• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.33.1-33.1
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• 2008

• Korean Journal of Applied Biomechanics
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• v.33 no.1
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• pp.10-16
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• 2023

Objective: The purpose of this was to find out the muscle activity of the quadriceps femoris by gender when sitting on a chair while performing stairs gait (US; Up-stairs, DS; Down-stairs). Method: 13 male subjects (age: 22.00 ± 1.68 yrs, height: 174.85 ± 6.10 cm, weight: 68.15 ± 9.83 kg) and 15 female subjects (age: 21.17 ± 1.58 yrs, height: 168.20 ± 5.55 cm, weight: 55.73 ± 6.94 kg) participated in this study. The study used wireless three channel EMG. Results: In this study, there was no gender difference in quadriceps femoris activity during the US and DS periods, and there was no significant difference between the male group before and after postural maintenance during the US and DS periods. The quadriceps muscle of the female group also did not show a significant difference before and after US sitting. However, the vastus medialis muscle activity during DS in the female group was significantly lower after application than before application of maintaining a sitting posture (p<.05). There was no interaction effect between the 15-minute sitting position application and gender. Conclusion: Our results demonstrate that sitting in a chair affects the transient functioning of the quadriceps muscle in women. Therefore, emphasize the need for active rest when sitting in a chair for long periods of time.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.3
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• pp.375-383
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• 2010

Purpose : The purpose of this study was to investigate a modified maneuver for quadriceps setting exercise for patients with knee osteoarthritis. Methods : The patients were randomly divided into a modified maneuver for quadriceps setting exercise group(MQG) and conventional quadriceps setting exercise group(CQG). Total of 28 patients received a modality with training for 1 hour, three times a week for 12 weeks. Results : Each group showed significant reductions in the WOMAC(Western Ontario McMaster Universities Osteoarthritis) Index, mobility, and muscle strength after 12 weeks. In pain, physical function, and hamstring muscle strength, there was a statistically significant difference between groups. Conclusion : According to the results, MQG experienced less pain, physical function, and increased more hamstring muscle strength than NQG.

• The Journal of Korean Physical Therapy
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• v.28 no.3
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• pp.212-216
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• 2016

Purpose: The current study seeks to identify the relationship between torque values of the quadriceps and muscle activity during isometric and isokinetic exercises. Methods: The subjects of the study included 29 healthy individuals 17 men and 12 women) who took part in isometric and isokinetic exercises that utilized the quadriceps. The isometric exercises were performed three times each at 4 different angles (0, 30, 60, and 90 degrees). For the isokinetic exercises, concentric contraction and eccentric contraction were undertaken three times each at two angular velocities (30 and 60 degrees). Results: The muscle activity of the quadriceps during the isometric exercises showed significant differences at the 30, 60, and 90 degree angles. During the concentric contractions and eccentric contractions, muscle activity at the peak torque of the quadriceps indicated significant differences in vastus medialis, vastus lateralis, and rectus femoris at angular velocities of 30 and 60 degrees. Conclusion: When applied clinically based on the biomechanical analysis of the current study, it is possible to anticipate and selectively strengthen muscles with isometric and isokinetic exercises for not only healthy adults and professional athletes, but also for those who experience limited knee movement for long periods following knee surgeries.

• Physical Therapy Korea
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• v.13 no.4
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• pp.10-15
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• 2006

This study examined the ability of human subjects to match a force in their quadriceps muscle during fatigue. Twenty subjects (mean age: 23.4 yrs, mean height: 167.8 cm, mean weight, 62.6 kg) were enrolled in the experiment. In the force-matching task, the quadriceps muscle generated 50% of the MVIC (maximum voluntary isometric contraction) torque under visual control and then without visual feedback. After inducing fatigue in the quadriceps muscle, the subjects were required to match 50% of the MVIC torque without visual feedback. The perceived magnitude of the force and force-matching errors were measured. 50% of the MVIC torque was perceived from 39.96 Nm in the pre-fatigue condition to 44.95 Nm in the post-fatigue condition. 50% of the MVIC torque-matching errors increased significantly from .55% in the pre-fatigue condition to 9.6% in the post-fatigue condition (p<.001). in addition, there were significantly more force-matching errors in women than in men (p<.01). In conclusion muscle fatigue can interfere with a subject's ability to match a force. This suggests that muscle fatigue may contributes to the sensitization of the proprioception.

• Journal of The Korean Society of Integrative Medicine
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• v.2 no.1
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• pp.15-21
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• 2014

Purpose : The aim of this study was to find out differences between muscle activity of quadriceps according to hip angle. Method : 40 healthy adults produced maximum isometric muscle contraction of quadriceps femoris and each part of the quadriceps femoris were measured with a surface EMG in hip joint angle of $90^{\circ}$, $135^{\circ}$, $180^{\circ}$. Result : There was no significant difference between muscle activity of vastus medialis and lateralis according to hip angle. But there was significant difference in muscle activity of rectus femoris and the muscle activity was maximum at 135 degrees of hip angle. Conclusion : In conclusion, maximum muscle activation of rectus femoris is affected by hip angle, and the findings from this study may be helpful for physical therapists in selecting hip position when instructing patients to do Q-setting exercise. So, we suggest that patients perform Q-setting exercise at 135 degrees of hip angle for the best result.

• 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.18 no.6
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• pp.59-65
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• 2006

Purpose: This study was to investigate the effects of rehabilitation exercise program on the muscle strength and pain in elderly with knee osetoarthritis. The progressive rehabilitation program included flexibility, strength, endurance, and active range of motion exercise and functional activities. Methods: Nineteen subjects with osteoarthritis of the knees randomized to exercise group(n=10) or control group(n=9), but fourteen subjects completed the trial with an adherence of 70% to the intervention and 77% to the control. The knee pain with VAS and quadriceps strength were evaluated at pre- and post-intervention. Results: The data were analysed with the two-way repeated ANOVA and paired t-test. The pain and quadriceps muscle strength had no difference among the groups and times. Within experimental group, pain was significantly decrease and quadriceps muscle strength significantly increased between pre and post intervention, while the control group showed no changes. Conclusion: Rehabilitation exercise program for knee osteoarthirits appear to be effective in knee pain and quadriceps muscle strength.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.2
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• pp.49-57
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• 2023

Background: This study aims to investigate the effect of lower limb strengthening training combined with electro muscle stimulation on the quadriceps femoris muscle activity of soccer players. Methods: Thirty university soccer players were selected as study subjects and divided into a lower limb strengthening training group combined with EMS (Group I) and a general lower limb strengthening training group (Group II), and 15 subjects were randomly assigned. After receiving general soccer training, subjects in this study additionally mediated lower limb strengthening training combined with EMS and general lower limb strengthening training for 26 minutes, 3 times a week for 8 weeks. Quadriceps femoris muscle activity was analyzed before mediation. Vastus medialis, vastus lateralis, and rectus femoris were measured with maximum isometric contraction in the manual muscle test position in order to analyze leg muscle activity. The same items as above were re-measured and a between-group analysis was conducted after 8 weeks of mediation. Results: As a result of comparative analysis of lower extremity muscle activity between groups, the lower limb strengthening training group combined with EMS showed a statistically significant difference in lower extremity muscle activity compared to the general lower limb strengthening training group. Conclusion: As a result, it was found that lower limb strengthening training combined with EMS was more effective in improving quadriceps femoris muscle activity. Based on this study, we are going to provide basic data on the possibility of using EMS in the field of sports rehabilitation for soccer players.

• PNF and Movement
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• v.17 no.2
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• pp.311-319
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• 2019

Purpose: This study was conducted to determine the structural change in knees caused by quadriceps angle and the muscle activity in lower limbs. Indirect intervention was provided by using taping for stability in the ankle joints, which affected patellofemoral pain. Methods: The subjects in this study were 20 patients with patellofemoral pain who visited ${\bigcirc}{\bigcirc}{\bigcirc} $ Hospital in Busan. The visual analogue scale measured the dynamic quadriceps angle and the degree of pain felt by the patients while walking down stairs, which was a known factor of patellofemoral pain. In addition, muscle activities in the rectus femoris, vastus lateralis, vastus medialis, tibialis anterior, peroneus longus, and biceps femoris, which affect the knees and ankles, were measured using surface electromyography. The muscle activities were converted into %RVC for this study. The data obtained in this study were analyzed with the Wilcoxon signed-rank test using the SPSS Ver. 25.0 statistical program. The significance level ${\alpha}$ was 0.05. Results: The study results showed that the pain and dynamic quadriceps angle were significantly reduced statistically when applying the calcaneus fixation taping (p<0.05). Muscle activity in the lower limbs was significantly decreased in the vastus medialis, vastus lateralis, and tibialis anterior (p<0.05). Conclusion: The summary of the study results verified that the calcaneus fixation taping reduced the pain and dynamic quadriceps angle by providing stability in the ankle joints. It also produced efficient movement due to the difference in lower-limb muscle activity.