• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.1
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• pp.47-54
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• 2020

Background: This study examined the changes in the leg muscle activities of 30 healthy subjects according to different pressures caused by isometric hip adduction during squat exercise. Methods: With their knee flexed at 60°, the subjects performed isometric hip adduction with a pressure of 0, 20, 40, and 60mmHg. Surface electromyography was used to measure their muscle activities. Changes in the activities of the muscles, such as the gluteus maximus (GMAX), Gluteus medius (GM), vastus medialis oblique (VMO), vastus lateralis oblique (VLO), biceps femoris (BF), and Tensor fasciae latae (TFL) muscles, were analyzed. Results: The activities of the VMO, VLO, GM, BF, and GMAX muscles were significantly different after exercise compared to that before exercise (p<.05). The activities of all the leg muscles measured were highest at a pressure of 60mmHg during isometric hip joint adduction. Conclusion: The pressure produced by isometric hip joint adduction during squat exercise increased the leg muscle activities of the subjects. These results will provide basic data on effective squat exercise to alleviate knee joint diseases.

• Physical Therapy Korea
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• v.23 no.2
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• pp.75-83
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• 2016

Background: Several studies have discussed diverse exercise methods considered to be useful for the selective contraction of the vastus medialis oblique (VMO) muscle for the treatment of patellofemoral pain syndrome. Some studies have reported that exercise methods, including hip adduction, in closed kinetic chain exercises are more effective in terms of the muscle activation of the VMO and the timing of the muscle's initial contraction. We focused on isometric contraction during a closed kinetic chain exercise with hip adduction. Objects: The purpose of this study was to examine muscle activation in the VMO and the vastus lateralis (VL) and the onset time difference between their initial contractions via closed kinetic chain isometric quadriceps femoris exercises including hip adduction. Methods: In total, 36 healthy subjects adopted two hip positions during isometric contraction of the quadriceps femoris in a closed kinetic chain exercise (hip neutral and hip adduction position). Statistical analyses were conducted using a paired t-test (${\alpha}=.05$). Results: Isometric contraction of the quadriceps femoris in a closed kinetic chain exercise caused a greater increase in VMO muscle activity in the hip adduction position [$52.68{\pm}22.21$ percentage of maximal voluntary isometric contraction (%MVIC)]than the hip neutral position ($43.43{\pm}19.85%MVIC$). The onset time difference (VL-VMO) decreased more in the hip adduction position ($-82.14{\pm}34.2ms$) than the hip neutral position ($73.94{\pm}2.94ms$). Conclusion: We recommend this exercise as a clinically useful therapeutic method for patients with patellofemoral pain syndrome due to weakening of the VMO muscle and lateral inclination of the patella.

• Physical Therapy Korea
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• v.17 no.2
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• pp.1-9
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• 2010

To develop effective training methods for strengthening a weakened quadriceps femoris muscle in hemiplegic patients, we examined the effects of maximal isometric contraction of the nonparalyzed knee joint on the electromyographic activities of the paralytic muscle. An electromyogram (EMG) was used to record the electromyographic activities of the paralytic quadriceps femoris muscle in 27 hemiplegic patients. The maximal isometric contraction was measured for each subject to normalize the electromyographic activities. The maximal isometric extension and flexion exercises were randomly conducted when the knee joint angles of the nonparalyzed knees were $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$. The patients were encouraged to maintain maximal isometric contractions in both knee joints during each measurement, and three measurements were taken. A one-minute rest interval was given between each measurement to minimize the effects of muscle fatigue. An average from the three values was taken as being the root mean square of the EMG and was recorded as being the maximal isometric contraction. The electromyographic activity obtained for each measurement was expressed as a percentage of the reference voluntary contraction, which was determined using the values obtained during the maximal isometric contraction. The results of this study are summarized as follows: First, when the knee joint angle of the nonparalyzed knee was $0^{\circ}$, the electromyographic activities of the paralytic medial aspect of rectus femoris were related to measurement by a maximal isometric flexion exercise than by an extension exercise (p<.05). Second, when the knee joint angle of the nonparalyzed knee was $90^{\circ}$, the electromyographic activities of the paralytic lateral aspect of rectus femoris were related to measurement by a maximal isometric flexion exercise than by an extension exercise (p<.05). The results show that myoelectrical activities of paralytic quardriceps were not related to measurement angles and exercise directions of the nonparalized knee joint. Studies on various indirect intervention to improve muscular strength of patients with nervous system disorders of the weakened muscle should be constantly conducted.

• Physical Therapy Korea
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• v.7 no.3
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• pp.81-89
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• 2000

The purpose of this study was to determine the effect of electrical stimulation biofeedback on motor learning of quadriceps muscle isometric exercise in 3 patients who have undergone total knee replacement surgery. A multiple baseline design across subjects was used. The electrical stimulation biofeedback was provided with each patient during quadriceps isometric exercise, which last 10 to 14 sessions with 10 repetitions each sessions. After training patients received 4 retention tests. Maximum muscle activity was measured pre- and post- electrical stimulation biofeedback training and retention test to evaluate the effect of biofeedback training. Maximum isometric muscle activity of quadriceps was increased after electrical stimulation biofeedback training in all subjects. The results indicate that a electrical stimulation biofeedback training is a useful method to improve motor learning of quadriceps isometric exercise in total knee replacement.

• The Journal of Korean Physical Therapy
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• v.13 no.1
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• pp.73-82
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• 2001

In order to study the effect of the isometric exercises on the flexibility. the strength and the waist and hip circumferences, 10 female university students who aged 22.10 ${\pm}$ 1.10 years were measured by sit-up for strength, and trunk flexion test and trunk lifting for flexibility, and also measured by waist and hip circumferences before and during, and after the Swiss ball exercise program. Statistical analysis was performed using SPSS/PC WIN 7.0 version. and one-way repeated ANOVA Test, The results of the test were as shown; We found that the number of performing sit-up was increased. and the trunk flexion test and trunk lifting was increased, and the waist and hip circumferences were increased after the 6 weeks Swiss ball exercise program. These findings indicate that Isometric exercise using Swiss ball could be beneficial to the low back pain patients due to the effect of increasing strength and flexibility of the patients.

• Korean Journal of Exercise Nutrition
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• v.17 no.2
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• pp.25-34
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• 2013

This study was conducted to investigate the relationship between ACE gene polymorphism and muscle damage parameters after eccentric exercise. 80 collegiate males were instructed to take an eccentric exercise with the elbow flexor muscle through the modified preacher curl machine for 2 sets of 25 cycles (total 50 cycles). The maximal isometric strength, muscle soreness, creatine kinase (CK), and myoglobin (Mb) were measured before exercise, and 0, 24, 48, 72, and 96 hrs after exercise. The result showed that after the eccentric exercise, the maximal isometric strength significantly decreased by more than 50% (p < 0.001) and the muscle soreness, CK, and Mb significantly increased compared to those before the exercise (p < 0.001). The ACE gene polymorphism of the subjects was classified using real-time polymerase chain reaction (real-time PCR). The result showed that it consisted of 38 cases of type II (46.4%), 33 cases of type ID (43.4%), and 9 cases of type DD (10.2%). The Hardy-Weinberg equilibrium for ACE gene polymorphism was shown to have p = 0.653, which showed that each allele was evenly distributed. Although significant differences in the changes in the maximal isometric strength, muscle soreness, CK, and Mb were found according to time course (p < 0.001), no significant differences in the changes in the maximal isometric strength, muscle soreness, CK, and Mb were found according to ACE gene polymorphism. Furthermore, no significant difference in the changes in the muscle damage parameters was found according to interaction between ACE gene polymorphism and time course (p > 0.05). In conclusion, the level of the muscle damage parameters changed in the injured muscle after eccentric exercise, but these changes in the muscle damage parameters were not affected by ACE gene polymorphism. The result of this study indicates that ACE gene is not a candidate gene that explains muscle damage.

• Journal of Korean Physical Therapy Science
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• v.2 no.3
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• pp.587-598
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• 1995

The purpose of this study was to test the microcurrent electrical neuromuscular stimulation on muscle soreness, serum creatine kinase levels and force deficits evident following a high-intensity eccentric exercise bout. 10 volunteer male subjects were randomly assigned to a treatment group or to a control group. Exercise consisted of high-intensity eccentric contractions of the elbow flexors. Resistance was reduced as subjects fatigued, until they reached exhaustion. Muscle soreness rating was determined using a visual analog scale. Serum creatine kinase levels were analyzed using a blood sample. Force deficits were determined by measures of maximal voluntary isometric contraction at $90^{\circ}$ of elbow flexion on a Orthotron II dynamometer. Muscle soreness rating, serum creatine kinase levels and maximal voluntary isometric contraction were determined at the before exercise and again at 24 and 48 hours postexericse. Treatments were applied immediately following exercise. The control group subjects rested following their exercise bout. Statistical analysis showed significant increases in muscle soreness rating and significant decreases in maximal voluntary isometric contraction when the before exercise was compared with 24 and 48 hour measures(p<0.01). No significant effects were observed between groups in muscle soreness rating and maximal voluntary isometric contraction(p>0.05). Highly significants differences in serum creatine kinase levels were found using on Analysis of variance(ANOVA) repeated measures between groups for each time cycles(p<0.001). This modality may have benefits when used early stage in the muscle damage.

• The Journal of Korean Physical Therapy
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• v.22 no.5
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• pp.9-16
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• 2010

Purpose: The purpose of this study was to compare modified sling exercise and general isometric exercise in patients with shoulder impingement syndrome. Methods: Twenty subjects were studied. The control group, n1 = 10, received instructions for doing general isometric (ISO) exercise. An experimental group, n2 = 10, received instructions for doing push-ups from standing and sitting positions and modified scapular exercises using a sling (3 sets, 3 times per week for 6 weeks). To evaluate the effects of exercise, subjects were evaluated using a visual analog scale for pain, a goniometer for range of motion, and electromyography for onset time of muscle contraction. Statistical analysis was done using the Wilcoxon Signed rank and Mann-Whitney U tests. Results: Pain in the sling group was significantly decreased after 6 weeks of treatment (p<0.05) pain in the general ISO exercise group was not significantly decreased (p>0.05). Flexion and external rotation were significantly increased after 6 weeks of treatment in both groups (p<0.05) and the change in the Sling group was greater than in the ISO group (p<0.05) in the flexion test. Time of onset of contractions in the Sling group for the upper trapezius, lower trapezius and serratus muscle were significantly decreased after 6 weeks of treatment (p<0.05), but the onset time for the middle trapezius did not significantly decrease (p>0.05). Conclusion: Scapular stabilizing exercise using a sling increases range of motion and decreases pain, and onset time of muscle contraction in patients with impingement syndrome.

• 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.

• The Journal of Korean Physical Therapy
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• v.13 no.3
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• pp.585-596
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• 2001

The twenty one individuals with total knee replacement who were admitted to Kang-Dong Hospital for comprehensive physical therapy were studied in order to demonstrate the effectiveness of an isokinetic test program using the Cybex 6000 machine. The subjects were divided into three groups with the isometric exercise group receiving isometric exercise, the isokinetic eccentric exercise group, and isokinetic concentric exercise group receivind isokinetic exercise(eccentric, concentric) to knee flexors and extensors muscles for a six weeks' period using the Cybex 6000. The results are follow: 1. The extensors were increased significantly at all groups after 6 weeks training(p<.05). The flexors were increased significantly at isokinetic eccentric and isokinetic concentric group but no significantly differences at isometric group(p>.05) 2. At the effect of extensors and flexors after 6 weeks training. higher to 30$^{\circ}$ /sec of isokinetic concentric exercise, lower to 120$^{\circ}$ /sec of isometric exercise. 3. The peak torque was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups. 4. The total work was more increased significantly in the flexors and extensors of the isokinetic conccentric exercise among three groups. 5. The ratio of peak torque to body weight were more increased significantly in the flexors and extensors of the isikinetic conccentric exercise among three groups. 6. The average power was more increased significantly in the flexors and extensors of the isikinetic conccentric exercise among three groups. 7. The average R.O.M in the pre-exercise and post-exercise was not different significantly in all three groups. According to the above results, In the muscle strength recovery for total knee replacement patients, isokinetic concentric exercise group was significantly greater than the isokinetic eccentric and isometric exercise groups after a six weeks training.