Patellar taping does not affect the onset of activities of vastus medialis obliquus and vastus lateralis before and after muscle fatigue

OBJECTIVE: This study examined the immediate effect of patellar taping with a standard force on the onset of vastus medialis obliquus and vastus lateralis activities before and after muscle fatigue in able-bodied subjects. DESIGN: This study tested 29 mature able-bodied subjects. The surface electromyographic onset time of their vastus medialis obliquus and vastus lateralis was measured after a posteroanterior perturbation at the knee in a single-legged standing position. The measurements were taken under three conditions in random order of true patellar taping, sham patellar taping, and no patellar taping. Afterward, subjects performed a knee-extension exercise until their quadriceps fatigued, and the above tests were repeated to test the effect of fatigue on the outcome. RESULTS: There was no statistically significant difference with patellar taping on the electromyographic onset time of the vastus medialis obliquus and vastus lateralis compared with the placebo-taping and no-taping conditions (P = 0.455). There was no statistically significant difference in onset of vastus medialis obliquus and vastus lateralis muscles before and after muscle fatigue (P = 0.304). CONCLUSIONS: The present study suggests that patellar taping does not enhance the temporal activation of vastus medialis obliquus in both fatigue and nonfatigue conditions on able-bodied subjects.     

The effect of a vastus lateralis tape on muscle activity during stair climbing

Recently taping techniques with the primary purpose of altering muscle activity have become a part of clinical physiotherapy practice. A firmly applied tape across the fibres of the vastus lateralis (VL) muscle has been proposed to decrease the VL muscle activity. The primary aim of this study was to assess the effects of an inhibitory muscle tape applied over the vastus lateralis (VL) muscle during stair climbing. Twenty five subjects without lower limb pathology were recruited. Normalised integrated EMG (IEMG) was analysed from VL, vastus medialis obliquus (VMO), biceps femoris (BF) and soleus muscles during stair climbing. The subjects were assessed during three conditions: no tape (untaped), (no tension) control tape and (tensioned tape) VL inhibitory taping application. There was a significant decrease (p<0.05) in the VL IEMG during the initial stance phase during both stair ascent and descent. The inhibition if the VL muscle occurred with both control and VL inhibitory tape applied. No significant differences (p>0.05) were noted in any of the other muscles assessed. The results demonstrated that there was a significant decrease in the IEMG of the VL both during stair ascent and descent with VL inhibitory tape and control tape applied in normal subjects.     

Temporal activity of vastus medialis obliquus and vastus lateralis in symptomatic knee osteoarthritis

OBJECTIVE: Knee osteoarthritis has a major impact on quadriceps function, yet its effect on the specific temporal recruitment of vastus medialis obliquus and vastus lateralis is unknown. The aim of this study was to determine the electromyographic onset of vastus medialis obliquus activity relative to that of vastus lateralis in individuals with symptomatic knee osteoarthritis and in an asymptomatic control group during the functional task of stair climbing. DESIGN: Cross-sectional, comprising 41 participants with symptomatic knee osteoarthritis and 33 controls matched for age, sex, and body mass. RESULTS: No significant differences were detected in the timing of onset of vastus medialis obliquus relative to that of vastus lateralis between the osteoarthritis and control groups. Radiographic osteoarthritis severity, presence of patellofemoral joint disease, and pain intensity did not seem to influence the temporal relationship of the vastii in the osteoarthritis group. CONCLUSION: The presence of symptomatic, radiographic knee osteoarthritis is not associated with deficits in the temporal recruitment of vastus medialis obliquus and vastus lateralis during stair climbing. This implies that selective retraining of the individual components of the quadriceps is not indicated in rehabilitation programs for patients with this disease.     

Activation of the quadriceps muscle during semisquatting with different hip and knee positions in patients with anterior knee pain.

OBJECTIVE: We measured the surface electromyographic activities of vastus medialis obliquus and vastus lateralis in 16 subjects with patellofemoral joint pain syndrome. DESIGN: Each subject performed bilateral static knee extension exercises at 60% of his or her maximal voluntary effort under different combinations of hip rotation (30 degrees of medial rotation, neutral, 45 degrees of lateral rotation) and knee flexion (20 and 40 degrees) in a standing position. The ratio of surface-integrated electromyographic signals of vastus medialis obliquus over vastus lateralis was calculated for each of the six conditions. Because of significant interaction of hip rotation and knee flexion in the two-way analysis of variance, data were analyzed separately with paired t tests for the effect of knee positions and one-way repeated measures analysis of variance for hip positions. RESULTS: At 20 degrees of knee flexion, there was no significant difference among the three hip positions, whereas at 40 degrees of knee flexion, medial rotation of the hip resulted in significantly higher vastus medialis obliquus over vastus lateralis activity ratio than lateral rotation (P < 0.05). CONCLUSIONS: There was relatively more activation of vastus medialis obliquus than vastus lateralis at 40 degrees of semisquat with the hip medially rotated by 30 degrees. This finding has clinical implications for training the vastus medialis obliquus in patients with patellofemoral joint pain syndrome.     

Effect of two different kinesio taping techniques on knee kinematics and kinetics in young females

[Purpose] The application of kinesio taping may improve strength and performance, inhibit and facilitate motor activity, and increase range of motion. The aim of this study was to compare the effects of kinesio taping facilitation and inhibition applications on spatiotemporal knee kinematics and kinetics during walking activity in healthy subjects. [Subjects and Methods] A three-dimensional quantitative gait evaluation was performed without tape and with, facilitation and inhibition kinesio taping application on the knee. Sixteen healthy female college students (age, 19.7 ± 0.4 years; height, 1.64 ± 3.4 cm; body mass, 51.5 ± 4.8 kg) participated in the study. [Results] Spatiotemporal parameters (cadence, walking speed, stride length) were significantly different among the trials. Knee joint sagittal plane range of motion was not different with either kinesio taping application. Knee external flexion moment during the early stance phase decreased significantly with facilitation kinesio taping and increased with the inhibition kinesio taping. Knee external extension moment during the mid-stance phase increased with facilitation kinesio taping. Knee power parameters, eccentric activity in the rectus femoris during the pre-swing phase was significantly increased with inhibition kinesio taping application, while eccentric activity of the hamstrings during the terminal swing of gait was decreased. [Conclusion] These findings showed that facilitation kinesio taping application affected the terminal stance phase and that inhibition kinesio taping influenced the terminal swing phase compared with the no tape condition.Key words: Kinesio tape, Knee joint, Gait analysis     

A Study on the Differences of Quadriceps Femoris Activities by Knee Alignment during Isometric Contraction

[Purpose] This study attempted to identify how genu varum or valgum affects the electromyographic activities of the vastus medialis, vastus lateralis, and rectus femoris during knee isometric contraction. [Subjects] Fifty-two healthy young adults were enrolled in this study. They were enrolled and classified into three groups by knee alignment conditions: the genu varum, genu valgum, and control groups. [Methods] The electromyographic activity ratio of the vastus medialis to the vastus lateralis and rectus femoris were calculated using the percentage of maximum voluntary contraction. The participants contracted their quadriceps during isometric contraction at 30 and 60° of knee flexion. [Results] The genu varum group had more activity in the vastus medialis than in the vastus lateralis and rectus femoris, whereas the genu valgum group had more activity in the vastus lateralis and rectus femoris than in the vastus medialis. There was a significant difference in the muscle activity ratio between the vastus medialis and vastus lateralis by angle of knee flexion degree only in the genu valgum. There were no significant differences in any of the three groups in terms of the muscle activity ratio of the vastus medialis to the rectus femoris by angle of knee flexion. [Conclusion] The quadriceps femoris was used for different strategies according to knee alignment during isometric contraction at 30 and 60°. This study suggests that rehabilitation training programs used to strengthen the quadriceps should consider the knee alignment conditions of the target subjects.Key words: Electromyography, Quadriceps muscle, Isometric contraction     

Activation of the vastus medialis oblique and vastus lateralis muscles in asymptomatic subjects during the sit-to-stand procedure

[Purpose] The purpose of this study was to examine the vastus medialis oblique to vastus lateralis ratio in two pelvic tilt positions while performing the sit-to-stand task. [Subjects and Methods] Activation of the vastus medialis oblique and the vastus lateralis muscles of 46 healthy subjects (25 males, 21 females) were recorded by surface electromyography during the STS task with anterior pelvic tilt (sit with thoracolumbar spine extended and pelvis in an anterior tilt) and neutral pelvic tilt (sit with thoracolumbar spine relaxed and pelvis in the neutral tilt position) positions. Changes in vastus medialis oblique, vastus lateralis activation and the vastus medialis oblique/vastus lateralis ratio were analyzed. [Results] Vastus medialis oblique and vastus lateralis muscle activation significantly increased in neutral pelvic tilt position, but the vastus medialis oblique/vastus lateralis ratio was not statistically different. [Conclusion] The sit-to-stand procedure with neutral pelvic tilt position increased activation of the vastus medialis oblique and vastus lateralis, usefully strengthening the quadriceps, but did not selectively activate the vastus medialis oblique muscle.Key words: Anterior pelvic tilt, Neutral pelvic tilt, Sit-to-stand task     

股内侧斜肌在髌股关节不稳中作用的影像学研究进展

髌股关节不稳在年轻人群中常见,诸多因素可致髌股关节不稳,其中动力因素中股内侧肌与股外侧肌协调性不一致是重要原因之一。髌股关节不稳会对肌肉生物力学及功能状态造成影响,进一步导致临床常见的髌股关节疼痛。利用影像学技术评估股内侧斜肌在髌股关节不稳中的功能变化及早期指导临床治疗是现阶段研究的热点。本文对股内侧斜肌在髌股关节不稳患者中的作用及相关影像学研究进展进行综述。     

Electromyographic activity of the quadriceps components during the final degrees of knee extension

An imbalance in the recruitment patterns of the quadriceps muscle has been implicated in patellofemoral knee pain; however ambiguity remains in the normal recruitment patterns of this muscle. We investigated the activity of the quadriceps muscle during the final degrees of knee extension, specifically in the medial and lateral components. Sixteen healthy subjects (age; 22.5 (± 3.4) years, body mass; 67.5 (± 12.1) kg and height; 173.9 (± 10.4) cm) participated.Torque and electromyographic (EMG) activity of the quadriceps muscle were measured during isokinetic and isometric knee extensions. Torque and EMG activity reduced in all component muscles during the final degrees of isokinetic extension, but this did not occur during isometric contractions at similar angles. Normalised activity of rectus femoris (RF) was greater than that of vastus lateralis (VL) and vastus medialis obliquus (VMO) during the final degrees of isokinetic knee extension at 30°/sec; there were no differences between any component muscles at the higher velocities. VMO:VL and vastus medialis longus (VML):VL ratios were unchanged during knee extensions, except that VML:VL ratio increased significantly during the final degrees of extension at 30°/sec. Future work should compare these results with people with anterior knee pain, and explore this further during activities of daily living.     

Effect of foot orthotics on quadriceps and gluteus medius electromyographic activity during selected exercises

OBJECTIVE: To compare electromyographic activity of the vastus medialis, vastus lateralis, and gluteus medius during functional activities in subjects with different foot types while wearing various off-the-shelf foot orthotics. DESIGN: Experimental, controlled; 3 foot-type groups (pes planus, pes cavus, pes rectus) each tested in 4 orthotic conditions while performing 3 different exercises. SETTING: Laboratory. PARTICIPANTS: Thirty healthy young adults, 10 with each foot type. INTERVENTIONS: Four conditions: no orthotic, 7 degrees medial rearfoot post, 4 degrees lateral rearfoot post, and neutral rearfoot post. MAIN OUTCOME MEASURE: Surface electromyographic activity for the vastus medialis, vastus lateralis, and gluteus medius during single-leg squatting, lateral stepdown, and maximum vertical jump exercises. RESULTS: Greater vastus medialis and gluteus medius activity was found with all 3 orthotic conditions, regardless of subject foot type, during the single-leg squat and lateral stepdown. Less vastus lateralis activity was found with the vertical jump with all orthotic conditions, again regardless of foot type. CONCLUSIONS: During slow controlled exercises such as the single-leg squat and lateral stepdown, vastus medialis and gluteus medius activity may be enhanced with an off-the-shelf orthotic, regardless of posting or foot type. These same findings do not appear to carry over to a more explosive task such as the maximal vertical jump.     

Patellar kinematics, part I: the influence of vastus muscle activity in subjects with and without patellofemoral pain

BACKGROUND AND PURPOSE: Reduced motor unit activity of the vastus medialis muscle relative to the vastus lateralis muscle has been implicated as a cause of lateral patellar subluxation. The purpose of this study was to assess the influence of vastus muscle motor unit activity on patellar kinematics. SUBJECTS: Twenty-three women (mean age=26.8 years, SD=8.5, range=14-46) with a diagnosis of patellofemoral pain and 12 women (mean age=29.1 years, SD=5.0, range=24-38) without patellofemoral pain participated. Only female subjects were studied because of potential biomechanical differences between sexes. METHODS: Patellar kinematics (kinematic magnetic resonance imaging) and vastus muscle electromyographic (EMG) activity using indwelling electrodes were measured during resisted knee extension. Measurements of medial and lateral patellar displacement and tilt obtained from magnetic resonance images were correlated with normalized vastus lateralis:vastus medialis oblique muscle and vastus lateralis:vastus medialis longus muscle EMG ratios at 45, 36, 27, 18, 9, and 0 degrees of knee flexion using a stepwise regression procedure. RESULTS: The vastus lateralis:vastus medialis longus muscle EMG ratio contributed to the prediction of lateral patellar glide at 27 degrees of knee flexion (r=-.48), with increased vastus medialis longus muscle activity being associated with greater lateral patellar displacement. A similar inverse relationship was evident with lateral patellar tilt at 36, 27, 18, and 9 degrees of knee flexion. CONCLUSION AND DISCUSSION: These results suggest that increased motor unit activity of the vastus medialis muscle appears to be associated with abnormal patellar kinematics in women, but it is not necessarily a cause of abnormal patellar kinematics.     

Differences of quadriceps activity during inline lunge by using FMS assessment

[Purpose] This study assessed the exercise capacity of healthy adults while performing the inline lunge exercise by using Functional Movement Screen (FMS). Compared the difference in muscle activity of the quadriceps according to the exercise capacity. [Participants and Methods] Thirty two healthy participants (12 males, 20 females) participated in this study. The surface electromyography (sEMG) was used to measure the electrical activities for the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL) of quadriceps. [Results] Both groups had significant difference when sitting up and getting up during the inline lunge. In scores 3 group, vastus medialis showed higher muscle activity than vastus lateralis. On contrary, in scores 2 group, vastus lateralis had higher muscle activity than vastus medialis. [Conclusion] Therefore, this study suggests that inline lunge can help to strengthen the quadriceps effectively by showing the difference of quadriceps activity according to exercise capacity.Key words: Inline lunge, Muscle activity, Functional movement screen     

Altered vastii recruitment when people with patellofemoral pain syndrome complete a postural task

OBJECTIVE: To investigate the recruitment of the vastus medialis obliquus (VMO) and vastus lateralis during voluntary tasks that challenge the stability of the knee and to evaluate whether there is a change in the coordination of the postural response by the central nervous system in subjects with patellofemoral pain syndrome (PFPS). DESIGN: Cross-sectional. SETTING: University laboratory in Australia. PARTICIPANTS: Thirty-seven subjects with PFPS and 37 asymptomatic sex-matched controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Recordings of electromyographic activity of the VMO, vastus lateralis, tibialis anterior, and soleus were made by using surface electrodes. Subjects rose onto their toes (rise task) or rocked back on their heels (rock task) in a visual choice-reaction time task. Electromyographic onsets were determined by using a computer algorithm and were verified visually. RESULTS: Our results confirm that, in asymptomatic subjects, contraction of the VMO and vastus lateralis occurs as part of the feed-forward postural response associated with ankle movements in standing, and the contraction of these separate heads of the quadriceps group occurs simultaneously. However, when subjects with PFPS perform identical tasks, the electromyographic onset of the vastus lateralis occurs before that of the VMO. CONCLUSION: These findings indicate a difference in motor control in subjects with PFPS. They also support the hypothesized relation between changes in the timing of activity of the vastii and PFPS and provide the theoretic rationale to support physiotherapy treatment commonly used in the management of PFPS.     

Electromyographic effects of foot orthotics on selected lower extremity muscles during running.

OBJECTIVE: To study the effects of foot orthotics on the mean electromyographic amplitude of proximal and distal lower extremity muscle groups during the first 50% of the stance phase during treadmill running. DESIGN: Repeated measures. SETTING: Subjects were recruited from the general community. PARTICIPANTS: Twelve recreational runners who were symptomatic for lower extremity pain. Clinical and radiographic findings confirmed the presence of structural malalignment of the foot. INTERVENTION: Semirigid orthotics were fabricated for each subject, and like footwear provided. MAIN OUTCOME MEASURES: Surface electromyogram activity from the tibialis anterior, medial gastrocnemius, vastus medialis, vastus lateralis, and biceps femoris was collected during treadmill running at self-selected speeds for orthotic and nonorthotic conditions. Root mean square values were averaged across 10 cycles, normalized to time and expressed as a percentage of the nonorthotic condition. RESULTS: Paired t test results showed statistically significant changes (p<.05) for the biceps femoris (-11.1%) and tibialis anterior (+37.5%) muscle groups during the orthotic condition. Electromyographic activity in the medial gastrocnemius, vastus medialis, and vastus lateralis with orthotic use was not significantly different from the nonorthotic condition. CONCLUSION: Although subjects' electromyographic responses to orthotic use were highly individualized, the findings of this study may enhance our understanding of muscle activity changes associated with positive outcomes from orthotic use.     

Activities of the Vastus Lateralis and Vastus Medialis Oblique Muscles during Squats on Different Surfaces

[Purpose] The purpose of the present study was to examine the effects of squat exercises performed on different surfaces on the activity of the quadriceps femoris muscle in order to provide information on support surfaces for effective squat exercises. [Subjects and Method] Fourteen healthy subjects performed squat exercises for five seconds each on three different support surfaces: hard plates, foam, and rubber air discs. Their performance was measured using electromyography. As the subjects performed the squat exercises on each surface, data on the activity of the vastus medialis oblique and the vastus lateralis, and the vastus medials oblique/vastus lateralis ratio, were collected. [Results] The activity of the vastus medialis oblique and the vastus medialis oblique/vastus lateralis ratio were found to be statistically significantly higher on rubber air discs than when the squats were performed on hard plates or foam. [Conclusion] To activate the vastus medialis obilique, and to enhance the vastus medialis oblique/vastus lateralis ratio, unstable surfaces that are highly unstable should be selected.Key words: Support surfaces, Vastus medialis obilique, Vastus lateralis     

The effect of stretching exercises on the fibre angle of the vastus lateralis and vastus medialis oblique: an ultrasound study

[Purpose] To investigate the effects of a seven-week quadriceps stretching program on the muscle fibre orientation of the vastus medialis oblique and vastus lateralis in the lower limbs by ultrasound imaging. [Participants and Methods] Twenty-seven healthy, physically fit, asymptomatic females and males (age 21.5 ± 1.3, Tegner activity level score ≥4) were recruited. Their initial vastus medialis oblique and vastus lateralis fibre angles were determined using ultrasound. They then undertook a seven-week quadriceps stretching program, 3 sets of stretches to be performed on both lower limbs, 3 times a week on 3 separate days. One volunteer was assigned as an intra-rater control and did not take part in the stretching program. The vastus lateralis and vastus medialis oblique fibre angles were measured again on completion of the exercise regime. [Results] A statistically significant decrease in muscle fibre angle was observed in both the right and left vastus medialis oblique, and the right and left vastus lateralis. [Conclusion] A 7-week stretching program can result in a significant decrease in muscle fibre angle in both the vastus medialis oblique and the vastus lateralis. This can help in understanding the effects of prescribed stretching exercises on athletic patients with PFP.     

Comparison of muscle activation levels and knee valgus between individuals with medial patellofemoral ligament reconstruction and healthy individuals during fatiguing step down task

BackgroundMedial patellofemoral ligament reconstruction becomes first-choice surgical procedure for patients with a history of lateral patellar dislocations but there is limited knowledge about neuromuscular activation patterns of individuals with a history of patellar dislocation who underwent medial patellofemoral ligament reconstruction.ObjectiveThe aim of this study was to compare muscle activation levels and knee valgus during step down performance test between individuals with a history of medial patellofemoral ligament reconstruction and healthy individuals.MethodsFifteen individuals with medial patellofemoral ligament reconstruction and 15 healthy individuals were included. Vastus medialis obliquus, vastus lateralis and gluteus medius muscle activation levels and knee valgus were measured during 60-s- step down performance test. Two-way repeated-measures of analysis of covariance was used for statistical analysis.FindingsCompared to the healthy individuals, individuals with medial patellofemoral ligament reconstruction showed lower vastus medialis obliquus (p = .04) and gluteus medius (p = .005) activation levels, and higher knee valgus (p = .002) in last period of the step down performance test.InterpretationSince the significant results were only observed in the fatiguing section of the test, endurance tests may provide more information about neuromuscular control of the individuals with history of medial patellofemoral ligament reconstruction. Future studies should investigate whether endurance exercises that target to improve vastus medialis obliquus and gluteus medius activity result in better clinical outcomes than conventional programs for individuals with medial patellofemoral ligament reconstruction.     

Motor unit synchronization of the vasti muscles in closed and open chain tasks

OBJECTIVES: To investigate motor unit synchronization between medial and lateral vasti and whether such synchronization differs in closed and open chain tasks. DESIGN: Electromyographic recordings of single motor unit action potentials were made from the vastus medialis obliquus (VMO) and multiunit recordings from vastus lateralis during isometric contractions at 30 degrees of knee flexion in closed and open chain conditions. SETTING: Laboratory. PARTICIPANTS: Five volunteers with no history of knee pain (age, 30+/-3.32 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The degree of synchronization between motor unit firing was evaluated by identifying peaks in the electromyographic averages of the vastus lateralis, triggered from motor unit action potentials in the VMO, and the proportion of power in the power spectral density of the triggered average at the firing frequency of the reference motor unit. The proportion of cases in which there was significant power and peaks in the triggered averages was calculated. RESULTS: The proportion of trials with peaks in the triggered averages of the vastus lateralis electromyographic activity was greater than 61.5% in all tasks, and there was a significantly greater proportion of cases where power in the spectrum was greater than 7.5% ( P =.01) for the closed chain condition. CONCLUSIONS: There was a high proportion of synchronized motor units between the 2 muscles during isometric contractions, with evidence for greater common drive between the VMO and vastus lateralis in closed chain tasks. This has implications for rehabilitation because it suggests that closed chain tasks may generate better coordination between the vasti muscles.     

Changes in muscle activity during fast, alternating flexion-extension movements of the knee

The effects of high frequency alternating knee flexion-extension on muscle activity of the quadriceps and hamstring muscle groups has been investigated. Standard loads were used for each subject. The muscle activity in vastus medialis, vastus lateralis, rectus femoris and the lateral hamstrings were recorded by electromyography during increasing velocities. Rectus femoris and hamstrings were found to increase their activities significantly with increasing speed while vastus medialis and vastus lateralis showed no such change. The individual thigh muscles thus differ in function in relation to the velocity of movement.     

Effects of squats accompanied by hip joint adduction on the selective activity of the vastus medialis oblique

[Purpose] This study evaluated the effective selective activation method of the vastus medialis oblique for knee joint stabilization in patients with patellofemoral pain syndrome. [Subjects and Methods] Fifteen healthy college students (9 males, 6 females); mean age, height, and weight: 22.2 years, 167.8 cm, and 61.4 kg, respectively) participated. The knee angle was held at 60°. Muscle activities were measured once each during an ordinary squat and a squat accompanied by hip joint adduction. The muscle activities of the vastus medialis oblique and vastus lateralis were measured by electromyography for five seconds while maintaining 60° knee flexion. Electromyography signals were obtained at a sampling rate of 1,000 Hz and band pass filtering at 20–50 Hz. The obtained raw root mean square was divided by the maximal voluntary isometric contraction and expressed as a percentage. The selective activity of the vastus medialis oblique was assessed according to the muscle activity ratio of the vastus medialis oblique to the vastus lateralis. [Results] The activity ratio of the vastus medialis oblique was higher during a squat with hip joint adduction than without. [Conclusion] A squat accompanied by hip joint adduction is effective for the selective activation of the vastus medialis oblique.Key words: Patellofemoral pain syndrome, Vastus medialis oblique, Squat