• PNF and Movement
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• v.11 no.2
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• pp.111-117
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• 2013

Purpose : The purpose of this study was to examine the activity of the knee flexor and extensor with ankle plantar flexion and dorsiflexion. Methods : A total of 18 subjects(Male 6, female 12) performed 4 lower extremity patterns of PNF and the activities of the vastus medialis oblique, rectus femoris, vastus lateralis, biceps femoris, semitendinosus ipsilateral sides were measured using electromyography. Results : During 4 lower extremity patterns of PNF, knee flexor and extensor muscle activity were significantly difference. Knee extensors were shown to be higher knee extension and ankle dorsiflexion combined pattern. Knee flexors were shown to be higher knee flexion and ankle plantarflexion combined pattern. Conclusion : We suggest that it is efficient to strengthening of knee extensors with ankle dorsiflexion and to strengthening of knee flexors with ankle plantar flexion. Also, for the functioning as toe standing, we have to choice appropriate movement pattern.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.697-709
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• 2000

The purpose of this study was to evaluate the effectiveness of ElectroMyoscope(Electro_Acuscope and Myopulse) in tissue repairing on fatigue quadriceps femoris(rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis). Subjects were female adult volunteers with (n=13) and without (n=5) chronic fatigue muscle pain. We needed to fatigue the rectus femoris by overusing of a Cybex machine exercise. We turned the Electro-Myoscope to treatment mode and treated with treatment probe on the fatigue muscle, then turned instrument back to EMG and took the reading. The results indicated that the reading after the treatment was lower than before the treatment. A two-tailed t-test and Chi square indicated significant results(P<.03). It appears that the Electro-Myoscope is effective in treatment on the fatigue muscle.

• International Journal of Contents
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• v.6 no.1
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• pp.41-46
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• 2010

The aim of this study was to investigate the effect of different shoe-heel heights on the surface electromyographic (EMG) activity of vastus medialis (VM) and vastus lateralis (VL) during treadmill walking in female patients with patellofemoral pain (PFP). Nineteen women with PFP participated in this research. EMG signals were recorded from the VM and VL of both sides and were compared during the treadmill walking. The subjects walked on a treadmill wearing shoes of three different heel heights: 1 cm, 3 cm and 7 cm. Each subject walked on a treadmill for five minutes at a speed of 2 km/hour with three minutes resting intervals between consecutive trials. The data were analyzed by one-way repeated-measures analysis of variance. The results of the present study indicate that EMG data of the VM and VL of female patients with PFP did improve with an increase in the height of the shoe heel, which were statistically significant. Additionally, the EMG activity of VM increased more dramatically than that of VL associated with the task of walking with high-heeled shoes on the treadmill. This study suggests that the type of high-heeled shoes is related to the VM and VL muscle activation patterns contributing to knee joint pathologies in female patients with PFP.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.2
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• pp.135-143
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• 2011

Purpose: The purpose of this study was to investigate onset timing of vastus medialis oblique(VMO) relative to vastus lateralis(VL) the VMO/VL electromyographic(EMG) ratio according to heel height Methods: A repeated measures design was used. Fifteen healthy female college students with no known knee musculoskeletal dysfunction were recruited this study. They carried out a standardised stair acent activity under 4 conditions; barefoot, and with heel height of 1, 3, 7 cm. Muscle activity was measured by surface EMG (Myosystem 1400A, Noraxon Inc., U.S.A). Data were analysed using $1{\times}4$ repeated measures ANOVA. Results: Onset timing differed with heel height(p<.05). However, the VMO/VL EMG ratio was not significantly difference between conditions. Conclusion: We found that 7 cm heel height delayed in VMO onset compared with 3 cm heel height during stair ascent, but no change in the relative EMG intensity of VMO and VL as measured by th VMO/VL ratio. The findings indicate that high-heeled shoes may have disadvantages in knee stability because of delayed onset of VMO. Due to a lack of knee joint stability, wearing of high heeled shoes should be avoided.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.981-982
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• 2013

• Physical Therapy Korea
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• v.15 no.2
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• pp.54-63
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• 2008

The purpose of this study was to examine the effect of the hip internal rotation on knee extensor and hip abductor electromyographic (EMG) activity during stair up and stair down mobility. Eighteen healthy subjects were recruited. All subjects performed stair up and down movements on a step of 30cm height while maintaining the hip in neutral (condition 1) and hip in internal rotation (condition 2). Surface EMG activity was recorded from five muscles (gluteus maximus, vastus lateralis (VL), vastus medialis oblique (VMO), posterior gluteus medius (Gmed), and tensor fascia latae (TFU)) and hip internal rotation angle was measured using a three dimensional motion analysis system The time period for stair up and down was normalized using the MatLab 6.5 program, and EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). The EMG activities according to the hip rotation (neutral or internal rotation) during the entire time period of stair up and down in each phase were compared using a paired t-test. During the entire period of stair up, the EMG activities of VL and TFL in condition 2 were significantly greater than in condition 1 (p<.05). During the entire period of stair down, the EMG activities of VL and TFL in condition 2 were significantly greater than in condition 1 (p<.05). However, the EMG activities of the other muscles were not significantly different between the conditions (p>.05). These results suggest that the stair up and down maintaining hip internal rotation was could be a contributing factor on patellar lateral tracking.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.18 no.2
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• pp.41-47
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• 2012

Background: This study was designed to investigate the correlation between electromyography (EMG) activities in the vastus medialis oblique (VMO) vs vastus lateralis (VL) activity ratio and the valgus collapse knee position while stepping down. Methods: Twenty healthy women volunteered to participate in this study. We measured the frontal-plane projections of the knee valgus angle, knee valgus distance, and hip adduction angle by using a digital camcorder. After 3 repetitions of the step down (dominant side) exercise, the findings of the static and dynamic phases were analyzed. EMG activities data of the VMO:VL activity ratio were recorded during the step down exercise and were normalized to the maximal voluntary isometric contraction (MVIC) of the quadriceps. A paired t-test was used to compare the findings of the static and dynamic phases. We analyzed the Spearman's rank order correlation coefficient between the and VMO:VL ratio. Results: Hip adduction angle, knee valgus angle, VMO activity, VL activity, VMO:VL activity ratio were statistically higher in the dynamic phase than in the static phase (p<.05). Frontal-plane projections of knee valgus angle were significantly correlated with hip adduction angle (r=.459, p<.05) and knee valgus distance (r=.505, p<.05). However, the EMG activity ratio of the VMO and the VL did not show a significant change during step down exercise with respect to hip adduction angle (p=.875), knee valgus angle (p=.618), and knee valgus distance (p=.701). Conclusion: The results from this study indicate that frontal-plane projections of knee valgus angle were associated with hip adduction angle and knee valgus distance. On the basis of these results, the knee valgus distance may be used to determine the valgus collapse knee position while stepping down.

• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.43-52
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• 2016

The purpose of this study was to suggest the effective squat exercise position to strengthening vastus medialis oblique, and vastus lateralis in quadriceps. Subjects were twenty patients with patellofemoral pain syndrome (PFPS) volunteered to participate in this study. All subjects were applied to static squat convergence exercise with knee flexed $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ for 30 seconds total 5 times. Measurement variables were maximal voluntary isometric contraction (MVIC) of the quadriceps, Q angle and length of thigh. Those were measured before and after the squat exercise on knee joint angle, change rate of which were used for statistical analysis. As a result, squat exercise with knee flexed $90^{\circ}$ increase significantly among knee joint angle in the MVIC change rates of quadriceps (p<.05), however the rates of Q-angle and length change of thigh showed no significant difference. Therefore, this findings suggest that squat exercise with knee flexed $90^{\circ}$ strengthen quadriceps effectively in patients with PFPS.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.319-327
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• 2019

The muscle activity and balance ability of the acute stroke patient has been checked by the functional electrical stimulation using biofeedback fusion postural control training in this study. Functional electrical stimulation using biofeedback fusion postural control training have been implemented on 15 trainees and general biofeedback fusion postural control training have been implemented on another 15 trainees for 30 minutes at 5 times per week during 8 weeks, and vastus lateralis, vastus medialis, rectus femoris and biceps femoris have been measured using the biceps femoris to evaluate the muscle activity of the lower extremity. The moving surface area, whole path length and limited of stability have been measured using biorecue to measure the balance ability. There was statistically meaningful difference on the vastus lateralis, vastus medialis, rectus femoris and biceps femoris in the muscle activity of the lower extremity and there was statistically meaningful difference on surface area, whole path length and limited of stability in the balancing ability. Based on above, it is realized that the functional electrical stimulation using biofeedback fusion postural control training is more effective than the general biofeedback fusion postural control training on the improvement of the muscle activity of the lower extremity and the balance ability.

• Journal of Digital Convergence
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• v.11 no.8
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• pp.265-272
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• 2013

The purpose of this study was to provide a foundation for the methods of stretching in sports activities. The subjects were normal adults, the applied exercise was dynamic and static stretching and the research methods were measuring the jump height and muscle activity during jumping with subsequent data comparison and analysis. Twenty normal adults were randomly divided into 2 groups, and each group performed dynamic or static stretching. Jump height and the vastus lateralis and gastrocnemius muscle activities were measured during jumping, which was performed immediately before and after stretching. Statistical analysis was performed using an analysis of covariance. The results indicated that dynamic stretching was more effective than static stretching with respect to both jump height (p<.05) and muscle activity of the vastus lateralis (p<.05). Consequently, it was believed that dynamic stretching should be applied as a warm-up exercise for athletes who need to build and maintain high muscle strength.