• Physical Therapy Korea
• /
• v.23 no.2
• /
• pp.75-83
• /
• 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
• /
• v.12 no.2
• /
• pp.11-19
• /
• 2005

Patellofemoral pain syndrome (PFPS) is often attributed to malalignment and maltracking of patella within the patellofemoral joint. Most exercise for PFPS has focused on selectively strengthening the vastus medialis oblique muscle (VMO). This study was designed to identify the effect of medial, lateral wedge and difference of Quadriceps angle (Q-angle) on vastus medialis oblique/vastus lateralis muscle (VL) activity ratios. The subjects were twenty young adult males who had not experienced any knee injury. They were asked to perform isometric contraction exercises in three postures using medial and lateral wedge. The EMG activity of the VL and VMO were recorded in three postures by surface electrodes and normalized by %MVC values derived from seated, isometric knee extensions. The normalized EMG activity levels (%MVC) of the VL and VMO for the three postures of the lower extremities were compared using 2-way repeated measures ANOVA with 1 between-subject factor (group), and 1 within-subject factor (wedge). Results of repeated measures of ANOVA's revealed that the medial wedge isometric contraction exercise produced significantly greater EMG activity of VMO/VL ratios in Group I (Q-angle $18^{\circ}$ or less) (p<.05). But, the medial wedge isometric contraction exercise was no significant difference of VMO/VL ratios in Group II (Q-angle $19^{\circ}$ or more) (p>.05). These results have important implications for selective VMO muscle strengthening exercises in PFPS patients.

• The Journal of Korean Physical Therapy
• /
• v.22 no.4
• /
• pp.21-28
• /
• 2010

Purpose: The purpose of this study was to evaluate the electromyographic (EMG) activity of vastus medialis oblique (VMO) and vastus lateralis (VL) muscles on foot position and knee angle for hemiplegia patients. Methods: Ten stroke subjects (10 males) participated in the study. Subjects were all right-hemiplegic patients. All subjects did $0^{\circ},\;20^{\circ}$ and $40^{\circ}$ knee flexion while maintaining the foot in a neutral position, or at $30^{\circ}$ adduction or at $30^{\circ}$ abduction. Surface EMG data were collected for VMO and VL muscles on the non-hemiplegic side and hemiplegic side. Collected data were analyzed using two-way ANOVA. Results: VMO and VL activities for the non-hemiplegic and the hemiplegic sides were highest for $40^{\circ}$ knee flexion while maintaining the three foot positions. There were no significant differences in EMG activity of the VMO and VL muscles with different foot positions. There were significant differences between VMO and VL activity for knee flexion angle while maintaining the foot in neutral (p<0.05), at $30^{\circ}$ adduction (p<0.05), or at $30^{\circ}$ abduction (p<0.05). Conclusion: Foot position does not influence VMO and VL activities. But, knee flexion exercise in a closed chain can increase VMO and VL muscle activity for hemiplegic patients. In particular, VMO and VL activities for both the non-hemi side and the hemi side were highest for $40^{\circ}$ knee flexion.

• PNF and Movement
• /
• v.17 no.1
• /
• pp.137-144
• /
• 2019

Purpose: This study examined the effects of the abdominal drawing-in maneuver (ADIM) on muscle activity in the trunk and legs while subjects walk on a ramp. Methods: The subjects were healthy adult males (n=15) and females (n=8) in their twenties. The subjects were asked to maintain the ADIM contraction for 15 minutes using a pressure biofeedback unit. Their muscle activity was then measured while ascending or descending the ramp with or without the ADIM contraction maintained. Activity in the sternocleidomastoid, splenius capitis, rectus abdominis, external oblique abdominal, transversus abdominis, erector spinae, vastus medialis, and vastus lateralis muscles was measured using surface electromyography (TM DTS, Noraxon, USA). A paired t-test was conducted using SPSS 18.0 (IBM) for statistical data processing. Results: Maintaining the ADIM contraction during ascension led to a significant increase (p<0.05) in muscle activity for the rectus abdominis, transversus abdominis, vastus medialis, and vastus lateralis, but a significant decrease (p<0.05) in muscle activity for the erector spinae, when compared to the same activity without the ADIM maintained. Furthermore, maintaining the ADIM contraction during descent led to a significant increase (p<0.05) in muscle activity for the rectus abdominis, external abdominal oblique, transversus abdominis, vastus medialis, and vastus lateralis, but a significant decrease (p<0.05) in muscle activity for the erector spinae, when compared to the same activity without the ADIM maintained. Conclusion: As a result of this study, it maintains the ADIM and reduces lumbar muscle activity at the waist and increases muscle activity in the legs when walking on a ramp. Therefore, maintaining the ADIM contraction during ramp walking is recommended as training to improve the function of patients' muscular skeleton.

• The Journal of Korean Physical Therapy
• /
• v.17 no.2
• /
• pp.38-45
• /
• 2005

This study was deigned to identify the effect of electromyographic activity of knee extensor during contralateral hip isometric adduction. six young adults who had not experienced any knee injuries were recruited. Their Q-angles were within a normal rage. They were asked to sit on the table. The EMG activities of the vastus lateralis (VL), vastus medialis oblique (VMO) were recorded in sitting by surface electrodes and normalized by MVC EMG values derived from manual muscle test. The EMG activity levels of the VL, RF, and VMO were the highest when foot was externally rotated. The EMG activity level of VMO/VL ratio did show significant differences(p<.05). The onset time of vastus lateralis (VL) and vastus medialis oblique (VMO) was similar in contralateral hip isometric adduction(p<.05).

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.19 no.2
• /
• pp.55-60
• /
• 2013

Background: The purpose of this study was to determine if there is a difference in activation of the rectus femoris, vastus medialis oblique, vastus lateralis, semitendinosus, and biceps femoris when performing normal free squat with standinding position and free squat with $30^{\circ}$ flexed hip joint. Methods: Electromyograph surface electrodes were placed on the rectus femoris, vastus medialis oblique, vastus lateralis, semitendinosus, and biceps femoris of 19 healthy college students. The participants performed standing bilateral squats and standing bilateral squats with $30^{\circ}$ flexed hip joint with EMG measures taken upon initiation of muscle activity as confirmed by an electronic goniometer. Participants completed one trial with the EMG time measurements on each type. Results: There was a significant difference between normal squats(standing squats) and normal squats with $30^{\circ}$ flexed hip joint. The normal squat exercise was statistically higer than normal squat exercise with $30^{\circ}$ flexed trunk except for semitendinosus and biceps femoris that shown slightly high. Conclusions: As a result of this study, there were increases of muscle activity in both ways. In particular, it may be more beneficial for knee joint stabilization to perform normal squat exercise with standing position relatively.

• The Journal of Korean Physical Therapy
• /
• v.20 no.3
• /
• pp.35-43
• /
• 2008

Purpose: We investigated the effect of isometric resistance exercise on the vastus medialis oblique muscle with inelastic tape and EMG biofeedback training applied to the patello-femoral joints of patients with patella malalignment. Methods: The 39 elderly subjects that had patella malalignment but no neuromuscular disorders were divided into a control group, taping group, and EMG biofeedback training group. Evaluations of function improvement performed before and after the treatment, as well as 4 weeks after treatment. Results: Change in pain in the knee joint were significantly different among groups (p<0.05). Maximum voluntary isometric contractility in the quadriceps muscle was significantly in the EMG biofeedback group (p<0.001). The WOMAC (Western Ontairo & McMaster Questionnaire) index showed a significant change (p<0.05) in pain, function, and total score. Taping and EMG biofeedback training showed a lasting effect until measurement 4 weeks after treatment. SF-36 (Medical outcome short form-36), which assesses the quality of life, did not significantly change. Conclusion: In osteoarthritis patients with a loss of patello-femoral joint function, isometric resistance exercise of the vastus medialis oblique muscle with taping seems effective.

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

• PNF and Movement
• /
• v.21 no.2
• /
• pp.231-241
• /
• 2023

Purpose: Weakness of the vastus medialis oblique muscle (VMO), or the imbalance between VMO and vastus lateralis muscle (VL) activity, is one of the most important factors in knee joint problems. Rigid taping techniques, such as patellar inhibition taping and VL inhibition taping, are frequently used in clinical practice to treat knee joint problems. The purpose of this study was to compare the acute effect of three different types of taping (patellar inhibition taping (PIT), distal VL inhibition taping (DVLIT), and proximal VL inhibition taping (PVLIT)) on electromyography (EMG) activity of VMO, VL, and VMO:VL ratio during walking. Methods: Thirty-eight normal healthy subjects (38 males; mean age = 31.00 years) voluntarily participated in this study. EMG was applied to investigate muscle activation during walking. Repeated measures of ANOVA and one-way ANOVA compared the three different conditions (PIT, DVLIT, and PVLIT) for each variable. Results: VMO and VL activation were significantly increased after PTIT application, and VMO and VL activation were significantly decreased after DVLIT and PVLIT application. The VMO:VL ratio increased after the three types of taping application, but there were no significant differences among the three types of taping. Conclusion: Based on the results of this study, PTIT is more effective than DVLIT and PVLIT in increasing the muscle activation of the VMO and VL during walking. Also, DVLIT is more effective for increasing the VMO:VL ratio and has beneficial effects on the imbalance between VMO and VL activity.

• Physical Therapy Korea
• /
• v.26 no.1
• /
• pp.75-83
• /
• 2019

Background: A tight iliotibial band (ITB) may lead to lateral patellar maltracking, compression, and tilt, and dominant vatus lateralis (VL) muscle activation relative to vastus medialis oblique (VMO) can laterally displace the patella, which leads to anterior knee pain. Therefore, an effective management technique is needed to stabilize the patella in individuals with tight ITB. Increased stability during the modified Thomas test has the potential to decrease compensatory motion and thus to selectively stretch the ITB. Objects: The purpose of this study was to determine the effects of ITB stretching in the modified Thomas test position on ITB flexibility, patellar translation, and muscle activities of the VMO and VL during quadreceps-setting (QS) exercise in individuals with tight ITB. Methods: Twenty-one subjects with tight ITB were recruited. Digital inclinometer was used to measure the hip adduction angle during the modified Ober test. Universal goniometer was used to measure the hip abduction angle during the modified Thomas test. Ultrasonography was used to measure the patella-condylar distance. Electromyography was performed to collect data of muscle activities. Paired t-test was used to determine the statistical significance between pretest and posttest. Results: The range of hip adduction in modified Ober test increased (p=.04) and the range of hip abduction in the modified Thomas test decreased after ITB stretching (p<.01). There was no difference between lateral patellar translation (p=.18). VMO muscle activity significantly increased after ITB stretching during QS (p<.01). VL muscle activity had no difference after stretching. Conclusion: The ITB stretching in the modified Thomas test position can be suggested as a management method for improving ITB flexibility and VMO muscle activity in individuals with tight ITB.