• Physical Therapy Rehabilitation Science
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• v.8 no.2
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• pp.86-92
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• 2019

Objective: The purpose of this study was to compare the effects of performing squats and kneeling squats on trunk and lower extremity muscle activity in persons with stroke. Design: Cross-sectional study. Methods: Ten persons with stroke (3 male and 7 female) were recruited. The subjects were instructed to randomly perform the 4 different squat conditions: squat with 30 degrees of knee flexion, squat with 60 degrees of knee flexion, squat with 90 degree of knee flexion, and the kneeling squat. During the squat performance, surface electromyograms (sEMG) was used to assess muscle activity of the erector spinae (ES), gluteus maximus (Gmax), gluteus medius (Gmed), and biceps femoris (BF) muscles. Results: Muscle activation of the ES and BF were significantly increased with the kneeling squats compared to the general squats with 30 degrees and 60 degrees of knee flexion (p<0.05), and muscle activation of the Gmax and Gmed were significantly increased with the kneeling squats compared to all other squat conditions (p<0.05). Conclusions: The results suggest that the kneeling squat is an effective exercise to strengthen the proximal muscles of the lower extremities. Rather than applying a difficult general squat to the stroke population, the kneeling squat may be applied as a safer method for training the proximal muscles.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.133-139
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• 2019

Purpose : This study aims to investigate the rating of perceived exertion (RPE) and muscle activity of the inspiratory primary and accessory muscle during breathing exercise with different air hole diameters of the inspiratory muscle trainer (IMT). Methods : The Borg's scale and surface electromyography (EMG) was used to collect data of the RPE and muscle activity of the inspiratory primary the external intercostal (EI) and diaphragm (DIA) and accessory muscles anterior scalene (AS), sternocleidomastoid (SCM), pectoralis major (PM), and upper trapezius (UT) muscles during breathing exercise with different air hole diameters (6 mm, 4 mm, and 2 mm) of the IMT in healthy young male subjects. Results : The RPE and muscle activities of the AS, SCM, and UT are increased significantly in accordance to the decreasing diameter of air hole of air tip in IMT. However, there are no differences in the muscle activities of the PM, EI, and DIA based on differences of diameters of air hole of air tip in IMT. Conclusion : The smaller the diametr of IMT air-hole, RPE and muscle activities of AS, SCM and UT were increased. Therefore, further study would be necessary to investigate the proper intensity and relaxation posture for the exercise protocol to strengthen the inspiratory primary muscles.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.139-149
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• 2014

The purpose of this study was to evaluate the effect of angle change of forefoot's adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over $-20^{\circ}$ ramp. Thirteen male university students (age: $25.4{\pm}3.9$ yrs, height: $176.2{\pm}5.1$ cm, weight: $717.4{\pm}105.0$ N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site pre-amplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over $0^{\circ}$ and $20^{\circ}$ ramp with three different forefeet's EVA outsole (0, 10, $20^{\circ}$) in random order at a speed of $1.2{\pm}0.1$ m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in $20^{\circ}$ shoes compared to $0^{\circ}$ and $10^{\circ}$ ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot's adhesive outsole, indicating that the increment of shoes' angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in $20^{\circ}$ outsole compared to $0^{\circ}$ and $10^{\circ}$ ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.678-683
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• 2016

The study aim was to investigate a comparison of muscle activity fatigue between maximal and submaximal strength gains during the bench press in men. It was hypothesized that maximal voluntary contraction (%MVC) would similar gains between maximal and submaximal strength gains during the bench press, but median frequency (MDF) would increase in maximal compared with submaximal exercise. Employing a randomized, counterbalanced crossover design, 12 men were asked to perform maximal repetitions and submaximal repetitions (concentric: 1-s, eccentric: 1-s, 2-s/repetition) to failure with a load of 85% of 1RM for the bench press, with a 3-minute recovery between the sets. Each subject was tested for the number of repetitions and sets, total work in bench press. Surface electromyography (EMG) was recorded from the pectoralis major, deltoid anterior, and triceps brachii for %MVC and MDF. Total work was significantly higher in the submaximal repetition exercise than that the maximal repetition exercise (p<.05). Muscle fatigue of pectoralis major, deltoid anterior and triceps brachii were significantly smaller in the submaximnal repetition exercise than that the maximal repetition exercise (p<.05, respectively). However, muscle activity of pectoralis major, deltoid anterior, and triceps brachii were not significantly different between exercises. Our study showed that a smaller muscle fatigue in submaximal repetitions, despite higher in total work and a similar in muscle activity were observed. These results suggest that submaximal repetitions during the bench press would be enhanced intensity and/or volume compared with maximal repetitions exercise.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.1
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• pp.13-19
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• 2013

The aim of this study was to investigate difference of the muscle activation patterns of the upper body during wheelchair cycle ramps ascent of different slopes for disabled with spinal cord injury. Three subjects who is disabled with spinal cord injury participated in this study. Surface electromyography (EMG) data (reaction time [RT], onset-offset time, and peak value of muscle activation) were collected biceps, triceps, upper trapezius, anterior deltoid, latissimus dorsi, and upper rectus abdominal muscles during wheelchair cycle ramps ascent ($0^{\circ}$, $3^{\circ}$, and $6^{\circ}$). For latissimus dorsi muscle, RT and peak value of muscle activation was were increased and offset time was delayed as the slope increased (p < 0.05). These results indicate that wheelchair cycle ramps ascent might cause excessive overuse of latissimus dorsi muscle.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.209-216
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• 2018

This study aimed to investigate the association of the muscle activity around the neck of the operator(dental hygienists') according to the change in the patient's neck angle during a direct visual inspection on the maxillary right-side molar palatal surface. The operators were $4^{th}$ year dental hygiene students, who are future dentalhy gienists, having accurate understanding on and awareness of the location of the operation site, hand fixation, and how to use the tools. Data on the change in the muscle activity around the neck were collected by using surface electromyography and neck goniometer. SPSS statistics 20 was used for statistical analyses including Shapiro-wilk test and one-way ANOVA. As a result, the activities of the operator upper trapezius, cervical erector spinae, and levator scapulae muscles significantly decreased when the patient's head was angled compared to when it was not. For the angle of the operator head, the head bend significantly decreased when the patient's head was angled than when it was not. Based on the study results, it is expected that angling the patient's head when treating his or her teeth will decrease the excessive muscle activity around the neck of the operator, and will reduce muscle fatigue. Therefore, angling the head of the patient while treating his or her teeth is recommended. This suggests that muscle pain caused by repetitive actions in the wrong posture can be reduced.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.1
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• pp.129-136
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• 2018

PURPOSE: This Study compared the level of activation of the muscles around the shoulder at the time of abduction through Pilates breathing and regular breathing by using quantified biofeedback. METHODS: Experiment was conducted on 25 healthy males and females in the age bracket of 20's~30's as the subjects. The level of activation of muscles displayed at the time of Pilates breathing were measured at intercostal (InC) muscle, transverse abdominis (TrA) muscle, internal oblique (IO) muscle and external oblique (EO) muscle by using surface electromyogram (EMG) and were provided as biofeedback. Moreover, the changes in the level of muscular activation at sternocleidomastoid (SCM) muscle, upper trapezius (UT) muscle and Deltoid (Del) muscle, which are the muscles around the shoulder, at the time of abduction of shoulder during Pilates breathing and regular breathing were measured. RESULTS: When abduction of shoulder is executed through Pilates breathing, the level of muscular activation of UT muscle was $11.56{\pm}7.10%$ at the time of exhaling of Pilates breathing and $17.54{\pm}9.57%$ at the time of exhaling of regular breathing. Del muscle also displayed lowered level of muscular activation at the time of Pilates breathing with $12.88{\pm}5.80%$ during inhaling and $15.14{\pm}5.49%$ during exhaling. CONCLUSION: In conclusion, the results could be interpreted as indicating that the muscle activities of upper trapezius and deltoid muscle were decreased based on Pilates breathing more than those on regular breathing.

• PNF and Movement
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• v.16 no.1
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• pp.33-42
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• 2018

Purpose: The aim of this study was to investigate the effects of trapezius and serratus anterior strengthening exercise on the shoulder pain and muscle activation of patients with spinal cord injury and functional shoulder impingement syndrome. Methods: The study consisted of 10 patients with spinal cord injury who were hospitalized in Rehabilitation Hospital U, Uijeongbu, South Korea. The exercise was implemented three times a week for 10 weeks. In each session, the subjects performed one of a total of five types of exercise at mid-level intensity. The shoulder pain and disability index (SPADI) was used to evaluate the patients before and after the intervention. The muscle activation of the upper trapezius, middle trapezius, lower trapezius, and anterior serratus muscle was assessed by surface electromyography (EMG) at the beginning of the experiment and 10 weeks later. Wilcoxon's singed-rank test was conducted to determine differences in the pain index and muscle activation before and after the exercise. The level of statistical significance was set at ${\alpha}=0.05$. Results: SPADI scores significantly decreased after the exercise (p<0.05). In comparisons of muscle activation, there was a significant improvement in the upper trapezius at $60^{\circ}$ shoulder joint flexion (p<0.05). There was no significant improvement at $90^{\circ}$ shoulder joint flexion. The middle trapezius showed a significant improvement at $120^{\circ}$ shoulder joint flexion (p<0.05). Conclusion: Trapezius and serratus anterior strengthening exercise reduced pain in spinal cord injury patients with functional shoulder impingement syndrome. The decreased muscle activation of upper trapezius and increased muscle activation of the anterior serratus muscle at $60^{\circ}$ shoulder joint flexion point to positive effects of the exercise on supraduction of the scapula.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.91-99
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• 2013

The purpose of this study was to investigate the muscular activity and muscle strength for swing track of upper limbs during rowing exercise. Subject was all twenty healthy adults and they were divided into linear exercise group and elliptical exercise group in random. Subjects performed rowing exercise 3-times for a week and performed all 8-weeks. We measured realtime-surface EMG. Also we measured joint torque of elbow, ankle and lumbar in subjects using BIODEX. The result showed that when rowing exercise, elliptical track exercise had higher muscular activity in trapezius, deltoid, erector spinae, rectus femoris, biceps femoris, gastronemius than linear track exercise on more many muscle of upper and lower limbs. Also elbow joint torque and lumbar joint torque was more higher too. but linear exercise also had higher muscular activity in multifidus, tibilalis anterior than elliptical track exercise. According to this experiment, we found out that elliptical track was more efficient than linear track.

• The Journal of Korean Physical Therapy
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• v.26 no.1
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• pp.9-14
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• 2014

Purpose: The purpose of this study was to investigate how different knee alignments (genu varum and genu valgum) affected activations of quadriceps muscles with measurements of onset-time differences between vastus medialis and vastus lateralis during isometric contractions at both 30 and 60 degree knee flexion. Methods: Fifty-two adults (20 genu varum, 12 genu valgum, and 20 control) were enrolled in this study. Subjects with over 4cm distance between knee medial epicondyles were assigned to Genu varum, while subjects with over 4cm distance between ankles medial malleolus were considered as genu valgum group. Surface EMG was used to measure onset time of both vastus medialis and vastus lateralis during isometric contraction at 30 and 60 degree knee flexion. Results: The onset time of vastus lateralis was delayed in genu varum group, and that of vastus medialis was delayed in genu valgum group at both 30 and 60 degree knee flexions. Moreover, onset time difference at $30^{\circ}$ knee flexion between muscles was larger in genu valgum group than genu varum group. Conclusion: Subjects with genu varum or valgum activated quadriceps muscles with different orders pending on flexion degrees. Therefore, when quadriceps training program were planned to prevent pain or deformities, the findings that quadriceps were activated with different orders affected by knee alignments and joint degree at which trainings were performed, must be considered. If the selective training programs of quadriceps femoris are planned to prevent pain or deformities due to poor knee alignments, these should consider the subject's knee alignment condition.