• The Journal of Korean Physical Therapy
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• v.32 no.5
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• pp.302-306
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• 2020

Purpose: The purpose of this study was to investigate comparisons of vastus medialis (VMO) and vastus lateralis (VL) muscle activities according to different heights during drop landing in flatfooted adults. Methods: Fifteen subjects with a flat foot arch and 15 subjects with a normal feet arch were participated. Subjects performed a double limb drop landing task from 20, 40, and 60 cm heights. Surface electromyography was used to measure the muscle activities of the VMO and VL during drop landing. Results: There were significant differences of muscle activities in the VMO, VL, and the VMO and VL ratio between groups. The electromyography values of VMO, VL, and the VMO and VL ratio in the normal group were significantly greater than in the flat foot group, and muscle activities and the VMO and VL ratio significantly increased with landing heights in the both groups. Conclusion: Our results indicated that muscle activity patterns of VOM and VL in the flat foot group were lower at heights than in the normal group, so calf tightness was negative effects on balance and gait ability, so assessment of muscle activation patterns in the knee extensors should be considered during exercise and treatment of flat feet.

• PNF and Movement
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• v.12 no.3
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• pp.167-171
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• 2014

Purpose: The purpose of this study was to show the effects of voluntary change of weight bearing on the vastus medialis oblique and the vastus lateralis ratio during squat exercise. Methods: Twenty-four healthy adults were recruited for this study. The subjects performed squat exercise with median weight bearing, lateral weight bearing and non-changed weight bearing. The muscle activities of the vastus medialis oblique and the vastus lateralis were measured during the squat for all three conditions. The measured data were analyzed using one-way ANOVA to investigate the effect of muscle activation on the each condition. The statistical analyses were performed using SPSS ver. 17.0, and a p-value of less than 0.05 was considered significant for all cases. A post-hoc test was performed using Tukey's test. Results: The study showed that the vastus medialis oblique and the vastus lateralis ratio significantly changed according to the voluntary change of weight bearing during a squat. The vastus medialis oblique and the vastus lateralis ratio significantly decreased under the condition of voluntary lateral weight bearing. Conclusion: We suggest squat exercise on median weight bearing to increase the vastus medialis oblique and the vastus lateralis ratio. If your patient has.

• Physical Therapy Korea
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• v.4 no.1
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• pp.1-10
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• 1997

The purposes of this study were to compare the electromyographic activities from the rectus femoris, vastus medialis oblique portion, vastus medialis longitudinal portion, and vastus lateralis during straight leg raising (SLR) and quadriceps setting (QS) exercise and to determine which exercise is more effective to selectively strengthen the vastus medialis. Thirty two healthy subjects <19 men, 13 women) participated in the study. All participants performed SLR and QS exercises while electromyographic activity was recorded from EMG surface electrodes. Statistical analysis demonstrated significantly greater values for the vastus medialis oblique portion, vastus medialis longitudinal portion, and vastus lateralis activities during QS exercise than for those during SLR exercise. However, the rectus femoris muscle activity between SLR and QS exercises was not significantly different. The ratios of vastus lateralis to vastus medialis during SLR and QS exercise were not significantly different. These results show that QS exercise is more effective for strengthening the quadriceps muscle on the whole than the SLR exercise. As for selective methods of strengthening vastus medialis specifically, both SLR and QS exercises are useful.

• Journal of the Korean Institute of Navigation
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• v.20 no.4
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• pp.81-98
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• 1996

The purpose of this study was analysis of the muscle action in physical exercise in the rolling machine. The rolling machine moved by eletric power-driven was made to keep the constant cycle and size of rolling. The subjects of this study consist of 4 seaman(SM) and 4 landman (LM). The experiment analyzed the muscle power of lower and upper limbs by Intergrated Electromyogram(IEMG). The measurement was made on the ground, and 6 and 8 degrees of rolling separately. This study concludes as follows ; including analysis of IEMG of heavy exercise in two hands curl, a standstill walking and just standing. 1. IEMG of the lower limbs when standing. 1) In 6 degrees of rolling, for the landman(LM), vastus medialis m.(9.73), vastus lateralis m.(9.55), and rectus femores m.(8.73) acted more. As for the seaman(SM), tibialis anterior m.(5.38), biceps femores m.(5.05), and gastrocnemius m.(4.47) acted more. 2) In 8 degrees of rolling, in common, for both LM and SM, it were vastus medialis m.(11.20 and 8.97), vastus lateralis m.(16.20 and 4.63), and tibialis anterior m.(5.13 and 4.47). 3) It was showed that IEMG of LM was larger than that of SM. 2. IEMG of the lower limbs when walking. 1) On the ground, for the LM, gastrocnemius m.(7.08), vastus medialis m.(6.65), and vastus latralis m.(6.60) acted more. As for the SM, vastus lateralis m.(7.08), vastus medialis m.(6.58) and restus femores m.(5.10) acted more. 2) In both 8 and 6 degrees of rolling, vastus medials m.(14.50 and 11.98), vastus lateralis m.(10.10 and 14.10), and gastrocnemius m.(11.75 and 7.10) acted more in two groups. 3) It was showed that IEMG of LM was larger than that of SM. 3. IEMG of the lower limbs when heavy exercise(two hands curl). 1) On the ground, for the LM, vastus lateralis m.(21.68), vastus medialis m.(16.08), and rectus femores m.(14.08) acted more. As for the SM, tibialis anterior m.(16.08), vastus medialis m.(14.58), and vastus lateralis m.(8.78) acted more. 2) In 8 and 6 dgrees of rolling, it were vastus medialis m.(17.05 and 12.45), vastus lateralis m.(37.98 and 17.08), and tibialis anterior m.(19.83 and 13.20). 3) It was showed that IEMG of LM was larger than that of SM. 4. IEMG of the upper limbs when heavy exercise. 1) On the ground, the brachialis m.(44.30 and 17.80), and biceps brachii m.(13.40 and 25.10) acted more in two groups. 2) In both 6 and 8 degrees of rolling, the brachialis m.(37.60 and 24.35), and biceps brachii m.(11.38 and 7.97) acted more in two groups. 3) It was showed that IEMG of SM was larger than that of LM.

• The Journal of Korean Physical Therapy
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• v.32 no.1
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• pp.52-57
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• 2020

Purpose: This study compared the muscle activities of the Vastus medialis oblique (VMO) and the Vastus lateralis (VL) at three different knee extension angles: 90°, 135°, and 180° in the sitting position. Methods: Twenty subjects between 20 and 30 years of age participated in the study. A mobile phone application called the Clinometer was used to measure the knee joint angle. Electromyography (EMG) was performed to measure the muscle activities of the VMO and VL muscles during knee isometric extension exercises. The pulling sensor was used to maintain 70% of the maximum strength of the knee extensor continuously in the sitting position. After attaching the EMG sensor, the subjects were asked to perform isometric knee extension exercises randomly among three knee extension angles (90°, 135°, or 180°) in the sitting position. One-way repeated measures analysis of the variance and a Bonferroni post hoc test was used to identify the VMO and VL muscle activity during knee extension angles among 90°, 135°, and 180°. Results: The VMO and VL muscle activities increased with increasing knee extension angle in the sitting position (p<0.01). Conclusions: Knee extension exercise at a 180° angle in the sitting position can be recommended to increase the muscle activity of the VMO and VL muscle activities efficiently.

• PNF and Movement
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• v.10 no.3
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• pp.25-31
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• 2012

Purpose : This study was intended to compare muscle activity in relation to knee joint angles on closed kinetic chain. Methods : A total of 13 subjects consisting of 5 adult males and 8 adult females were made to make movements maintaining knee joint angles at $30^{\circ}$, $45^{\circ}$ and $90^{\circ}$ on closed kinetic chain and the muscle activity occurring in their vastus medialis, rectus femoris and vastus lateralis was measured. Statistical data were analyzed using oneway ANOVA. Results : On closed kinetic chain, the muscle activity of the vastus medialis, rectus femoris and vastus lateralis increased the most at $90^{\circ}$ among the knee joint angles with statistically significant differences(p<0.05). Conclusion : On closed kinetic chain, it could be seen that as the angle of the knee joint increased, the muscle activity increased.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.3
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• pp.91-98
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• 2023

Purpose : The purpose of this study was to investigate the effect of the posture holding band on muscle activity of the rectus femoris, medial vastus, and vastus lateralis muscles and weight distribution during squat exercise. Methods : This study was conducted with 30 healthy adult men and women in their 20s, and all subjects were randomly assigned to the experimental group and the control group. Squat exercise was performed for 6 weeks. The experimental group received squat exercise while wearing a posture holding band, and the control group applied without wearing a posture holding band. Muscle activity of the quadriceps femoris (rectus femoris, vastus medialis, and vastus lateralis) and weight distribution (knee flexion 0 °, 30 °, 60 °, and 90 °) was measured. Results : According to the results of this study, all three muscles showed a main effect on time and group, and a significant interaction was shown only in the vastus lateralis. In addition, the value of the weight distribution difference according to the knee flexion angle did not show a main effect according to time and group at 30 ° of knee flexion, but showed an interaction. Conclusion : It was confirmed that the application of the posture holding band during squat exercise increased the muscle activity of the quadriceps muscle, and showed greater changes in the vastus lateralis muscle. In addition, it was confirmed that the difference in weight distribution was reduced in the knee flexion, and in particular, a greater change was shown in reducing the difference in weight distribution in the knee flexion of 30 °. Therefore, it is considered that the effect of the exercise can be further enhanced if the unnecessary movement of the trunk is controlled by using equipment such as a posture holding band during squat exercise.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.467-477
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• 2011

This study was performed to investigate the effects of tibial rotation while going up stair on muscle activity of vastus medialis oblique and vastus lateralis, and on patellar displacement. The subjects included 30 people (male: 15; female: 15) who were randomly assigned to the tibial internal-rotation, neutral-rotation, and external-rotation groups. The subjects went up the stair while performing the assigned rotations, and the rotation of the hip and the displacement of the patella were measured using a 3D motion analyzer. In addition, the maximum voluntary isometric contraction (MVIC) of the vastus medialis oblique and vastus lateralis were measured using surface electromyogram. On the tibial internal rotation, the hip rotation significantly appeared in the same direction and so did on the tibial neutral and external rotations(p<.001). Although the MVIC of the vastus medialis oblique and vastus lateralis did not significantly differ by tibial rotation during the stair ascent, the MVIC of the vastus medialis oblique was higher than that of the vastus lateralis during the internal and neutral rotations (p<.05). In addition, during the stair ascent, the displacement of the patella was more significant during the tibial external rotation than during the tibial internal and neutral rotations(p<.001). Thus, patients with patellofemoral pain are required to be considered the effects of tibial rotation for their rehabilitation.

• Journal of muscle and joint health
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• v.17 no.2
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• pp.142-150
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• 2010

Purpose: The purpose of this study was to examine EMG activities and VMO/VL ratio of the vastus medialis oblique, vastus lateralis, and rectus femoris during squat exercise (knee angle: 15, 45, and 60 degrees; tibial rotation: internal rotation, neutral, and external rotation). Methods: Twelve subjects performed squat exercise at each knee angle and tibial rotation while electromyographic (EMG) activity was collected. Statistical analysis consisted of two-way repeated measures analysis of variance with post hoc analysis. Results: There were significant main effects of knee angles and foot positions and interaction effect on EMG activities of vastus medialis oblique and vastus lateralis. VMO/VL ratios were significantly different by tibial rotations and there was an interaction effect. A neutral position produced significantly more VMO/VL activity ratio than that from internally rotated position and externally rotated position at 60 degrees. Conclusion: Considering the interaction effects for EMG activity across quadriceps muscles tested, the 60 degrees knee angle with a neutral foot position may provide the most effective condition for patients with acute patellofemoral syndrome.

• Physical Therapy Korea
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• v.23 no.4
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• pp.9-15
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• 2016

Background: Squatting is one of the best functional exercises to strengthen the quadriceps muscle in independent gait and activities of daily living. Although the use of a gym ball during squat exercise is the most common way of strengthening the vastus medialis oblique (VMO) muscle, published data on this subject are limited. Objects: The purpose of this study was to compare the sequential muscle activation of the VMO and vastus lateralis (VL) muscles during squat exercise using a gym ball at different knee flexion angles. Methods: Forty healthy adults were randomly divided into experimental (squat exercise using a gym ball) and control (squat exercise alone) groups, in which squats were performed at $45^{\circ}$ and $90^{\circ}$ knee flexion. Electromyographic (EMG) activity data were collected over 10 seconds under the 2 angles of knee flexion ($45^{\circ}$ and $90^{\circ}$). Results: There was significant group and time interaction effect for VMO and VL muscle activation at $45^{\circ}$ knee flexion. This was similarly demonstrated at $90^{\circ}$ knee flexion. No significant group main effect and time main effect for VMO and VL muscle activation were noted at $45^{\circ}$ knee flexion, respectively. In contrast, there was significant group main effect and time main effect for VMO and VL muscle activation at $90^{\circ}$ knee flexion. These significant differences were demonstrated through two-way analysis of variance over repeated measurements, suggesting that the EMG activity of the VMO muscle during squatting with a gym ball showed remarkable improvement compared to that of the VL muscle. Conclusion: This research suggests that squat exercise using a gym ball may be more beneficial in improving the activity of VMO than of the VL muscle at both $45^{\circ}$ and $90^{\circ}$ of knee flexion, respectively. We highly recommend squat exercises with a gym ball for selective strengthening of the VMO muscle in knee rehabilitation.