Vastus lateralis and vastus medialis obliquus muscle activity during the application of inhibition and facilitation taping techniques

OBJECTIVE: To evaluate the effect of inhibition and facilitation taping techniques on the activity of vastus lateralis and vastus medialis obliquus. DESIGN: Repeated-measures design. SETTING: Laboratory in an educational institution. SUBJECTS: Thirty healthy females aged between 18 and 23 years. INTERVENTION: Subjects were tested during the application of inhibition tape, facilitation tape and no tape to vastus lateralis in random order. MAIN OUTCOME MEASURES: Electromyographic activity of vastus lateralis and vastus medialis obliquus during stair descent was recorded using bipolar surface electrodes. RESULTS: Electromyographic activity of vastus lateralis and vastus medialis obliquus during the application of inhibition tape or facilitation tape did not alter significantly compared with no tape condition. CONCLUSIONS: Taping designed to inhibit or facilitate muscle activity via sensory stimulation does not affect vastus lateralis or vastus medialis obliquus activity in healthy subjects. Further investigation is required to find a means of muscle taping that could be recommended as an intervention for patients with patellofemoral pain syndrome.     

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.     

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.     

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.     

An electromyographical study to investigate the effects of patellar taping on the vastus medialis/vastus lateralis ratio in asymptomatic participants

It is commonly theorised that patellofemoral pain syndrome (PFPS) is caused by maltracking due to vastus medialis (VM) weakness relative to the vastus lateralis (VL). Despite this being a controversial theory, patellar taping is a commonly used technique that purports to correct this muscle imbalance by increasing the VM/VL ratio. The effects of different forms of taping on vasti muscle activity are still not known. The objective of this study was to investigate the effects of three different types of patellar taping on the VM/VL ratio in asymptomatic university students. Each participant performed a set of four single-legged squats under four separate taping conditions: A) medial, B) lateral, C) neutral, and D) no-tape. The condition sequence was randomised. The main outcome measure was the normalised VM/VL ratio, assessed by using surface electromyography. Secondary outcome measures were the normalised EMG activity of the VM and the VL. A convenience sample of 24 (17 females) students (22 +/- 10 years, M +/- SD) completed this study. The lateral taping condition produced small but significantly greater VM/VL ratios than the medial (p = 0.007) and neutral (p = 0.007) but not the no-tape (p = 0.123) condition. There were no significant differences between the medial, neutral, and no-tape conditions. These results question whether patellar taping can impart a clinically significant effect on the VM/VL ratio. The results of this study cannot be directly extrapolated to a patient population, and further research in the PFPS population is required before clinical recommendations can be made.     

髌股关节疼痛及其临床治疗的研究

概述过去十年作者在实验室进行有关髌股关节及髌股关节疼痛综合征(PFPS)的研究,研究了正常人髌股关节的几个指标及PFPS患者的康复成效。研究结果反映股内侧肌(VMO)对于控制髌股关节的压力分布所发挥的力学作用、下肢方位对促进VMO募集的影响,以及髌骨叩压、股四头肌的疲劳恢复与生物反馈辅助对PFPS康复治疗的作用。     

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.     

EMG activity of the vastus medialis oblique and the vastus lateralis in their role in patellar alignment

Using intramuscular electrodes the integrated electromyographic activity of the vastus medialis oblique and the vastus lateralis was examined in twenty normal females. The activity was recorded during the last thirty degrees of distal segment stabilized knee extension, when patellar subluxation commonly occurs. The electromyographic activity was normalized and expressed as a percentage of a maximal isometric contraction. Both muscles exhibited low levels of activity with no significant differences between the two. This study provides a quantitative method to assess whether muscular imbalance is present in patients with patellar subluxation.     

An electromyographical study to investigate the effects of patellar taping on the vastus medialis/vastus lateralis ratio in asymptomatic participants

It is commonly theorised that patellofemoral pain syndrome (PFPS) is caused by maltracking due to vastus medialis (VM) weakness relative to the vastus lateralis (VL). Despite this being a controversial theory, patellar taping is a commonly used technique that purports to correct this muscle imbalance by increasing the VM/VL ratio. The effects of different forms of taping on vasti muscle activity are still not known. The objective of this study was to investigate the effects of three different types of patellar taping on the VM/VL ratio in asymptomatic university students. Each participant performed a set of four single–legged squats under four separate taping conditions: A) medial, B) lateral, C) neutral, and D) no-tape. The condition sequence was randomised. The main outcome measure was the normalised VM/VL ratio, assessed by using surface electromyography.

Secondary outcome measures were the normalised EMG activity of the VM and the VL. A convenience sample of 24 (17 females) students (22 ± 10 years, M ± SD) completed this study. The lateral taping condition produced small but significantly greater VM/VL ratios than the medial (p = 0.007) and neutral (p = 0.007) but not the no-tape (p = 0.123) condition. There were no significant differences between the medial, neutral, and no-tape conditions. These results question whether patellar taping can impart a clinically significant effect on the VM/VL ratio. The results of this study cannot be directly extrapolated to a patient population, and further research in the PFPS population is required before clinical recommendations can be made.     

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     

The influence of weakness in the vastus medialis oblique muscle on the patellofemoral joint: an in vitro biomechanical study

OBJECTIVE: Investigation of the influence of weakness in the vastus medialis oblique muscle on patellar tracking. DESIGN: In vitro biomechanical study. BACKGROUND: Currently, the influence of weakness in the vastus medialis oblique muscle on patellar tracking has not been well understood. METHODS: Seven human cadaveric knees were used. The direction of loading forces in the rectus femoris/vastus intermedius, vastus medialis oblique, and the vastus lateralis muscles was decided by the muscle alignment of each cadaver knee measured at the time of dissection. The loads used were 60 N in the rectus femoris, 50 N in the vastus lateralis, and 40 N in the vastus medialis oblique, according to the ratio calculated from the cross-sectional study. The weakness of vastus medialis oblique was simulated at 30 N (75%), 20 N (50%), 10 N (25%), and 0 N (0%), and the patellar position was measured for each condition using a magnetic 3 Space Tracker System. The influence of weakness in the vastus medialis oblique muscle on patellar position was investigated with seven cadaver knees using a magnetic 3 Space Tracker System. RESULTS: At 0 degrees and 15 degrees of knee flexion, 75%, 50%, 25% and 0% of the normal vastus medialis oblique muscle led to a significant difference in lateral patellar shift compared to the normal (P<0.05). CONCLUSIONS: Weakness of the vastus medialis caused the patellar lateral shift at 0 degrees and 15 degrees of knee flexion. RELEVANCE: Weakness of the vastus medialis is thought to be an important factor causing patellar subluxation and dislocation. Understanding the relationship between the vastus medialis weakness and patellar tracking will be useful in diagnosis, treatment and prevention of patellar subluxation and dislocation.     

A novel method for measuring electromechanical delay of the vastus medialis obliquus and vastus lateralis

Electromechanical delay (EMD) of the vastus medialis obliquus (VMO) and vastus lateralis (VL) is determined by measuring the interval between the time of onset of muscle activities and the time of onset of mechanical output. However, individual mechanical output of the VMO or the VL cannot be obtained with the conventional method because of the knee extension force as the mechanical output. Therefore, the objective of the present study was to develop a new method for measuring EMD of the VMO and VL individually. Twelve healthy volunteers participated in the experiment. The motor point of the target muscle was electrically stimulated to evoke a muscle twitch. Simultaneously, the electrical stimulation signal was transmitted to ultrasound apparatus via the electrocardiography input channel. The ultrasound apparatus was used to capture the patellar movement elicited by the muscle twitch. EMD was measured from the onset of the electrical stimulation to the onset of patellar movement. The results showed that the intraclass correlation coefficients for the reproducibility of the EMD measurements of the VMO and VL were greater than 0.8. The EMDs of the VMO and VL were 18.3 +/- 2.2 ms and 24.8 +/- 5.8 ms, respectively. This new method provides a more precise measurement of EMD in the VMO and VL than does the conventional method because of the use of patellar movement as the mechanical output.     

Comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patellofemoral pain

The purpose of this study was to compare vastus medialis obliquus:vastus lateralis muscle (VMO:VL) integrated electromyographic (IEMG) ratios of healthy subjects and patients with unilateral patellofemoral pain (PFP) under isotonic and isometric quadriceps femoris muscle contraction conditions. Subjects ranging in age from 18 to 35 years (mean = 28.06, SD = 5.97) were assigned to one of three groups on the basis of type of knee condition. In group 1, which consisted of seven healthy control subjects with no history of knee pathology, both knees were tested. In group 2, which consisted of nine patients with unilateral PFP, only the painful knee was tested. In group 3, which consisted of the same nine patients who comprised group 2, only the nonpainful knee was tested. Nonnormalized and normalized VMO:VL IEMG ratios were computed for ascending stairs, descending stairs, submaximal isometric contraction, and maximal isometric contraction (nonnormalized only). A two-way analysis of variance for repeated measures indicated VMO:VL ratios for isotonic stair-climbing activities were significantly greater than VMO:VL ratios for isometric contractions. Nonnormalized VMO:VL ratios in group 1 were significantly greater than nonnormalized VMO:VL ratios in the other two groups. Patients with PFP may have abnormal VMO:VL activation patterns, and isotonic quadriceps femoris muscle exercise may elicit more favorable muscle activation patterns than isometric exercise for patients with PFP.     

Relationship between the EMG ratio of muscle activation and bony structure in osteoarthritic knee patients with and without patellar malalignment.

OBJECTIVE: The aim of this study was to compare muscle activation patterns and patellofemoral joint morphologies between patients with knee osteoarthritis with and without patellar malalignment. SUBJECTS: The subjects were divided into 3 groups. Group A comprised 11 patients with symptomatic knee osteoarthritis without patellar malalignment. Group B comprised 14 patients with symptomatic knee osteoarthritis with patellar malalignment. Group C comprised 10 age-matched subjects with non-knee osteoarthritis as controls. METHODS: Isokinetic dynamometry with surface electromyography was used to measure maximal muscle activity in terms of vastus medialis oblique/vastus lateralis ratios. Merchant's view was taken to analyse the bony anatomy of the patellofemoral joint. Recordings were made at angular velocities of 80, 120 and 240 masculine/sec. RESULTS: The electromyographic ratios of group B were lower than groups A and C for all testing velocities (p<0.05). Group B also had larger sulcus angles, lateral patellar tilt and displacement. The electromyographic ratios correlated negatively with sulcus angles. CONCLUSION: Subjects with knee osteoarthritis with patellar malalignment exhibited an imbalance in quadriceps contraction, as confirmed by altered vastus medialis oblique/vastus lateralis ratios associated with larger sulcus angles of the patellofemoral joints. The sulcus angle may be an important contributing factor in causing abnormal patellar tracking in knee osteoarthritis.     

Delayed onset of electromyographic activity of vastus medialis obliquus relative to vastus lateralis in subjects with patellofemoral pain syndrome

OBJECTIVE: To determine whether electromyographic (EMG) onsets of vastus medialis obliquus (VMO) and vastus lateralis (VL) are altered in the presence of patellofemoral pain syndrome (PFPS) during the functional task of stair stepping. DESIGN: Cross-sectional. SETTING: University laboratory. PATIENTS: Thirty-three subjects with PFPS and 33 asymptomatic controls. INTERVENTIONS: Subjects ascended and descended a set of stairs-2 steps, each 20-cm high-at usual stair-stepping pace. EMG readings of VMO and VL taken on middle stair during step up (concentric contraction) and step down (eccentric contraction). MAIN OUTCOME MEASURES: Relative difference in onset of surface EMG activity of VMO compared with VL during a stair-stepping task. EMG onsets were determined by using a computer algorithm and were verified visually. RESULTS: In the PFPS population, the EMG onset of VL occurred before that of VMO in both the step up and step down phases of the stair-stepping task (p <.05). In contrast, no such differences occurred in the onsets of EMG activity of VMO and VL in either phase of the task for the control subjects. CONCLUSION: This finding supports the hypothesized relationship between changes in the timing of activity of the vastimuscles and PFPS. This finding provides theoretical rationale to support physiotherapy treatment commonly used in the management of PFPS.     

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。     

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     

Vastus medialis obliquus and vastus lateralis activity in open and closed kinetic chain exercises in patients with patellofemoral pain syndrome: an electromyographic study

OBJECTIVES: To evaluate the electromyographic activities of vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles in open and closed kinetic chain exercises in subjects with patellofemoral pain syndrome (PFPS). DESIGN: Case-controlled study. SETTING: Rehabilitation science center in a tertiary medical center. PARTICIPANTS: Ten patients with bilateral knee pain diagnosed with PFPS and 10 healthy volunteers. INTERVENTIONS: Subjects performed open kinetic chain exercise on an isokinetic dynamometer and closed kinetic chain exercise by squat-to-stand and stand-to-squat tasks. Surface electromyography was done for the VMO and VL muscles. MAIN OUTCOME MEASURES: VMO/VL ratios were calculated after normalization of muscle activities. RESULTS: The VMO/VL ratios of PFPS subjects were significantly lower than were those of unimpaired subjects during knee isokinetic closed kinetic chain exercises (p = .047). However, there was no statistical difference in VMO/VL ratio between subjects with and without PFPS during closed kinetic chain exercises (p = .623). Maximum VMO/VL ratio was obtained at 60 degrees knee flexion in closed kinetic chain exercise. CONCLUSION: In closed kinetic chain exercises, more selective VMO activation can be obtained at 60 degrees knee flexion. Maximal VMO/VL ratio was observed at this knee flexion angle, and muscle contraction intensity was also greatest.     

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.     

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.