• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.1
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• pp.16-26
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• 2006

The purpose of this study was to investigate the influence of the various knee angles and ground state on the muscular activities and fatigue of the ankle muscles by integrated electromyograms (iEMG) and median frequency of tibialis anterior (TA), peroneus longus (PL), flexor digitorum longus (FDL) and gastrocnemius (GC). Ten healthy male subjects were participated into stable and balance ball sessions at four angles of knee joint. The surface electromyograms (sEMG) were recorded from the TA, PL, FDL and GC on stable and balance ball with full weight bearing at four knee angles of $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$. The time serial data of the surface electromyographic signals were transformed into integrated and frequency serial data by fast fourier transformation. On the stable ground, the iEMG signals of the TA, PL, FDL and GC were significantly higher at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee flexion (p<0.05). On the balance ball, the iEMG of the TA, PL, FDL and GC were significantly higher at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee flexion (p<0.05). The median frequency of the TA, PL, FDL and GC were significantly lower at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee on the stable ground (p<0.05). On the balance ball, also the median frequency of the TA, PL, FDL and GC were significantly lower at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee flexion (p<0.05). The iEMG of the TA, PL, FDL and GC were significantly higher on the balance ball at $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of knee angles compared with stable ground. The median frequency of the TA, PL, FDL and GC were significantly lower on the balance ball at $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of knee angles compared with stable ground. These results indicate that the ground conditions and angles of the knee joint involved to muscular activities and fatigue of ankles muscles, may performed at first on stable ground and then balance ball in order to $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of knee flexion.

• PNF and Movement
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• v.16 no.1
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• pp.43-50
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• 2018

Purpose: This study examined the effects of a shoulder-strengthening exercise on muscle strength of shoulder flexors and extensors of caregivers. Methods: The study consisted of 19 caregivers (2 males and 17 females) employed by Medical Center B. All the participants took part in an 8-week shoulder muscle strengthening exercise, based on previous studies. In the first week, the subjects took part in a stretching exercise enhance the range of motion. In the second week, they participated in an exercise aimed at improving shoulder blade stability. From the third to seventh weeks, a resistance exercise of different intensities was applied in a phased manner. Finally, in the eight week, the subjects took part in plyometric exercise. Peak torque, average power, and total work of shoulder flexors and extensors in both sides were measured before and after the exercise at an angular speed of 120deg/sec using an isokinetic device. Wilcoxon's singed-ranks test was conducted to analyze differences in muscle strength before and after the intervention. Results: After the exercise, there was a significant improvement in peak torque and average power of flexors of the right arm. After the exercise, peak torque, total work, and average power showed a significant improvement in the flexors of the left arm (p<0.05). However, there was no statistically significant difference in extensor muscle strength in either arm after the exercise. Conclusion: Shoulder flexors of caregivers are utilized frequently in the workplace. Implementation of extensor-strengthening exercises, in addition to flexor-strengthening exercises, can contribute to reducing the incidence rate of shoulder injuries among caregivers.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.347-357
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• 2009

The purpose of this study was to compare EMG and GRF during a free throw. Seven pairs of surface electrodes were attached to the right-hand side of the body to monitor the flexor carpi radialis (FC), extensor carpi radialis longus (EC), biceps brachii (BB), triceps brachii (TB), rectus femoris (RF), tibialis anterior (TA) and medial gastrocnemius (GM). GRF data from two force platform were collected during a free throw. The results showed that the muscle activities in the unskilled group must be highly activated prior to the moment of release. This means that a skilled participant can shoot a free throw more efficiently while producing less muscle activeness than an unskilled participant. The DCP of unskilled group in the medio-lateral direction were greater than the corresponding values in skilled group. This showed that the unskilled group were not able to shoot the free throws stably. Thus, when a teacher or instructor teaches students how to shoot free throw, it is considered that the teacher show the learner how to use not only the upper limbs but also lower limbs on the basis of the efficent connecting movement and the flexibility in a stable procedure.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.337-345
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• 2009

The purpose of this study were to find out the differences in kinematic variables of racket movement by performing the tennis serve. Three top male tennis players participated in this study. Three synchronized high-speed cameras were used to record the service action of top players for Three dimensional video analysis. The results of this study showed that (1) the velocity of the tennis racket at impact is important to the generation of racket velocity to Y-axis. This result indicates that forward motion and upward movement of the racket; (2) with respect to racket angular velocity at impact, the fast angular momentum of X-axis is important to generate the velocity of the tennis ball. This result indicate upward movement of the racket with a strong flexor of wrist joint; (3) the velocity of the tennis ball was influenced by the change of angular linking the Z-axis to -X-axis. This result indicates that the high velocity of the tennis ball is obtained from having the racket unitedly moving to the direction of the bill's flight at the acceleration interval and acquiring the distance of acceleration with the racket head vertically to the ground at the back scratching.

• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.437-442
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• 2013

Objective: The objective of this study was to investigate the effects of drive-assisting system in a shower carrier on the upper body muscle activities of caregivers through drivability tests. Background: In care facilities, one of the major ADL (Activities of Daily Living) factors is bathing/showering. Recently, bath/shower-assisting equipment is actively being introduced in care facilities to reduce caregivers' muscle burden. In particular, it is desirable to utilize a shower carrier equipped with drive-assisting system to effectively care for the elderly. However, there were few systematic studies on the relationship between muscle activities and drive-assisting speeds. Method: For the drivability tests to study the effects on the muscle activities according to the drive-assisting speeds(corresponding drive-voltages: 0.0V, 2.0V, 2.1V, 2.3V), 6 females in their 40s($43{\pm}4yrs$, $157{\pm}5cm$, and $54.5{\pm}1.5kg$) were selected. To measure muscle activities of caregivers through drivability tests, 7 muscles in the upper body(TM/Trapezius Muscle, DM/Deltoid Muscle, BBM/Biceps Brachii Muscle, TBM/Triceps Brachii Muscle, ECRLM/Extensor Carpi Radialis Longus Muscle, FCUM/Flexor Carpi Ulnaris Muscle, and ESM/Erector Spinae Muscle) were selected. Results: In the TM, muscle activities were decreased as 21% compared to 0.0V, when drive-voltage 2.0V was applied, as 57% by 2.1V, and 62% by 2.3V(p<0.05), whereas 40%, 56%, and 69% of muscles activities were decreased respectively from the DM(p<0.05). Also, from the UL(BBM+TBM+ECRLM+FCUM), muscle activities were decreased by 17% with 2.0V as against 0.0V, by 47% with 2.1V, and 52% with 2.3V, whereas decreases in muscle activities from the ESM were found by 20%, 34%, and 42% respectively by 2.0V, 2.1V, and 2.3V(p<0.05). Conclusion: The muscle activities were decreased in the order of the DM, TM, ESM, and UL. As muscle activities were remarkably reduced as drive voltage were increased, it was expected to reduce the upper body muscle burden on the caregivers when using shower carriers equipped with driving-assist system. Applications: The results from this study can be applied for the development of a shower carrier including other equipment to possibly reduce the muscle burden of the caregivers.

• Physical Therapy Korea
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• v.16 no.3
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• pp.9-15
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• 2009

The purpose of this study was to examine contraction of abdominal muscles on surface electromyographic (EMG) activity of superficial cervical flexors, rib cage elevation and angle of craniocervical flexion during deep cervical flexion exercise in supine position. Fifteen healthy subjects were participated for this study. All subjects performed deer cervical flexion exercise with two methods. The positions of two methods were no volitional contraction of abdominal muscles in hook-lying position with 45 degree hip flexion (method 1) and 90 degrees hip and knee flexion with feet off floor for inducing abdominal muscle contraction (method 2). Surface EMG activities were recorded from five muscles (sternocleidmastoid, anterior scaleneus, recuts abdominis, external oblique, internal oblique). And distance of rib cage elevation and angle of craniocervical flexion were measured using a three dimensional motion analysis system. The EMG activity of each muscle was normalized to the value of reference voluntary contraction (%RVC). The EMG activities, distance of rib cage elevation. and angle of craniocervical were compared using a paired t-test between two methods. The results showed that the EMG activities of sternocleidmastoid and anterior scaleneus during deep cervical flexion exercise in method 2 were significantly decreased compared to method 1 (p<.05). Distance of rib cage elevation and angle of craniocervical flexion were significantly decreased in method 2 (p<.05). The findings of this study indicated that deep cervical flexion exercise with contraction of abdominal muscles could be an effective method to prevent substitute motion for rib cage elevation and contraction of superficial neck flexor muscles.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.471-478
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• 2004

Electromyogram (EMC) signal generated by voluntary contraction of muscles is often used in a rehabilitation devices such as an upper limb prosthesis because of its distinct output characteristics compared to other bio-signals. This paper proposes an EMG-based human-computer interface (HCI) for the control of the above-elbow prosthesis or the wheelchair. To control such rehabilitation devices, user generates four commands by combining voluntary contraction of two different muscles such as levator scapulae muscles and flexor-extensor carpi ulnaris muscles. The muscle contraction is detected by comparing the mean absolute value of the EMG signal with a preset threshold value. However. since the time difference in muscle firing can occur when the patient tries simultaneous co-contraction of two muscles, it is difficult to determine whether the patient's intention is co-contraction. Hence, the use of the comparison method using a single threshold value is not feasible for recognizing such co-contraction motion. Here, we propose a novel method using double threshold values composed of a primary threshold and an auxiliary threshold. Using the double threshold method, the co-contraction state is easily detected, and diverse interface commands can be used for the EMG-based HCI. The experimental results with real-time EMG processing showed that the double threshold method is feasible for the EMG-based HCI to control the myoelectric prosthetic hand and the powered wheelchair.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.284-290
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• 2020

This study was undertaken to determine the effects of SNAGs (sustained natural apophyseal glides) and visual convergence biofeedback on the proprioception and neck disability of patients with chronic neck dysfunction. A total of 31 patients with neck dysfunction were assigned to either SNAGs (n = 16) or biofeedback (n = 15). The groups were assessed for proprioception and neck disability, before and after the intervention. The SNAGs were performed using belt with flexion, extension and right-left rotation, whereas biofeedback training included visual feedback training with deep neck flexor. Intervention was implemented for 20 minutes, twice a week for 4 weeks. Biofeedback training a showed significant effect on the joint position sense (left and right rotation) as compared to the SNAGs group (p< 0.05), whereas neck disability index was significantly effective for SNAGs (p< 0.05). Ed. Notes: The previous statement lacked clarity. I have suggested the edit as per my understanding. Please review and revise appropriately, if required. Therefore, the SNAGs technique is effective for neck function, and biofeedback training is a positive intervention method for enhancing the proprioceptive sensation. In future studies on patients with neck pain, it may be possible to select an intervention method based on the characteristics of the disease.

• The Journal of Korean Physical Therapy
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• v.14 no.2
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• pp.162-171
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• 2002

The purpose of this study was to examined whether high voltage pulsed current stimulation(HVPCS) enhances the migration and proliferation of fibroblasts from tendon biopsies to provides evidence that the cellular activities of fibroblast are enhanced by HVPCS. Flexor digitorum profundus tendon of chickens were excised, biopsied and cultured in M199 medium for a day. The biopsies through which a cathodal HVPC with 100 pps, 50 V for 30 minutes was passed in medium. A day after treatment, the biopsies embedded in fibrin clot were covered by the addition of 1ml of M199 medium to the well, and placed in the $CO_2$ incubator for the duration of the experiment. The migration distance of cells from tendon biopsies were measured at 6 days after treatment, and proliferation of cells from tendon biopsies were measured at 7 days after treatment. The migration distance of cells from tendon biopsies in the HVPCS group demonstrated significantly greater than the shame treated control group (t=-2.675, p<0.05). Also HVPCS had significantly increased optical density of fibroblasts from tendon biopsies (t=-2.136, p<0.05). These results indicate that the HVPCS with 100pps, 50V for 30minutes enhanced either the migration and proliferation of fibroblast from tendon biopsies. These results supposed that the HVPCS activates cellular responses in fibroblasts from tendon biopsies. This suggests that enhanced the migration and proliferation of fibroblast by HVPCS may be one of the mechanism involved in tendon healing.

• The Journal of Korean Physical Therapy
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• v.23 no.1
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• pp.21-28
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• 2011

Purpose: The aim of this study was to investigate correlations between the Functional Movement Screen (FMS), pain, and performance ability in professional fencing players. Methods: Fifty-six athletes participated in this study. The pain group included those who had a score on a pain-related Visual Analogue Scale (VAS) of ${\geq}$20 and an Oswestry Disability Index (ODI) score ${\geq}$10). In the non-pain group, these scores were: VAS(<20), ODI(<10). The VAS and ODI were used to measure pain throughout the study. Performance ability included motor function of the lower extremities (as assessed by a Modified Functional Index Questionnaire, MFIQ), dynamic balance (Balance system, BS and Posture med, PM), flexor and extensor muscle strength of the lumbar region was recorded as maximal isometric strength. Results: Among athletes who had pain, 5 of 15(33.33%) showed impaired functional movement. Conversely, only 2 of 41(4.88%) of those who had no pain showed such impairment (FMS ${\leq}$14score). The athletes who had pain and who had an FMS score above 14 (10/56; 17.86%) showed a significantly higher score for extensor muscle strength of the lumbar compared with those with pain and an FMS score below 14 (5/56; 8.93%) were significant correlations between the FMS and pain (r=-0.40 to -0.42, p<0.01), the MFIQ (r=-0.33, p<0.05), dynamic balance (r=-0.27 to -0.40, p<0.05-0.01), muscle strength of the lumbar (r=0.27 to 0.29, p<0.05). Stepwise multiple regression analysis showed that the dynamic balance score (${\beta}{\beta}$=-0.41) had slightly more power in predicting FMS score than pain, motor function of lower extremity, or muscle strength. Conclusion: The FMS was significantly associated with values of pain, motor function of the lower extremities, dynamic balance, and muscle strength of the lumbar. However the FMS appears to lack relevance and reasonable evidence to suggest that it is an acceptable measurement tool for functional movement analysis.