• 한국전문물리치료학회지
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• 제15권1호
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• pp.46-53
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• 2008

The aim of the present study was to determine the effect of proprioceptive neuromuscular facilitation (PNF) leg patterns on the muscle activation of neck flexors. Twenty healthy subjects participated in this study. Each subject performed bilateral asymmetrical PNF leg patterns against manual resistance under four conditions: through the full range of motion toward the right side, left side, and the end range in the right side, left side. Electromyographic (EMG) data was collected from the sternocleidomastoid (SCM) muscles as neck flexors. The root mean square (RMS) value of the SCM was measured and normalized from maximal EMG activity of the SCM. The data were analyzed using the paired t-test and repeated analysis of variance (ANOV A) was used to compare the statistical significance. The results of this study are summarized as follows: Firstly, the RMS values of SCM were significantly higher in all four PNF leg patterns than in the resting condition (p<.05). Secondly, there was no significant difference in muscle activation according to the direction of PNF leg patterns (p>.05). Thirdly, there was no significant difference in muscle activation according to the point of range of the motion of leg patterns (p>.05). It is suggested that PNF bilateral asymmetrical leg patterns have a considerable effect on muscle activation of the SCM, regardless of the range of motion and direction of PNF bilateral asymmetrical leg patterns.

• 한국전문물리치료학회지
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• 제24권1호
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• pp.86-96
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• 2017

Background: Scapular dyskinesis is characterized by altered scapular position and motion. Specifically, excess activation of the Upper trapezius (UT) combined with decreased Lower trapezius (LT) and Serratus anterior (SA) have been observed. The Standard push-up plus exercise (SPP) is considered as a therapeutic exercise for increasing SA activity and maintaining the scapular kinematics. In addition, Using the Sling surface can lead to higher muscle activity. However, the advantage of an unstable surface has been uncertatin. Objects: To compare the activation of the UT, LT, and lower serratus anterior (LSA) muscles during various push-up plus exercises with and without sling in subjects with scapular dyskinesis. Methods: Total 18 male subjects with scapular dyskinesis were recruited. The UT, LT, and LSA electromyographic activities and the UT/LSA and UT/LT EMG activity ratios were measured during three push-up plus exercises with and without sling. Two-way repeated of analysis of variance was used to determine the statistical significance. Results: The UT activity was significantly lower in all postures without sling than that with sling. In addition, the LSA activity was significantly greater without than with sling, and significantly large in SPP, Low back supported push-up plus (LSPP), and Quadruped push-up plus. Additionally, the UT/LSA and UT/LT activity ratios were lower in SPP and LSPP without sling than with the other four push-up plus exercises. Conclusion: The push-up plus without sling were considered to decrease UT and increase LSA activity compared with exercises with sling. Furthermore, SPP without sling seems to be a more effective exercise for increasing LSA activity and lowering the UT/LSA and UT/LT activity ratios in scapular dyskinesis subjects.

• 한국전문물리치료학회지
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• 제22권4호
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• pp.17-26
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• 2015

The purpose of this study was to investigate the effects of visual electromyography (EMG) biofeedback on the EMG activity of the lower trapezius (LT), serratus anterior (SA), and upper trapezius (UT) muscles, the LT/UT and SA/UT EMG activity ratios, and the scapular upward rotation angle during scapular posterior tilting exercise (SPTE). Twenty-four subjects with round-shoulder posture participated in this study. The EMG activities of the LT, SA, and UT were collected during SPTE both without and with visual EMG biofeedback. The scapular upward rotation angle was measured at the baseline, after SPTE without visual EMG biofeedback, and after SPTE with visual EMG biofeedback. The LT, SA, and UT EMG activities, and the LT/UT and SA/UT EMG activity ratios were analyzed by paired t-test. The scapular upward rotation angle was statistically analyzed using one-way repeated analysis of variance. If a significant difference was found, a Bonferroni correction was performed (p=.05/3=.017). The EMG activities of LT and SA significantly increased, and the EMG activity of UT significantly decreased during SPTE with visual EMG biofeedback compared to SPTE without visual EMG biofeedback (p<.05). In addition, the LT/UT and SA/UT EMG activity ratios significantly increased during SPTE with visual EMG biofeedback compared to SPTE without visual EMG biofeedback (p<.05). Significant increases were found in the scapular upward rotation angle after SPTE without and with visual EMG biofeedback compared to baseline (p<.017), and no significant differences were observed in the scapular upward rotation angle between SPTE without and with visual EMG biofeedback. In conclusion, SPTE using visual EMG biofeedback may be an effective method for increasing LT and SA activities while reducing UT activity.

• 대한인간공학회지
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• 제34권1호
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• pp.1-10
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• 2015

Objective: The purpose of this paper is to evaluate old and newly designed ammunition boxes from an ergonomic point of view. Background: The ammunition boxes made of wood, which are currently used by the military, have some difficulties such as corrosion and damage of ammunition, environmental pollution, and stock management. Also, damages to the wooden ammunition boxes take place frequently, because soldiers carry them manually. Method: Sixteen participants volunteered to randomly perform lifting, carrying, and side-by-side moving tasks with 4 different old and new boxes, respectively for the ammunitions of 5.56mm, 60mm, 81mm, and 105mm in diameter. The old boxes are made of wood and are currently used in the military, while the new boxes are made of plastics. The joint moments of the elbow, shoulder, back, and knee were measured by using a motion analysis system and force platforms. In addition, an electromyographic system was used to measure the forces of hand and wrist muscles. Results: In most tasks, new boxes caused less joint moments at the elbow and shoulder than old boxes, because the new boxes were lighter and smaller than the old boxes. New boxes also derived less hand and wrist muscle forces due to the provision of fixed hard handles rather than string handles. Conclusion: The ergonomically designed new boxes could reduce the physical stresses of soldiers manually handling ammunitions and be helpful for storage and reuse. Application: This study shows an ergonomic application example for product development and evaluation.

• PNF and Movement
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• 제17권3호
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• pp.441-450
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• 2019

Purpose: This study identified the co-activation of quadriceps and hamstring muscles during hamstring strengthening exercises in healthy adults. Methods: Twenty-one participants were required for the present study design to achieve 80% power, 0.8 effect size (η2), and an alpha level of 0.05. Thus, this study recruited 21 healthy adults. All participants performed Nordic exercises, bridge exercises, and one-leg deadlifts randomly. The activity of the rectus femoris, vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), and semitendinosus (SM) were measured. In addition, the ratios of VM/VL and hamstring/quadriceps (HQ) were measured during the three hamstring strengthening exercises using electromyography. One-way ANOVA was used to compare the co-activation of quadriceps and hamstring muscles in the three exercises. Results: The activity of VM and VL during the performance of one-leg deadlifts was significantly higher than the other two exercises. The BF had significantly higher activity during the Nordic exercises compared to the other two exercises. In addition, the SM activation was significantly greater during Nordic exercises than one-leg deadlifts. Additionally, there was significant difference in HQ ratio among hamstring strengthening exercises. In specific, the one-leg deadlifts yielded a significantly lower HQ ratio. Conclusion: This study revealed that one-leg deadlifts are effective in rehabilitation for anterior cruciate ligament injury. In addition, Nordic exercises can be recommended to facilitate hamstring muscle activation.

• 한국전문물리치료학회지
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• 제13권1호
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• pp.24-31
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• 2006

The purpose of this study was to identify the effect of the hip internal rotation on gluteal and erector spinae muscle electromyographic (EMG) activity during treadmill walking. Eleven healthy subjects were recruited. All subjects performed treadmill walking while maintaining the hip in neutral position (condition 1) and in internal rotation (condition 2). Surface EMG activity was recorded from four muscles (gluteus maximus (GM), gluteus medius (GMED), tensor fascia latae (TFL), and erector spinae (ES)) and the hip internal rotation angle was measured using a three dimensional motion analysis system. The gait cycle was determined with two foot switches, and stance phase was normalized as 100% stance phase (SP) for each condition using the MatLab 7.0 program. The normalized EMG activities according to the hip rotation (neutral or internal rotation) were compared using a paired t-test. During the entire SP of treadmill walking, the EMG activities of GM in condition 1 were significantly greater than in condition 2 (p<.05). The EMG activities of TFL and ES in condition 2 were significantly greater than in condition 1 (p<.05). The EMG activities of the GMED in condition 1 were significantly greater than in condition 1 (p>.05) except for 80~100% SP. Further studies need randomized control trials regarding the effect of hip internal rotation on the hip and lumbar spine muscle activity. Kinetic variables during gait or going up and down stairs are also needed.

• The Journal of Korean Physical Therapy
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• 제2권1호
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• pp.35-46
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• 1990

The right hip adbuctor musculature has been reported to demonstrate 'stretch weakness' attributable to chronic elongation imposed by standing posture common to right-handed healthy persons. Kendall and associates have described the concept of 'stretch weakness'. The purpose of this study was to assess isometric hip abduction torque and surface electro-myographic activity (using MYOMED 432) in a sample of 40 healthy right-handed persons (20 male, 20 female), all of whom agreed to participate in the study, and compare side difference in the hip abductor musculature. In order to assure the statistical significance of the results, the paired t-test was applied at the .05 level of significance. The results were as follows : 1. The difference in apparent leg length of right and left legs was significant at the .05 leve1. 2. There was a significant difference between right and left pelvic height (standing position) at the .005 level measurements, and scapula height at the .05 level. 3. Power measurements and action potentials of right hip adbuctor were greater than the left hip adbuctor regardless of the range of joint motion (inner range, outer range). 4. The difference in muscle power and action potentials according to inner or outer range of both hip abductor were significant at the .05 level. 5. In supine during active left hip abduction, the appearance of action potentials in the right hip abductors is indicative of contra-lateral effect (p<.005). These results suggest : In healthy right-handed persons. the apparent leg length on the right is longer than on the left, and pelvic height is elevated on the right side. Muscle torque and muscle action potentials of the right hip adbuctor art higher than those of the hip abductor in the lengthened position. Therefore, the results in this study are contrary to Kendall's. This type of study should be carried out in many physical therapy departments.

• PNF and Movement
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• 제19권1호
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• pp.79-86
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• 2021

Purpose: The purpose of this study was to investigate muscle activity according to knee flexion angle during single-limb-deadlift exercises. Methods: In total, 26 healthy volunteers participated. The single-limb-deadlift consisted of 0˚, 15˚, and 30˚ knee joint bending. The electromyography data were collected from the semitendinosus (SM), the biceps femoris (BF), the rectus femoris (RF), the vastus lateralis (VL), and the vastus medialis (VM). In addition, hamstrings and quadriceps (HQ) ratio was measured during the single-limb-deadlift using electromyography. Results: During the single-limb-deadlift, RF, VL, and VM were significantly higher at 30˚ bending angles compared to muscle activity of 0˚ and 15˚ knee-joint bending. The HQ ratio had significant differences in all three knee joint bending angles. In particular, the single-limb-deadlift carried out to a 30˚ knee-joint bend showed the closest value to 1. Conclusion: The most balanced coactivation ratios were observed during a single-limb-deadlift to a 30˚ knee-joint bend angle. A single-limb-deadlift at a knee-bend angle of less than 30˚ could be used as an exercise to prevent ACL injury. It could also be used for post-injury rehabilitation programs by increasing knee-joint stability.

• 한국전문물리치료학회지
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• 제26권3호
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• pp.91-98
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• 2019

Background: The bridge exercise targets the gluteus maximus (Gmax) and gluteus medius (Gmed). However, there is also a risk of dominant hamstring (HAM) and erector spinae (ES) muscles. Objects: To analyze the muscle activity the of Gmax, Gmed, HAM and ES during the bridge exercise with and without hip external rotation in different degrees of knee flexion. Methods: Twenty-three subjects were participated. The electormyography (EMG) activity of the Gmax, Gmed, HAM and ES muscles was recorded during the exercise. The subjects performed the bridge exercise under four different conditions: (a) with $90^{\circ}$ knee flexion, without hip external rotation (b) with $90^{\circ}$ knee flexion, with hip external rotation (c) with $135^{\circ}$ knee flexion, without hip external rotation (d) with $135^{\circ}$ knee flexion, with hip external rotation. Results: There was no significant interaction effect between the degree of knee flexion and hip external rotation. There was a significant main effect for degree of knee flexion in Gmax, HAM muscles activity. Gmax muscle activity was significantly greater in the $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p<.001). While HAM muscle activity was significantly less in $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p<.001). ES muscle activity was significantly less in the $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p=.002). The activity of both the Gmax and Gmed muscles was significantly greater with hip external rotation (p<.001 and p=.005, respectively). Conclusion: For patients performing the bridge exercise, positioning the knee in $135^{\circ}$ of flexion with hip external rotation is effective for improving Gmax and Gmed muscle activity while decreasing HAM, and ES muscle activity.

• 한국전문물리치료학회지
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• 제29권2호
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• pp.147-155
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• 2022

Background: Although various conventional approaches have been employed to reduce spasticity in neurological rehabilitation, only a few studies have shown scientific evidence for its effectiveness. Thus, we introduced a different concept (Ueda method) of rehabilitation therapy that can complement the limitations of conventional therapy. Objects: This study aimed to investigate the immediate effects of the application of the Ueda method on patients with spasticity after stroke via an electrophysiological study. Methods: We conducted a randomized double-blind pilot study in two rehabilitation hospitals involving 30 stroke patients who were randomly allocated to the Ueda (n = 15) and convention (n = 15) groups. Electromyographic data of six examined muscles in both upper extremities of all patients were recorded. The A-ApA index and activation ratios of upper extremity muscles were evaluated and compared between the groups to confirm post-intervention changes in upper-extremity flexor spasticity and flexion synergies. Repeated-measures analysis of variance was conducted to confirm the therapeutic effect (2 × 2) as a function of group (Ueda vs. convention) and time (pre-/post-intervention) on all outcome measures (p < 0.05). Results: In the Ueda group, the mean A-ApA index values differed significantly before and after the intervention (p = 0.041), indicating a weak evidence level; however, the effect size was medium (d = -0.503). The interaction effects of the A-ApA index between the Ueda and convention groups and between pre-intervention and post-intervention stages were significant (p = 0.012). The effect size was large (n_p² = 0.220). In the Ueda group, the activation ratios of the anterior deltoid fiber significantly decreased after the intervention in all reaching tasks. Conclusion: The Ueda method reduces upper-extremity flexor spasticity and changes its synergy in stroke patients and should be considered a rehabilitation therapy for spastic stroke patients.