• The Journal of Korean Physical Therapy
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• v.19 no.6
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• pp.17-22
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• 2007

Purpose: To evaluate the quantitative isometric muscle strength of shoulder girdle and the test reliability using by the equipment, named 'IsoTrack', selected by authors in the former studies. Methods: Thirty healthy subjects (9 men, 21 women) were recruited in two sessions, one for intratester and intertester reliability tests and the other quantitative isometric muscle strength tests. The neck flexion, extension and scapular elevation muscle strength was measured using a force measuring device as IsoTract. Results: Intraclass correlation coefficients for intratester reliability of the all subjects ranging between 0.96 and 0.97. For intertester reliability, the ICC and Pearson correlation correspond to 0.84 and 0.78. We gauged muscle strength of shoulder girdle muscles based on it and indicated quantified isometric muscle strength of women and men in left and right side. Conclusion: We concluded that there were high reiliability of isometric muscle strength of neck and shoulder girdle. Also, we gauged muscle strength of shoulder girdle muscles based on it and indicated quantified isometric muscle strength in left and right side in women and men. So this findings may assist in the measure of whole body muscle strength.

• 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.

• 물리치료
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• s.48
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• pp.3-5
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• 1987

• Physical Therapy Korea
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• v.8 no.3
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• pp.27-34
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• 2001

Physical therapists have been using biofeedback training to induce improvements in various circumstances. The purpose of this study was to compare the effects of visual and tactile feedback using electrical stimulation on quadriceps strength. Nineteen women without known impairment of the neuromusculoskeletal system volunteered for this study. Subjects were randomly allocated into three groups: visual feedback, tactile feedback, and control group. The torque of isometric knee extension force was measured. Subjects were asked to exert the maximal isometric contraction force of quadriceps over a 30 second period. The resting period of 10 minutes was given after the maximal isometric contraction to avoid the muscle fatigue. In between groups comparison, significant differences of the peak torque and the torque area were found on the performance of the maximal isometric contraction of quadriceps (p<.05). The values peak of torque and torque area were significantly higher during visual feedback than tactile feedback. The results of this study suggest that visual feedback is more powerful than tactile feedback (p<.01).

• Journal of Mechanical Science and Technology
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• v.14 no.3
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• pp.338-349
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• 2000

Neck muscle forces and spinal loads at the C4/5 level were estimated that result from isometric voluntary ramp efforts gradually developing to maximums in flexion, extension, left lateral bending and right lateral bending. Electromyographic (EMG) activities, a three-dimensional anatomic data of the neck and a hybrid model, EMG-assisted optimization (EMGAO) model, were used. The model computed the cervical loads at 25%,50%,75%, and 100% of peak moments. The highest model-predicted C4/5 joint compressive forces occurred during flexion; $361\;({\pm}164)\;N,\;811\;({\pm}288)\;N,\;1207\;({\pm}491)\;N\;and\;1674\;({\pm}319)\;N$ in 25%, 50%, 75% and 100% of peak moment respectively. Variations in load distribution among the agonistic muscles and co-contractions of antagonistic muscles were estimated during ramp efforts. Results suggest that higher C4/5 joint loads than previously reported are possible during isometric, voluntary muscle contractions. These higher physiological loads at C4/5 level must be considered possible during orthopedic reconstruction at this level.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.195-203
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• 2006

The isometric rehabilitation program was applied to 47 people of the aged low back patients(man 22 people, woman 25 people) twice a week for 8weeks. The Medx was used to study an effect on a change for extended strength ratio(ESR) according to a posture change. The isometric ESR at each flexion angle ($0^{\circ}$, $12^{\circ}$, $24^{\circ}$, $36^{\circ}$, $48^{\circ}$, $60^{\circ}$, $72^{\circ})$ was measured total 3times("before excercise", "on 4th week after excercise", "8th week after excercise") and analyzed. So, we could come to a conclusion as follows. 1. The maximum extended strength measured at a range of 7 angles for an isometric excercise of 8 weeks increased than "before an excercise", including that men have an increase of 39.51% and women have 62.92% in training effect. All of men and women showed statistically significant increase in physical strength(p<.001).excercise") and analyzed. So, we could come to a conclusion as follows. 2. After an excercise of 8 weeks, man showed 62.17% at zero degree and 49.115% at 12 degree respectively in maximum extended strength. Women showed 106.6% at zero degree and 86.16% at 12 degree. In view of this, respectively man have increase rate of physical strength over 31% and women have over 46% at all angles, also have significant increase in extension angle(p<.001). 3. A change for isometric ESR have a decrease of 27.68% for men and 74.66% for women than before isometric excercise of 8 weeks statistically significantly(p<.05, p<.00l). Men showed 1.77:1 of a similar ratio in the decrease effect comparing with normal people, but women showed 225:1.

• Physical Therapy Korea
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• v.31 no.2
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• pp.114-122
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• 2024

Background: The peroneus longus (PL) and peroneus brevis (PB) function as the primary muscles of eversion, a movement closely associated with tibial external rotation for ankle mortise stability. Ankle motion and tibial rotation vary based on different ankle and knee positions. Objects: This study aimed to investigate the PL, PB, and biceps femoris (BF) muscle activation and eversion strength during side-lying isometric eversion exercise based on different ankle positions (neutral [N] and plantarflexion [PF]) and knee positions (90° flexion [KF] and extension [KE]). Methods: Thirty healthy adults with an Ankle Joint Functional Assessment Tool score of ≥ 22 were recruited (mean age = 24.8 ± 3.1 years). Maximal isometric eversion strength and submaximal muscle activation of the PL, PB and BF were measured during isometric eversion exercise in side-lying. A 2 × 2 repeated measures analysis of variance was performed to investigate differences in muscle activation and strength. Results: The PL and PB muscle activation showed significant main effects with the knee and ankle positions (p < 0.05); activation was greater in the KE and PF positions than in the KF and N positions. The BF muscle activation showed a significant interaction effect with knee and ankle positions, which was greater in knee extension and ankle plantarflexed (KEPF) position than in knee flexion and ankle plantarflexed (KFPF) position (p < 0.05). Eversion strength showed a significant main effect only in ankle position (p < 0.05) and was greater in the N position than in the PF position. Conclusion: The results of this study indicate that the KEPF position can be recommended to facilitate contraction of the PL and PB during side-lying eversion exercise. Furthermore, the effects of the knee-ankle positions should be considered for measuring ankle eversion strength and implementing the isometric submaximal side-lying eversion exercise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.212-220
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• 2020

This study examines the effects on isometric lumbar extension strength, dynamic balance ability, and range of motion, after administering 8 weeks SEBT exercise (dynamic balance exercise) and Lumbar Stabilizing exercise, to open laser lumbar microdiscectomy patients. Totally, 14 patients who underwent preservation treatment for 6 weeks after undergoing open laser lumbar microdiscectomy, were enrolled for the study. Patients were randomly assigned to the Lumbar Stabilizing Exercise Group (LSG, n=7) and SEBT Exercise + Lumbar Stabilizing Exercise Group (SGLS, n=7). Results indicate that isometric lumbar extension strength ratio significantly decreases after 8 weeks rehabilitation exercise in both the LSG (p=0.007) as well as SLSG (p=0.024) groups. Normalized reach distance of the three directions in the Y-balance test to examine the dynamic balance capability showed a significant increase in both groups. The dynamic balance capability showed significant increase to the left (LSG, p=0.010; SLSG, p=0.002) and right (LSG, p=0.002; SLSG, p=0.002). Moreover, significant increase was also obtained in the range of joint operation, in both LSG (p=0.006) and SLSG (p=0.017) groups. These results indicate that both groups of rehabilitation exercise achieve positive outcomes on the isometric lumbar extension strength, range of motion, and dynamic balance ability. However, some results suggest that the SEBT program is likely to have a better efficacy.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.140-147
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• 2021

Objective: The purpose of this study is to identify the mechanism of changes in maximum voluntary torque with the magnitude and duration of pre-activation torque during voluntary isometric knee extension. Method: 11 male subjects (age: 25.91±2.43 yrs., height: 173.12±3.51 cm, weight: 76.45±7.74 kg) participated in this study. The subjects were required to produce maximal voluntary isometric torque with a particular pre-activation torque condition. The properties of pre-activation torque consisted of the combinations of 1) three levels of magnitude, e.g., 32 Nm, 64 Nm, 96 Nm, and 2) two levels of duration, e.g., 1 sec, and 3 sec; thus, a total of six conditions were given to the subjects. The force and EMG data were measured using the force transducers and wireless EMG sensor, respectively. Results: The results showed that the maximum voluntary torque increased the most with relatively large and fast (96 Nm, 1 sec) pre-activation condition. Similarly, with relatively large and fast (96 Nm, 1 sec) preactivation, it was found that the integrated EMG (iEMG) of the agonist muscles increased, while no significant changes in the co-contraction of the antagonist muscles for the knee extension. Also, the effect of pre-activation conditions on the rate of torque development was not statistically significant. Conclusion: The current findings suggest that relatively larger in magnitude and shorter in duration as the properties of pre-activation lead to a larger magnitude of maximal voluntary torque, possibly due to the increased activity of the agonist muscles during knee extension.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.4 s.247
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• pp.457-464
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• 2006

The anterior cruciate ligament (ACL) is liable to a major injury that often results in a functional impairment requiring surgical reconstruction. The success of reconstruction depends on such factors as attachment positions, initial tension of ligament and surgical methods of fixation. The purpose of this study is to find isometric positions of the substitute during flexion/extension. The distance between selected attachments on the femur and tibia was computed from a set of measurements using a 6 degree-of-freedom magnetic sensor system. A three-dimensional knee model was constructed from CT images and was used to simulate length change during knee flexion/extension. This model was scaled for each subject. Twenty seven points on the tibia model and forty two points on the femur model were selected to calculate length change. This study determined the maximum and minimum distances to the tibial attachment during flexion/extension. The results showed that minimum length changes were $1.9{\sim}5.8mm$ (average $3.6{\pm}1.4mm$). The most isometric region was both the posterosuperior and anterior-diagonal areas from the over-the-top. The proposed method can be utilized and applied to an optimal reconstruction of ACL deficient knees.