weakness have Gmed weakness. This study aimed to systematically review the literature associated with the anatomy and function of the Gmed, and the prevalence, pathology, and exercise of Gmed weakness. Papers published between 2010 and 2020 were retrieved from MEDLINE, Google Academic Search, and Research Information Sharing Service. The database search used the following terms: (glut* OR medius OR hip abduct*) AND weak*. The Gmed plays an important role in several functional activities as a primary hip abductor by providing pelvic stabilization and controlling hip adduction and internal rotation. Weakness of the Gmed is associated with many disorders including balance deficit, gait and running disorders, femoroacetabular impingement, snapping hip, gluteal tendinopathy, patellofemoral pain syndrome, osteoarthritis, iliotibial band syndrome, anterior cruciate ligament injury, ankle joint injuries, low back pain, stroke, and nocturia. Overuse of the tensor fasciae latae (TFL) as a hip abductor due to Gmed weakness can also cause several pathologies such as pain in the lower back and hip and degenerative hip joint pathology, which are associated with dominant TFL. Similarly, lateral instability and impaired movements such as lumbar spine lateral flexion or lateral tilt of the pelvis can occur due to compensatory activation of the quadratus lumborum for a weakened Gmed while exercising. Therefore, the related activation of synergistic muscles or compensatory movement should be considered when prescribing Gmed strengthening exercises.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.2
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• pp.9-19
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• 2019

PURPOSE: This study compared the effects of three different clamshell exercises (CLAM) on the gluteus medius (GMED), quadratus lumborum (QL), anterior hip flexor (AHF), gluteus medius/quadratus lumborum ratio, and gluteus medius/anterior hip flexor ratio by studying the activities of participants with GMED weakness. METHODS: Eleven subjects with weak GMED participated in this study. Subjects performed CLAM under three different conditions (standard, and modified 1 and 2). Surface electromyography was then used to measure the muscle activity and one-way repeated-measures analysis of variance was used to assess the statistical significance of the measured variables. RESULTS: GMED and the QL muscle activities did not differ significantly between the standard CLAM and the modified CLAM with the 2 different foot positions (F=4.74, P=.02; F=4.57, P=.02, respectively). AHF activity was significantly different in the two different foot positions when compared to the standard CLAM (F=11.17, P=.00). However, there was no significant difference between the AHF activities for the two different foot positions (P=.09). Finally, GMED/QL and GMED/AHF ratios were not significantly different between the three different CLAM exercises (F=.63, P=.55; F=.82, P=.45, respectively). CONCLUSION: Modified CLAM can be recommended as a good method to minimize AHF activity while maintaining GMED activity in subjects with weak GMED.

• Physical Therapy Korea
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• v.23 no.3
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• pp.57-67
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• 2016

Background: Many previous studies recommended the side-lying hip abduction (SHA) exercise for targeting the gluteus medius (Gmed) and gluteus maximus (Gmax) muscle activity while the decreasing tensor fasciae latae (TFL) activation. Mischoice of hip position and angle in SHA may increase the risk of lower extremity injuries and undesirable muscle activation. However, information is limited on the effect of composite hip flexion angles and hip rotation on the gluteal muscle activity during SHA. Objects: This study aimed to compare muscle activity (Gmed, TFL, and Gmax) and activity ratios (Gmed/TFL, Gmax/TFL, and Gmed/Gmax) using surface electromyography (EMG) during SHA exercise at three different hip flexion angles either with or without internal rotation (IR) in subjects with Gmed weakness. We hypothesized that applying hip flexion and IR during SHA would increase gluteal muscle activity and decrease TFL activity. Methods: Muscle activity and activity ratios in 20 volunteers with Gmed weakness during 6 different SHA were investigated with surface EMG. One-way repeated-measures analysis of variance was used to determine the statistical significance. Results: Significant differences were found among the six different exercises for Gmed ($F_{2,41}=11.817$, p<.001) and Gmax ($F_{3,52}=5.513$, p=.003) muscle activity, and Gmed/TFL ($F_{3,54}=8.735$, p<.001) and Gmax/TFL ($F_{2,37}=4.019$, p=.028) activity ratios. Conclusion: Applying hip flexion is an effective method for increasing gluteal activity, and it elicits great Gmed/TFL and Gmax/TFL activity ratios during SHA in subjects with Gmed weakness.

• Physical Therapy Korea
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• v.30 no.1
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• pp.68-77
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• 2023

Background: The weakness of the gluteus medius (GM) is associated with various musculoskeletal disorders. The increasing GM activity without synergistic dominance should be considered when prescribing pelvic drop exercise (PD). Isometric hip extension or flexion of the non-weight bearing leg using thera-band at the ankle during PD may influence hip abductor activities. Objects: To determine how isometric hip extension or flexion of the non-weight bearing leg using thera-band at the ankle during PD influences the activities of three subdivisions of GM (anterior, GMa; middle, GMm; posterior, GMp), tensor fasciae latae (TFL), contralateral quadratus lumborum (QL), and GMp/TFL, GMm/QL activity ratios in patients with GM weakness. Methods: Twenty-three patients with GM weakness were recruited. Three types of PD were performed: PD, PD with an isometric hip extension of the non-weight bearing leg (PDE), and PD with an isometric hip flexion of the non-weight bearing leg (PDF). Surface electromyography (SEMG) was used to measure hip abductor activities. One-way repeated-measures analysis of variance was used to assess the statistical significance of muscle activities and muscle activity ratios. Results: GMa, GMm, and GMp activities were significantly greater during PDF than during PD and PDE (p < 0.001, p = 0.001; p = 0.001, p = 0.005; p = 0.004, p = 0.004; respectively). TFL activity was significantly greater during PDE than during PD and PDF (p < 0.001, p < 0.001, respectively). QL activity was significantly greater during PDF than during PD (p = 0.003). GMp/TFL activity ratio was significantly lower during PDE than during PD and PDF (p = 0.001, p = 0.001, respectively). There were no significant differences in the GMm/QL activity ratio. Conclusion: PDF may be an effective exercise to increase the activities of all three GM subdivisions while minimizing the TFL activity in patients with GM weakness.