• 대한물리의학회지
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• 제12권1호
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• pp.1-8
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• 2017

PURPOSE: This study was to determine the changes of abdominal muscles activation according to the heel contact methods of stair ascent in healthy young adults. METHODS: 33 healthy young subjects (mean age: $26.37{\pm}9.72$ years, age range: 20-32 years) volunteered under two conditions. They were performed stair ascent with heel contact and without heel contact. The effects of heel contact methods were assessed using the surface electromyography (sEMG) analysis during stair ascent for activation of abdominal muscles (internal oblique; IO, transverse abdominis; TrA, external oblique; EO rectus abdominis; RA). The interventions were conducted over three trials in each method, and measurements were performed on each subject by one examiner in three trials. RESULTS: Our results revealed that there were significantly greater increase in the EMG activation of IO and TrA muscles in the performance of stair ascent with heel contact (p<.05) compared to those of stair ascent without heel contact. The results also showed that there were greater decrease in the ratio of abdominal muscle activation in those of stair ascent with heel contact compared with stair ascent without heel contact. CONCLUSION: These findings demonstrated that the method of stair ascent with heel contact would suggest positive evidence for improving activation of abdominal muscles.

• Physical Therapy Rehabilitation Science
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• 제5권3호
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• pp.120-124
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• 2016

Objective: Chronic lateral epicondylitis is a condition which becomes sore and tender on the lateral side of the elbow joint damaged from overuse and repetitive use of the extensor muscles of the forearm. The purpose of this study was to investigate the effects of flexion degrees in the elbow joint on extensor carpi radialis longus and brevis and biceps brachii muscles in individuals with healthy young adults. The main purpose of this study was to suggest the feasibility of optimal elbow angle during therapeutic eccentric exercise with resistance for strengthening of wrist extensors. Design: Cross-sectional study. Methods: Thirty health young adults (male 15, female 15) participated in this study. This study measured muscle activation in four different conditions of elbow flexion, $0^{\circ}$, $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$ during eccentric exercise with weight loading in wrist extensors, extensor carpi radialis longus and brevis and biceps brachii muscles using surface electromyography. Results: The muscle activation of extensor carpi radialis showed a negative relationship with the degrees of elbow joint flexion. With increasing elbow flexion angles, the ECRL muscle activation amount was significantly lower (p<0.05). In contrast, the muscle activation of the ECRB muscle activation amount was significanlty higher (p<0.05). Conclusions: This study suggests that the eccentric exercise of wrist extension with selected activation of wrist extensor muscles according to elbow flexion positions, and suggests that the extensor carpi radialis longus and brevis will need to be strengthened for preventing and treating chronic lateral epicondylitis regardless of degrees of elbow joint flexion.

• 대한통합의학회지
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• 제4권4호
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• pp.67-75
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• 2016

Purpose: The purpose of this study was to compare Hip-Knee-Ankle(HKA) angle and muscle activation ratio between vastus medialis(VM), rectus femoris(RF), and vastus lateralis (VL), and by this, to examine their relationship. It is aimed to explore how the activation ratio among the muscles involved in patellofemoral kinetics would vary in relation with the frontal alignment of the lower extremity. Subjects and Methods: 26 healthy subjects were recruited for the study. The HKA angles were measured with radiograph. The VM, RF, VL muscle activation level were measured by surface electromyography while each participant performed 4 different types of movement (isometric knee extension, squat, ambulation, step-up) and VM/RF, VM/VL, RF/VL ratios were calculated. Pearson correlation was used to estimate the relationship between the HKA angle and the muscle ratio. Results: There was significant moderate correlation between HKA angle and VM: RF on the left side during ambulation (p<0.05). Moderate correlations were also observed during step-up and squat with less significance (p<0.1). Conclusion: The frontal alignment of the knee measured by the HKA angle was conditionally associated with muscle activation ratio between VM and RF (VM:RF); On the left, during ambulation, step-up, and squat, the more valgus knee tended to correlate with the more VM muscle activation ratio, which is expected to induce more stabilizing effect to the patella and its tracking. It suggests that the frontal alignement measured by the HKA-angle can affect PF kinetics. It also indicates a possibility that increase in valgus alignment of the knee, by the HKA measurement, may not act unfavorably to generate PFP.

• 국제물리치료학회지
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• 제11권2호
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• pp.2071-2076
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• 2020

Background: Based on the understanding of the muscle activation relationship between the infraspinatus and posterior deltoid muscles to according to the angle of motion during external rotation on glenohumeral joint, effective shoulder joint strengthening exercise for the prevention and rehabilitation of shoulder injury due to muscle strength imbalance can be performed by achieving the ideal muscle activity ratio during exercise. Objectives: To compare and analyze the muscle activation changes and activity ratio of the infraspinatus and posterior deltoid muscles according to the glenohumeral external rotation angle. Design: Quasi-randomized trial. Methods: The study included 48 healthy male and female adults who provided informed consent for participation in the study. All the subjects performed isometric glenohumeral external rotation by setting the angle of motion to 30°, 45°, and 60° using a 5 kg resistance weight pulley. On surface electromyography, the differences in muscle activation and activity ratio between the infraspinatus and posterior deltoid muscles were investigated. Results: A significant difference in muscle activation was found in the comparison between the infraspinatus and posterior deltoid muscles according to the glenohumeral external rotation angle (P<.05). The muscle activation levels of the infraspinatus and posterior deltoid muscles were highest at the external rotation angles of 30° and 60°, respectively. The muscle activity ratio between the infraspinatus and posterior deltoid muscles also showed a significant difference (P<.05) and was highest at the shoulder external rotation angle of 30°. Conclusion: The findings of this study suggest that muscle activity is the highest at the shoulder external rotation angle of 30° in healthy individuals.

• 대한물리의학회지
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• 제14권2호
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• pp.71-77
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• 2019

Purpose: The purpose of this study was to compare the level of muscle activation on the cervical erector spinae (CES), lumbar erector spinae (LES), and upper trapezius (UT) according to the sitting postures while using a smartphone in the bathroom. Method: Thirty-two healthy subjects were recruited for this study. The CES, LES, and UT were evaluated by surface electromyography according to two sitting postures while using a smartphone on the toilet seat. A paired t test was performed for the root mean square of reference voluntary contraction (%RVC) comparisons between two sitting postures, and one-way ANOVA was used to compare the three muscle activations within each posture. Results: A comparison between the two sitting postures revealed the muscle activation of both CESs in sitting posture 2 and both LESs in sitting posture 1 to be significantly higher than those of the others. In sitting posture 1, the muscle activation of both LESs was significantly higher than those of the CES and UT. In sitting posture 2, the muscle activation of both CESs was significantly higher than those of the LES and UT. Conclusion: High muscle activation of the CES and LES was observed according to the sitting postures when using smartphone in the restroom. Therefore, long time use of smartphones on a toilet seat should be avoided.

• 대한물리의학회지
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• 제6권3호
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• pp.311-321
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• 2011

Purpose : The purpose of this study was to determine effect of Medical Exercise therapy on walking ability and ankle muscles activation after stroke. Method : Participants were randomly divided into either MET training group(n=12) and control group(n=12). All of participants had been receving a traditional rehabilitation program, 5 days a week. MET training group have additionally undergone for six weeks, 3 days a week, the MET program. But control group was not received any additional program except the traditional rehabilitation program. The 10 mWT, F8WT and 2 MWT to measure walking ability were carried out twice before and after training. Muscular activity of the ankle was estimated by analyzing the RMS of action potential for EMG in terms of tibialis anterior muscle(TA), soleus(SO), gastrocnemius medial head(GM), gastrocnemius lateral head(GL). Rresults : At the walking ability, MET training group demonstrated a significant improvememt in the score of the 10 mWT(p<0.001), 2 MWT(p<0.05), but F8WT was not significant improvement(p>0.05). At the ankle muscle activation, MET training group demonstrated a significant improvememt in the RMS of the TA(p<0.01) and SO(p<0.05) but GM(p>0.05) and GL(p>0.05) were not significant improvement. Conclusion : From these results of this study, MET training for 6 weeks has an effect on improvement of walking ability and ankle muscles activation after stroke.

• 한국전문물리치료학회지
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• 제11권3호
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• pp.43-50
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• 2004

This study was designed to determine the effects of different widths in the base of support (BOS) on trunk and lower extremity muscle activation during upper extremity exercise. Twenty-seven healthy male subjects volunteered for this study. Exercises were performed for a total of 10 trials with a load of 10 repetitions maximum (10 RM) for each of the various widths of BOS (10 cm, 32 cm, 45 cm). The width of a BOS is the distance between each medial malleoli when a subject was in a comfortable standing position. Electromyography was used to determine muscle activation. Surface bipolar electrodes were applied over the tibialis anterior, medial gastrocnemius, biceps femoris, rectus femoris, gluteus maximus, upper rectus abdominis, and elector spinae muscle. Electromyographic (EMG) root mean square (RMS) signal intensity was normalized to 5 seconds of EMG obtained with a maximal voluntary isometric contraction (MVIC). The data were analyzed by atwo-factor analysis of variance (ANOVA) with repeated-measures ($3{\times}7$) and Bonferroni post hoc test. The results were as follows: (1) There were significant differences in the width of the BOS (p=.006). (2) The post hoc test showed significant differences with the BOS between 10 cm and 32 cm, between 10 cm and 45 cm and between 32 cm and 35 cm (p=.008, p=.003, p=.011). (3) There was no interaction with the BOS and muscle. (p=.438) There were no significant differences in the muscle activation (p=.215).

• 한국전문물리치료학회지
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• 제19권3호
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• pp.11-19
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• 2012

This study aimed to investigate whether isometric lower limb exercise can activate contralateral trunk muscles and whether the magnitude of muscle activation is related to lower limb movement in sitting. This study included 25 healthy young subjects (20 males and 5 females). The magnitude of trunk muscle activation was measured using surface electromyography (EMG) during hip flexion, extension, adduction, and abduction, and a significant difference was observed in the activation levels of trunk muscles among the tests (p<.01). The EMG activity of the multifidus (MF) and erector spinae (ES) muscles on the contralateral side were significantly greater during hip extension. However, the activation levels of the contralateral internal oblique (IO) and rectus abdominis (RA) muscles were greatest during hip flexion. The MF : ES EMG ratio was significantly greater during hip isometric during hip isometric flexion and abduction compared to hip extension and adduction. There was no significantly difference in the IO : RA ratio during the isometric contractions toward different directions. These findings indicate that isometric lower limb exercise can elicit trunk muscle contraction on the contralateral side and may therefore be helped for developing contralateral trunk muscle strength in individuals undergoing rehabilitation.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.46-53
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• 2017

Background: The MLA is supported by both the abductor hallucis (ABH) and the extrinsic muscles. Insufficient muscular support may lower the MLA when the body's weight is applied to the foot. The short foot exercise (SFE) is effective in increasing the height of the MLA for people with flat feet. Most of the research related to the SFE has simply evaluated the efficiency of the exercise using enhanced ABH electromyography (EMG) activation. Since the tibialis anterior (TA), peroneus longus (PER), and ABH are all involved in supporting the MLA, a new experiment design examining the EMG of the selected muscles during SFE should be applied to clarify its effect. Objects: Therefore, this study aimed to clarify the effect of the SFE in different ankle position on the MLA angle and the activation of both the intrinsic and extrinsic muscles and to determine the optimal position. Methods: 20 healthy subjects and 12 subjects with flat feet were recruited from Yonsei University. The surface EMG and camera were used to collect muscle activation amplitude of TA, PER, and ABH and to capture the image of MLA angle during SFE. The subjects performed the SFE while sitting in three different ankle positions-neutral (N), dorsiflexion (DF) at 30 degrees, and plantar flexion (PF) at 30 degrees. Results: ABH EMG amplitudes were significantly greater in N and DF than in PF (p<.05). Muscle activation ratio of TA to ABH was the lowest in PF (p<.05). MLA angle in both groups significantly decreased in PF (p<.01). The TA and ABH was activated at the highest level in DF. However, in PF, subjects significantly activated the ABH and PER with relatively low activation of TA. Conclusion: Therefore, researchers need to discuss which SFE condition most effectively use the arch support muscle for flat foot.

• Physical Therapy Rehabilitation Science
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• 제10권1호
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• pp.16-21
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• 2021

Objective: To control the rate at which body weight drops, forefoot initiates floor contact with the limb relatively extended at each joint. However, when the knee joints could not extend enough with going down the stairs, the forefoot cannot be contact initially. The purpose of this study was to investigate the differences between forefoot and whole foot in initial contract on soleus and tibialis anterior for health young adults when descending stairs. Design: A cross-sectional observational study design. Methods: Fifteen healthy young adults participated in this study. To compare between forefoot and whole foot in initial contact when going down the stairs, this study measured muscle activation on soleus and tibialis anterior. This study used the paired t-test to analyze the collected data and compare the supporting conditions. Results: After analyzing, the muscle activation of soleus was not statistically significant difference as 25.16% at forefoot initial contact and 24.37% at whole foot initial contact when descending stairs (p>0.05). However, the muscle activation of tibialis anterior muscle was significantly difference was 49.19% at forefoot contact and 71.55% at whole foot contact. Conclusions: The results of this study was that the muscle activation of the tibialis anterior was a higher at whole foot contact than that at fore foot contact when descending stairs. This study suggests that the landing strategy of the initial contact is a beneficial effect at the forefoot contact to maintain the postural balance and the muscle performance effectively when descending stairs in individuals with healthy young adults.