Vastus Medialis Obliquus Research Articles

Differences in age-related fiber atrophy between vastii muscles of active subjects: a multichannel surface EMG study

The aim of the study was to non-invasively determine if vastus lateralis (VL) and vastus medialis obliquus (VM) muscles are equally affected by age-related fiber atrophy. Multichannel surface electromyography was used since it allows to estimate muscle fiber conduction velocity (CV), which has been demonstrated to be related to the size of recruited muscle fibers. Twelve active elderly men (age 69 ± 4 years) and 12 active young men (age 23 ± 2 years) performed isometric knee extension at 30%, 50%, and 70% of maximal voluntary contraction. Electromyographic signals were recorded from VL and VM muscles of the dominant limb using arrays with eight electrodes and CVs were estimated for each contraction. CV estimates showed a different behavior in the two muscles: in VL at 50% and 70% of maximum voluntary contraction they were greater in young than in elderly; whereas such a difference was not observed in VM. This finding suggest that in active elderly VM seems to be less affected by the age-related fibers atrophy than VL. Hence, the common choice of studying VL as a muscle representative of the whole quadriceps could generate misleading findings. Indeed, it seemed that the sarcopenic ageing effects might be heterogeneous within quadriceps muscle.

The Effect of Altering Knee Position and Squat Depth on VMO : VL EMG Ratio During Squat Exercises

Patellofemoral pain syndrome is an extremely common condition, believed to be caused by altered activation of vastus medialis obliquus (VMO), leading to maltracking of the patella. This study aimed to investigate the effect of altering knee movement and squat depth on the ratio of VMO and vastus lateralis (VMO : VL) during squat exercises. Eighteen (7 male and 11 female) healthy, asymptomatic participants performed semi-squat exercises with three squat depths (20°, 50° and 80° of knee flexion) while following three knee movement paths (neutral, varus or valgus). Normalized VMO : VL ratio from linear envelope surface electromyography was analysed. No significant effect was found for gender (p = 0.87), leg dominance (p = 0.99) or knee position (p = 0.44). A significant effect was found for squat depth (p < 0.001) with both the 50° and 80° squats showing increases in VMO : VL ratio (p = 0.031 and p = 0.028), respectively. The VMO : VL ratio was not influenced by gender, leg dominance or knee position in semi-squat exercises. Increases in relative VMO activation did occur in 'deeper' squat depths (50° and 80° knee flexion) compared with the 20° condition. Further research is needed in this area concerning the effects of such exercise modifications on a symptomatic patellofemoral pain syndrome population. Copyright © 2015 John Wiley & Sons, Ltd.

Rehabilitation following first-time patellar dislocation: A randomised controlled trial of purported vastus medialis obliquus muscle versus general quadriceps strengthening exercises

BackgroundWe aimed to define whether distal vastus medialis (VM) muscle strengthening improves functional outcomes compared to general quadriceps muscle strengthening following first-time patellar dislocation (FTPD). MethodsFifty patients post-FTPD were randomised to either a general quadriceps exercise or rehabilitation programme (n=25) or a specific-VM exercise and rehabilitation regime (n=25). The primary outcome was the Lysholm knee score, and secondary outcomes included the Tegner Level of Activity score, the Norwich Patellar Instability (NPI) score, and isometric knee extension strength at various knee flexion ranges of motion. Outcomes were assessed at baseline, six weeks, six months and 12months. ResultsThere were statistically significant differences in functional outcome and activity levels with the Lysholm knee score and Tegner Level of Activity score at 12months in the general quadriceps exercise group compared to the VM group (p=0.05; 95% confidence interval (CI): −14.0 to 0.0/p=0.04; 95% CI: −3.0 to 0.0). This did not reach a clinically important difference. There was no statistically significant difference between the groups for the NPI score and isometric strength at any follow-up interval. The trial experienced substantial participant attrition (52% at 12months). ConclusionsWhilst there was a statistical difference in the Lysholm knee score and Tegner Level of Activity score between general quadriceps and VM exercise groups at 12months, this may not have necessarily been clinically important. This trial highlights that participant recruitment and retention are challenges which should be considered when designing future trials in this population. Level of evidenceTherapeutic study, Level I

Muscle-Activation Onset Times With Shoes and Foot Orthoses in Participants With Chronic Ankle Instability

Participants with chronic ankle instability (CAI) use an altered neuromuscular strategy to shift weight from double-legged to single-legged stance. Shoes and foot orthoses may influence these muscle-activation patterns. To evaluate the influence of shoes and foot orthoses on onset times of lower extremity muscle activity in participants with CAI during the transition from double-legged to single-legged stance. Cross-sectional study. Musculoskeletal laboratory. A total of 15 people (9 men, 6 women; age = 21.8 ± 3.0 years, height = 177.7 ± 9.6 cm, mass = 72.0 ± 14.6 kg) who had CAI and wore foot orthoses were recruited. A transition task from double-legged to single-legged stance was performed with eyes open and with eyes closed. Both limbs were tested in 4 experimental conditions: (1) barefoot (BF), (2) shoes only, (3) shoes with standard foot orthoses, and (4) shoes with custom foot orthoses (SCFO). The onset of activity of 9 lower extremity muscles was recorded using surface electromyography and a single force plate. Based on a full-factorial (condition, region, limb, vision) linear model for repeated measures, we found a condition effect (F(3,91.8) = 9.39, P < .001). Differences among experimental conditions did not depend on limb or vision condition. Based on a 2-way (condition, muscle) linear model within each region (ankle, knee, hip), earlier muscle-activation onset times were observed in the SCFO than in the BF condition for the peroneus longus (P < .001), tibialis anterior (P = .003), vastus medialis obliquus (P = .04), and vastus lateralis (P = .005). Furthermore, the peroneus longus was activated earlier in the shoes-only (P = .02) and shoes-with-standard-foot-orthoses (P = .03) conditions than in the BF condition. No differences were observed for the hip muscles. Earlier onset of muscle activity was most apparent in the SCFO condition for ankle and knee muscles but not for hip muscles during the transition from double-legged to single-legged stance. These findings might help clinicians understand how shoes and foot orthoses can influence neuromuscular control in participants with CAI.

Interventions for treating fractures of the patella in adults

Interventions for treating fractures of the patella in adults

Muscle activation features of the osteoarthritic knee with patellar lateral subluxation

The aim of the study was to compare the muscle activation feature of vastus medialis obliquus (VMO) and vastus lateralis (VL) between the osteoarthritic knee patients with patellar lateral subluxation (Group 1B) and without patellar lateral subluxation (Group 1A). Isokinetic muscle strength of the knee extensor was evaluated using a CYBEX NORM dynamometer with angular velocities of 80, 120 and 240 degrees/second (°/sec) respectively, contraction activities of VMO and VL muscle were recorded with synchronized surface electromyography (sEMG). Age-matched healthy subjects were recruited and served as control group (Group 2). The VMO/VL ratio of EMG between Group 1A, Group 1B and Group 2 were compared. The peak torque in Group A was 40.7 ± 12.9, in Group B was 39.6 ± 12.9 and in Group C was 60.2 ± 9.5 respectively at 80°/sec angular velocity (p < 0.01). There were no significant difference between Group 1A and Group 1B in the three trial of tested velocities (p > 0.01). The sEMG ratios of VMO/VL of Group 1B calculated at angular velocities of 80/sec was 0.769 ± 0.15, 120°/sec was 0.818 ± 0.22 and 240°/ sec was 0.850 ± 0.22, all those were lower than Group 1A and Group 2 (p<0.01). Musculature imbalance of VMO and VL may explain the different muscle activation pattern in osteoarthritic knee patients with and without patellar lateral subluxation.

Dynamic Valgus Instability of the Knee due to Chronic Medical Collateral Ligament Laxity as a Cause of Recurrent Patella Dislocation

Recurrent patella dislocation can be caused by bony abnormalities, such as patella alta, increased tibial tubercle lateralization, trochlea dysplasia, excessive femoral neck anteversion and external tibial torsion. It can also be caused by soft tissue abnormalities such as a ruptured medial patellofemoral ligament (MPFL) or a weak vastus medialis obliquus. It has been reported in the literature that acute lateral dislocation of the patella can be associated with proximal injury to the medial collateral ligament (MCL). This article reports the case of a 26-year-old male pro footballer who had recurrent patella dislocation related to previous injury to his MPFL and worsened by dynamic valgus knee instability due to chronic MCL insufficiency.

Imaging of the patellofemoral pain syndrome

Anterior knee pain, diagnosed as patellofemoral pain syndrome (PFPS), is one of the most common musculoskeletal disorders. It is of high socioeconomic relevance as it occurs most frequently in young and active patients. The rate is around 15–33 % in an active adult population and 21–45 % in adolescents. Females are twice at greater risk for PFPS. Despite of its high incidence and abundance of symptoms, its pathogenesis is still not well understood. There are many possible causes for PFPS: hip muscle weakness, vastus medialis obliquus and vastus lateralis imbalance, increased hamstring tightness, iliotibial tract tightness, patellar maltracking, foot eversion. Etiologic factors were classified as local, distal, and proximal. Aim of this literature review is to overview reasons regarding the underlying pathology of PFPS and value of different radiological imaging modalities.

Quadriceps Muscle Mechanical Simulator for Training of Vastus Medialis Obliquus and Vastus Lateralis Obliquus Mechanical Properties

Objectives:In classical anatomy quadriceps muscle has four heads. Clinical studies have demostrated 6 heads of this muscle. These heads were demostrated seperately not only by their functional properties,but also by innervation and kinesiological properties. In our previous study we have developed and demostrated electrophysiological properties of vastus medialis obliquus by an electronic patient simulator. The purpose of this study is to develop a mechanical simulator which can be used to demostrate mechanical properties of 6 heads of quadriceps muscle and the screw home mechanism.Methods:Quadriceps femoris muscle has 6 heads: rectus femoris, vastus intermedius, vastus medialis obliquus, vastus medialis longus, vastus lateralis obliquus and vastus lateralis longus. The fundamental mechanical properties of each head is seperated by insersio and angle of pull. Main design principle was to demostrate all heads with insersio and angle of pull properties. Second design principle was to demostrate the screw-home mechanism which is the result of difference in articular surfaces of medial and lateral of condyles of femur.Results:Final design of the simulator consists of three planes for demostration of angle of pull and pulling forces (patellar plane, proximal and distal planes) of each heads. On each plane channels were graved as origo and insersio for demostration of angle of pull. Distal plane was movable for demostration of pulling forces in different angels of knee flexion and extention. Also proximal plane was adjustable to demostrate different sitting and standing positions. Srew home mechanism was demostrated by specially designed hingle mechanism. Left and right side hingle mechanisms have different radii as femoral condyles and this difference can cause rotation in terminal extension as in the screw home mechanism.Conclusion:Vastus medialis obliquus, vastus lateralis obliquus and screw-home mechanism have clinical significance. We were not able to find any study which deals with training of screw home mechanism and vastus medialis obliqus and wastus lateralis obliquus muscles in the literature. The purpose of this study was to develop a simulator which can demostrate mechanical properties of vastus medialis obliquus and vastus lateralis muscles and screw home mechanism. As a result a traning simulator with stated properties was developed. In this simulator force measurement is acheived with analog dynamometers and future studies may focus on improvement of this simulator with digital force measurement.

Foot orthoses induce immediate changes in lower limb neuromotor control of gait in people with patellofemoral joint osteoarthritis: a pilot study

Foot orthoses induce immediate changes in lower limb neuromotor control of gait in people with patellofemoral joint osteoarthritis: a pilot study

Anatomical study of the medial patello-femoral ligament: landmarks for its surgical reconstruction

The aim of this dissection study was to describe the anatomical insertions of the medial patello-femoral ligament (MPFL), and to assess its relationship with surrounding structures to improve its surgical reconstruction. Twelve knees (7 cadavers) were included for the study. Measurements and general features of the MPFL were assessed: lengths, widths and insertions. The MPFL was found in all knees, presenting a triangular shape, and extending from the medial part of the patella to its femoral insertion (its length was of 59±6.6mm), distal to the adductor tubercle. The mean femoral insertion of the MPFL was 7.2±2.7mm proximal and 7.4±4.0mm posterior to the medial femoral epicondyle (MFE). It was also at a mean 11±2.8mm distal and 1.3±2.1mm posterior to the adductor tubercle, and 22±6.4mm anterior to the posterior condyle. We did not find any double-bundle organization on the patellar insertion. The width of the MPFL was 8.8±2.9mm at the femoral insertion, 27±5.9mm at the patellar insertion, and 12±3.1mm in the middle of the MPFL. The vastus medialis obliquus was found to be inserted on the superior part of the MPFL. The adductor tubercle appeared to be a better landmark than the MFE for the femoral tunnel positioning during surgical reconstructions of the MPFL because it was easier to identify and its relationship with the femoral insertion of the MPFL was constant (10mm below).

Spinal Reflex Arc Excitability Corresponding to the Vastus Medialis Obliquus and Vastus Medialis Longus Muscles

[Purpose] The gross morphology of the vastus medialis (VM) muscle has been thoroughly described. However, there is insufficient evidence of physiological differentiation between the VM obliquus (VMO) and VM longus (VML). To elucidate spinal reflex arc excitability in two divisions of the VM, we compared H-reflexes and T-waves in VMO and VML. [Subjects] Twenty-three healthy male volunteers participated in this study. [Methods] The H-reflex was evoked from the VMO and VML by electrical stimulation of the femoral nerve during knee extension at 10% maximal voluntary isometric contraction. Also, the patellar tendon was tapped by an examiner using an electrical tendon hammer, and a component of the compound muscle action potential (T-wave) was recorded. [Results] The configurations of the H-reflex and T-wave were sharp and slow in VMO and VML, respectively. No significant differences in the amplitudes of the H-reflexes and T-waves were observed between VMO and VML. The durations of VML H-reflexes and T-waves were significantly longer than those in VMO. [Conclusion] Spinal reflex arc excitability corresponding to VMO and VML was similar. However, the configurations and durations of the H-reflex and T-wave were differentiated with electromyography. On the basis of these findings, we suggest that VMO and VML are electrophysiologically distinct entities.

Vastus Medialis Obliquus Muscle Morphology in Primary and Recurrent Lateral Patellar Instability

The morphology of the vastus medialis obliquus (VMO) muscle in the anatomical setting of an unstable patella has not been described. Therefore, the purpose of this study was to investigate the morphological parameters of the VMO muscle that delineate its importance in the maintenance of patellofemoral joint stability. Eighty-two consecutive subjects were prospectively enrolled in this study. The groups were composed of thirty patients with an acute primary patellar dislocation, thirty patients with recurrent patellar dislocation, and twenty-two controls. Groups were adjusted according to sex, age, body mass index, and physical activity. Magnetic resonance imaging was used to measure the VMO cross-sectional area, muscle-fiber angulation, and the craniocaudal extent of the muscle in relation to the patella. No significant difference was found with respect to all measured VMO parameters between primary dislocation, recurrent dislocation, and control subjects with a trend noted for only the VMO cross-sectional area and the VMO muscle-fiber angulation. This finding is notable in that atrophy of the VMO has often been suggested to play an important role in the pathophysiology of an unstable patellofemoral joint.

Clinical and Functional Outcomes following Primary Repair versus Reconstruction of the Medial Patellofemoral Ligament for Recurrent Patellar Instability

Background. The purpose of this study was to compare outcomes of medial patellofemoral ligament (MPFL) repair or reconstruction. Methods. Fourteen knees that underwent MPFL repair and nine (F5, M4) knees that underwent reconstruction at our institution were evaluated for objective and subjective outcomes. The mean age at operation was 20.1 years for repair and 19.8 years for reconstruction. All patients had a minimum of 2 years of follow-up (range: 24–75 months). Patient subjective outcomes were obtained using the International Knee Documentation Committee (IKDC) and Kujala patellofemoral subjective evaluations, as well as Visual Analog (VAS) and Tegner Activity Scales. Bilateral isometric quadriceps strength and vastus medialis obliquus (VMO) and vastus lateralis (VL) surface EMG were measured during maximal isometric quadriceps contractions at 30° and 60° of flexion. Results. There were no redislocations in either group. There was no difference in IKDC (P = 0.16), Kujala (P = 0.43), Tegner (P = 0.12), or VAS (P = 0.05) scores at follow-up. There were no differences between repair and reconstruction in torque generation of the involved side at 30° (P = 0.96) and 60° (P = 0.99). In addition, there was no side to side difference in torque generation or surface EMG activation of VL or VMO. Conclusions. There were minimal differences found between patients undergoing MPFL repair and MPFL reconstruction for the objective and subjective evaluations in this study.

Shear Wave Elastography Properties of Vastus Lateralis and Vastus Medialis Obliquus Muscles in Normal Subjects and Female Patients With Patellofemoral Pain Syndrome

Shear Wave Elastography Properties of Vastus Lateralis and Vastus Medialis Obliquus Muscles in Normal Subjects and Female Patients With Patellofemoral Pain Syndrome

Does Quadriceps Atrophy Exist in Individuals With Patellofemoral Pain? A Systematic Literature Review With Meta-analysis

Systematic literature review. To investigate whether quadriceps atrophy is present in the affected limb of individuals with patellofemoral pain (PFP). PFP is a common condition. Atrophy of the quadriceps femoris, in particular the vastus medialis obliquus, is often assumed to be present by clinicians, and its resolution may underpin the reported effectiveness of quadriceps strengthening intervention in PFP rehabilitation. A systematic search of the literature was conducted to identify studies that measured the size of the quadriceps in individuals with PFP. Meta-analyses were performed to determine whether quadriceps size in limbs with PFP differed from that in comparison limbs. Separate meta-analyses were performed for quadriceps size measured as girth and quadriceps size measured with imaging (thickness, cross-sectional area, and volume). Ten studies were included in this review. The meta-analysis of girth measurements (3 studies) found no atrophy in limbs with PFP (P = .638). The meta-analyses for imaging techniques (thickness, cross-sectional area, or volume measurements) showed atrophy in the limb with PFP compared to both the asymptomatic limb (3 studies) (P = .036) and limbs from a comparison group (3 studies) (P = .001). The single study that compared the vastus medialis obliquus and vastus lateralis in individuals with PFP found atrophy of both the vastus medialis obliquus and vastus lateralis but no significant difference in the amount of atrophy between them (P = .179). Quadriceps muscle atrophy was shown to be present in PFP when analyzed by imaging, but not by girth measures. Insufficient data were available to determine if there was greater atrophy of the vastus medialis obliquus than the vastus lateralis. These findings support the rationale for use of quadriceps strengthening as part of a rehabilitation program for PFP.

Clinical and Electromyographic Results of Proximal and Distal Realignment Procedures in Young Patients With Recurrent Patellar Dislocations

Background: Until now, no study has been published about the electromyographic changes in the extensor apparatus after the Green procedure for proximal realignment in young patients with recurrent patellar dislocations. This electromyographic study was performed to analyze imbalances between the vastus medialis and vastus lateralis muscles after different patellar realignment procedures. Hypothesis: Surgical proximal realignment leads to electromyographic changes in the extensor apparatus of the knee and to imbalances between the vastus medialis and vastus lateralis muscles. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 28 knees of 25 patients, with a mean age of 15 years, were treated operatively for recurrent patellar dislocations. The mean follow-up was 6.3 years. Depending on the type of surgical intervention, the patients were assigned to 3 different groups: the patients of group 1 underwent only the Green vastus medialis obliquus (VMO) advancement, group 2 was treated with a combination of the Green proximal and the Roux-Goldthwait distal realignment, and group 3 was treated with a combination of the Green proximal realignment and an additional tubercle transfer. All patients underwent clinical, radiological, and electromyographic examinations. The muscle activities of a healthy control group without patellar dislocations were used for comparison. Results: A combination of the Green procedure and tubercle transfer led to significantly better clinical results and a lower number of redislocations (P < .05) compared with patients who underwent only the Green proximal realignment. While ascending or descending stairs, the ratio between the electromyographic activities of the vastus medialis and vastus lateralis muscles in groups 1 and 2 was significantly smaller compared with the control group (P < .02). Only the electromyograms of group 3 revealed a balanced extensor apparatus during loading with comparable activities of the vastus medialis and vastus lateralis muscles and no significant difference to the control group (P = .37). Conclusion: Our electromyographic investigations showed the importance of the vastus medialis in the pathogenesis of malalignment of the extensor mechanism. The Green VMO advancement without tibial tubercle transfer is not able to balance the activities of the vastus medialis and vastus lateralis muscles and cannot be recommended for further use.

Retracted: Muscles within muscles: a tensiomyographic and histochemical analysis of the normal human vastus medialis longus and vastus medialis obliquus muscles

The aim of this study was to show the connection between structure (anatomical and histochemical) and function (muscle contraction properties) of vastus medialis obliquus (VMO) and vastus medialis longus (VML). The non-invasive tensiomyography (TMG) method was used to determine the contractile properties (contraction time; T(c)) of VML and VMO muscle, as a reflection of the ratio between the slow and fast fibers in two groups of nine young men. VML and VMO significantly (P < 0.01) differ in the proportion of type 1 (59.6: 44%) and type 2b (6.3: 15%) fibers. The VML muscle is almost entirely composed of type 1 and type 2a fibers. In many samples of this muscle no type 2b fibers were found. The proportion of slow-twitch type 1 fibers is nearly twice as high as the proportion of fast-twitch type 2a fibers. These observations indicate that VML is a slower and more fatigue-resistant muscle than VMO muscle. These characteristics correspond to the different functions of the VML, which is an extensor of the knee, and to the VMO, which maintains the stable position of the patella in the femoral groove. Our results obtained by TMG provided additional evidence that muscle fibers within the segments of VM muscle were not homogenous with regard to their contractile properties, thereby confirming the histochemical results. T(c) can be attributed to the higher percentage of slow-twitch fibers - type 1. The statistically shorter T(c) (P ≤ 0.001) of VMO (22.8 ± 4.0 ms) compared with VML (26.7 ± 4.0 ms) in our study is consistent with previously found differences in histochemical, morphological and electrophysiological data. In conclusion, the results of this study provide evidence that the VML and VMO muscles are not only anatomically and histochemically different muscles, but also functionally different biological structures.

Midterm Results of Comprehensive Surgical Reconstruction Including Sulcus-Deepening Trochleoplasty in Recurrent Patellar Dislocations With High-Grade Trochlear Dysplasia

Background: Trochlear dysplasia is one of the most consistent anatomic factors that can lead to recurrent patellar dislocations. Various trochleoplasty procedures have been described to treat patellar dislocations in high-grade dysplasia by creating a new congruent trochlea. Purpose: To present the midterm efficacy and outcome of the sulcus-deepening trochleoplasty procedure in patients with recurrent patellar dislocations due to high-grade trochlear dysplasia. The clinical evaluation results, the amount of radiological correction, and the prevalence of arthritis were recorded. Study Design: Case series; Level of evidence, 4. Methods: A total of 27 skeletally mature patients (31 knees) with recurrent patellar dislocations due to high-grade trochlear dysplasia without any previous surgery were retrospectively included from September 1993 to September 2006. All patients underwent sulcus-deepening trochleoplasty combined with a bony and/or soft tissue procedure according to concomitant etiological factors to patellar dislocations: medial patellofemoral ligament reconstruction (16.1%), vastus medialis obliquus plasty (83.8%), tibial tuberosity distalization (51.6%), tibial tuberosity medialization (67.7%), and lateral retinaculum release (67.6%). Mean follow-up was 7 years (range, 2-9 years). Results: The mean sulcus angle decreased significantly (P < .01) from 152° ± 16° preoperatively to 141° ± 9° postoperatively, tibial tuberosity–trochlear groove distance decreased significantly (P < .001) from 19 ± 4 mm to 12 ± 5 mm, and patellar tilt decreased significantly (P < .001) from 37° ± 7° to 15° ± 8°. No recurrence was observed, and there was no case of stiffness. Apprehension signs remained positive in 19.3% of the cases, patellar tracking was normal in all cases, and the lateral patellar glide test finding was negative in 96.8%. The mean preoperative International Knee Documentation Committee (IKDC) score was 51 (range, 25-80), and the mean postoperative IKDC score was 82 (range, 40-100) (P < .001), while the mean Kujala score improved from a preoperative 59 (range, 28-81) to 87 (range, 49-100) postoperatively (P < .001). There was no radiographic evidence of patellofemoral arthritis at the latest follow-up. Conclusion: Sulcus-deepening trochleoplasty is a valid option for the primary surgical treatment of carefully selected patients with recurrent patellar dislocations with high-grade trochlear dysplasia type B and D. Concomitant etiological factors must be cautiously corrected in an associated procedure. Midterm follow-up showed satisfactory restoration of patellar stability and improvement of knee scores with no complication of subsequent arthritis.

Use of Motor Imagery Enhances Vastus Medialis Obliquus Muscle Recruitment Amplitudes During Closed Kinetic Chain Squat Exercises

ABSTRACT: The purpose of this study was to examine whether the use of motor imagery during the performance of a simple exercise results in increased recruitment in the actively contracting muscles. Sixteen female participants were randomly assigned to an imagery group (n = 8) or a control group (n = 8). Participants performed 3 repetitions of 2 exercises (squats and plies). Although there were no significant differences in vastus medialis obliquus (VMO) muscle activation (electromyography [EMG]) amplitudes between the imagery and control groups, there was a clear trend toward higher EMG amplitudes in the imagery group compared with the control group for the left VMO, which was attributed to the imagery group partici-pants directing their imagery to the left limb. For both groups, the squat exercise elicited sig-nificantly higher EMG amplitudes than the plie exercise in both the concentric and eccentric phases of the movement. Although the expected significant differences in EMG amplitudes between the imagery and control groups were not observed, the results of this study suggest that motor imagery is a simple and cost-effective technique that may result in more effective training/rehabilitation practices.