EMG Analysis of the Vastus Medialis/Vastus Lateralis Muscles Utilizing the Unloaded Narrow- and Wide-Stance Squats

1998 ◽  
Vol 7 (4) ◽  
pp. 236-247 ◽  
Author(s):  
Ricky Anderson ◽  
Carol Courtney ◽  
Eli Carmeli
Keyword(s):  
Knee Flexion ◽  
Healthy Subjects ◽  
Vastus Lateralis ◽  
Emg Activity ◽  
Vastus Medialis ◽  
Significant Difference ◽  
The Difference

The purpose of this study was to see if vastus medialis oblique/vastus lateralis (VMO:VL) ratios could be increased by widening the squat stance and if the VMO activity increases with deeper ranges of knee flexion. Fifteen healthy subjects performed unloaded narrow and wide stance squats through three ranges of knee flexion: 30°, 60°, and 90°. The two squat stances were compared using a 2 × 3 ANOVA to see if the wide-stance squat had any significant difference in EMG activity for VMO: VL ratios compared to the narrow-stance squat. The difference in EMG activity of the VMO between the various angles for both squat stances was also compared. The ANOVA revealed no significant differences between the squat stances for VMO:VL ratios but did show the VMO:VL ratios to be significantly higher with increasing knee flexion angles. These findings suggest that the VMO is active throughout the 90° range and that increasing knee flexion angles can elicit greater activity of the VMO relative to the VL.

Evaluating electromyographic activity of vastus medialis obliqus, vastus lateralis, and hamstrings in women with patellofemoral pain syndrome

2020 ◽  
Author(s):  
Mahsa Mazaheri ◽  
Alireza Motealleh ◽  
sobhan sobhani ◽  
amin kordi yoosefinejad
Keyword(s):  
Healthy Subjects ◽  
Vastus Lateralis ◽  
Pain Syndrome ◽  
Patellofemoral Pain Syndrome ◽  
Patellofemoral Pain ◽  
Emg Activity ◽  
Tibial Rotation ◽  
Electromyographic Activity ◽  
Vastus Medialis ◽  
Significant Difference

Abstract Background: Temporal difference in activation of medial-lateral hamstrings could lead to external tibial rotation. It was assumed that patients with patellofemoral pain syndrome (PFPS) exhibit altered medial-lateral hamstrings muscular pattern during functional tasks. Objectives: The aim of this study was to compare the electromyography (EMG) activity of quadriceps and hamstrings in patients with PFPS and healthy subjects during stair descending. Design: cross sectional comparative study Setting: Motion analysis Lab, Rehabilitation research center, Shiraz University of Medical Sciences Participants: 24 women with PFPS and 24 healthy subjects, aged 18-40 years recruited through convenience sampling method participated in this study. Interventions: The EMG activity of vastus medialis obliqus (VMO), vastus lateralis (VL), medial (MH) and lateral hamstrings (LH) recorded during stair descending. Main outcome measures: Onset latency and intensity of muscle activity measured relative to the moment of foot contact. Results: There were statistically significant difference in onset of hamstrings heads (LH-MH) between groups (p=0.014). The BF activated before ST in PFPS group. Normalized muscular activity was significantly reduced for VMO (p=0.002), VL (p=.045), and LH (p=0.019) in PFPS patients. Conclusions: Difference in temporal activation patterns of BF and ST may result in lack of rotational knee stabilization and lead to increased patellofemoral joint pressure. Earlier activation of LH rotates tibia externally, and hence, produced lateral patellar tracking.

The Association of Obesity With Quadriceps Activation During Sit-to-Stand

2020 ◽  
Vol 100 (12) ◽  
pp. 2134-2143
Author(s):  
Lance M Bollinger ◽  
Amanda L Ransom
Keyword(s):  
Vastus Lateralis ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Knee Extensors ◽  
Emg Activity ◽  
Vastus Medialis ◽  
Trunk Flexion ◽  
Maximal Voluntary Isometric Contraction ◽  
Sit To Stand ◽  
The Mean

Abstract Objective Obesity reduces voluntary recruitment of quadriceps during single-joint exercises, but the effects of obesity on quadriceps femoris muscle activation during dynamic daily living tasks, such as sit-to-stand (STS), are largely unknown. The purpose of this study was to determine how obesity affects quadriceps muscle recruitment during STS. Methods In this cross-sectional study, 10 women who were lean and 17 women who were obese completed STS from a chair with arms crossed over the chest. Three-dimensional motion analysis was used to define 3 distinct phases (I–III) of the STS cycle. The electromyographic (EMG) activity of the vastus medialis, vastus lateralis, and semitendinosus was measured. Results STS duration was greater (3.02 [SD = 0.75] seconds vs 1.67 [SD = 0.28] seconds) and peak trunk flexion angle was lower (28.9 degrees [SD = 10.4 degrees] vs 35.8 degrees [SD = 10.1 degrees]) in the women who were obese than in the women who were lean. The mean EMG activity of the knee extensors increased from phase I to phase II in both groups; however, the mean EMG activities of both the vastus medialis (32.1% [SD = 16.6%] vs 47.3% [SD = 19.6%] maximal voluntary isometric contraction) and the vastus lateralis (31.8% [SD = 19.4%] vs 47.5% [SD = 19.6%] maximal voluntary isometric contraction) were significantly lower during phase II in the women who were obese. The mean EMG activity of the semitendinosus increased throughout STS but was not significantly different between the 2 groups. Coactivation of the semitendinosus and knee extensors tended to be greater in the women who were obese but failed to reach statistical significance. Conclusions Knee extensor EMG amplitude was reduced in women who were obese during STS, despite reduced trunk flexion. Impact Reduced knee extensor recruitment during STS in obesity may redistribute forces needed to complete this task to other joints. Functional movement training may help improve knee extensor recruitment during STS in people who are obese. Lay Summary People with obesity often have low quadriceps muscle strength and impaired mobility during daily activities. This study shows that women who are obese have lower voluntary recruitment of quadriceps when rising from a chair than women who are lean do, which could increase workload on hip or ankle muscles during this important daily task. Quadriceps strengthening exercises might improve the ability to rise from sitting to standing.

scholarly journals The impact of anterior cruciate ligament deficiency and reconstruction on bilateral thigh muscle activity during stair descent

2001 ◽  
Vol 57 (2) ◽  
pp. 16-21 ◽  
Author(s):  
A. St Clair Gibson ◽  
M. I. Lambert ◽  
C. L. Vaughan ◽  
M. Lowery ◽  
M. J. O'Malley ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Vastus Lateralis ◽  
Cruciate Ligament ◽  
Thigh Muscle ◽  
Emg Activity ◽  
Vastus Medialis ◽  
Stair Descent ◽  
Step Down ◽  
Anterior Cruciate ◽  
Acl Deficient

Aim: To assess electromyographic (EMG) gait pattern changes during stair descent in subjects with chronic anterior cruciate ligament (ACL) deficiency, and in subjects after ACL reconstruction.Methods: Thirteen ACL deficient subjects (ACLdef), 8 ACL reconstructed subjects (ACLrec), and 10 controls (CON) participated in the study. All subjects were assessed for functional and lean thigh volume (LTV) differences in the injured and uninjured limb. All subjects then stepped off a bench with EMG electrodes on the vastus medialis, vastus lateralis and hamstrings muscles of both limbs.Results: Step down activity caused similar EMG responses in the injured and supporting limb in the ACLdef group compared to that in the control group. In contrast, in the ACLrec group, the onset of EMG activity occurred earlier during the step down activity in the vastus medialis and vastus lateralis of the supporting limb. There was significantly greater EMG activity in the vastus lateralis and hamstring muscles of the supporting limb (p < 0.05) in the ACLrec group compared to ACLdef and control groups. The changes in EMG activity did not appear to be related to differences in LTV, since greater LTV deficits were present in the ACLdef compared to the ACLrec group (p < 0.01).Conclusions: In ACL reconstructed subjects, changes in muscle recruitment patterns in the supporting limb during step down activity have been identified. This altered activity pattern was not present in the supporting limb of ACL deficient subjects

scholarly journals Frontal Alpha Complexity of Different Severity Depression Patients

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Lulu Zhao ◽  
Licai Yang ◽  
Baimin Li ◽  
Zhonghua Su ◽  
Chengyu Liu
Keyword(s):  
Neuronal Activity ◽  
Healthy Subjects ◽  
Sample Entropy ◽  
Rank Test ◽  
Mild Depression ◽  
Healthy Group ◽  
Significant Difference ◽  
Entropy Measures ◽  
The Difference ◽  
State Group

Depression is a leading cause of disability worldwide, and objective biomarkers are required for future computer-aided diagnosis. This study aims to assess the variation of frontal alpha complexity among different severity depression patients and healthy subjects, therefore to explore the depressed neuronal activity and to suggest valid biomarkers. 69 depression patients (divided into three groups according to the disease severity) and 14 healthy subjects were employed to collect 3-channel resting Electroencephalogram signals. Sample entropy and Lempel–Ziv complexity methods were employed to evaluate the Electroencephalogram complexity among different severity depression groups and healthy group. Kruskal–Wallis rank test and group t-test were performed to test the difference significance among four groups and between each two groups separately. All indexes values show that depression patients have significantly increased complexity compared to healthy subjects, and furthermore, the complexity keeps increasing as the depression deepens. Sample entropy measures exhibit superiority in distinguishing mild depression from healthy group with significant difference even between nondepressive state group and healthy group. The results confirm the altered neuronal activity influenced by depression severity and suggest sample entropy and Lempel–Ziv complexity as promising biomarkers in future depression evaluation and diagnosis.

scholarly journals Impact of the Allergic Asthma on Foot Health-Related Quality of Life and Depression: A Novel Case-Control Research

Medicina ◽  
2019 ◽  
Vol 55 (5) ◽  
pp. 124
Author(s):  
Daniel López-López ◽  
Roi Painceira-Villar ◽  
Vanesa García-Paz ◽  
Ricardo Becerro-de-Bengoa-Vallejo ◽  
Marta Elena Losa-Iglesias ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Allergic Asthma ◽  
Healthy Subjects ◽  
Total Sample ◽  
Foot Health ◽  
Significant Difference ◽  
Control Research ◽  
Health Related ◽  
The Difference

Background: Asthma may be considered as a non-communicable condition associated with higher bronchial responsiveness that may impair quality of life (QoL). Purpose: The research aim was to compare scores of depression, as well as general and foot health-related QoL, in patients who suffered from asthma with respect to healthy subjects. Methods: A total sample of 152 subjects, median age of 37.00 ± 16.00 years, were recruited from a respiratory and allergy department of a hospital and divided into patients with asthma (n = 76) and healthy subjects (n = 76). The scores of the Spanish foot health status questionnaire (SFHSQ) domains as well as the Spanish Beck’s Depression Inventory (BDI) scores and categories were collected. Results: The only statistically significant difference (p < 0.05) was shown for the difference of the FHSQ footwear domain establishing that patients who suffered from asthma presented a worse QoL related to foot health for footwear (lower FHSQ scores) compared to healthy matched-paired participants (higher FHSQ scores). Regarding the rest of the outcome measurements, there were no statistically significant differences (p > 0.05) for the other FHSQ domains scores as well as the BDI scores and categories. Conclusions: Patients with allergic asthma presented impairment of the QoL related to foot health for footwear, which seemed to be linked to the presence of asthma.

EMG activity of vastus medialis and vastus lateralis with patellar instability: a systematic review

2008 ◽  
Vol 13 (6) ◽  
pp. 405-414 ◽  
Author(s):  
Toby O. Smith ◽  
John Dixon ◽  
Damien Bowyer ◽  
Leigh Davies ◽  
Simon T Donell
Keyword(s):  
Systematic Review ◽  
Patellar Instability ◽  
Vastus Lateralis ◽  
Emg Activity ◽  
Vastus Medialis

Monitor-Position in Laparoscopic Surgery

2002 ◽  
Vol 46 (16) ◽  
pp. 1506-1510 ◽  
Author(s):  
U. Matern ◽  
K. Kehl ◽  
C. Giebmeyer ◽  
M. Faist
Keyword(s):  
Laparoscopic Surgery ◽  
Task Performance ◽  
Head Movements ◽  
Emg Activity ◽  
Single Session ◽  
Laparoscopic Suturing ◽  
Significant Difference ◽  
The Difference ◽  
The Right ◽  
And Task

One of the key problems in laparoscopy is the correct positioning of the monitor. In this study we tested task performance and muscle-strain of subjects in relation to monitor-position during laparoscopic surgery. 18 subjects simulated laparoscopic suturing. This was repeated in three monitor positions (15 minutes each) frontal at eye level (A), frontal in height of the operating field (B) and 45° to the right side at eye level (C). No head movements were allowed during a single session. In a fourth measurement the subjects were allowed to move the head and to look at any monitor. After the test they were asked for their preferred monitor position. During all tests the electromyographic (EMG) activity of six main neck muscles was recorded and the number of pearls was counted. The EMG activity was significantly (p<0.05) lower for position A compared to position B or C. No significant difference was found between the positions B and C. The number of threaded pearls as an indicator for task performance was highest for position B. The difference was statistically significant compared to position C but not between positions A and C or A and B. Asked for the preferred monitor position 9 subjects chose two monitors in the frontal positions A and B. No subject preferred the monitor at the side (C). Regarding EMG data the monitor positioned frontal at eye level is preferable. Reflecting personal preferences of subjects and task performance it should be of advantage to place two monitors for the surgeon: one in position A for lowest neck strain, and the other one in position B for difficult tasks with optimal task performance. The monitor position at the side is not advisable.

Hip Adduction Does not Affect VMO EMG Amplitude or VMO:VL Ratios during a Dynamic Squat Exercise

2006 ◽  
Vol 15 (3) ◽  
pp. 195-205 ◽  
Author(s):  
Michelle Boling ◽  
Darin Padua ◽  
J. Troy Blackburn ◽  
Meredith Petschauer ◽  
Christopher Hirth
Keyword(s):  
Outcome Measures ◽  
Knee Flexion ◽  
Healthy Subjects ◽  
Vastus Lateralis ◽  
Test Session ◽  
Surface Emg ◽  
Knee Extension ◽  
Emg Amplitude ◽  
Squat Exercise ◽  
History Of

Context:Clinicians commonly attempt to facilitate vastus medialis oblique (VMO) activity by instructing patients to squeeze a ball between their knees during squatting exercises.Objective:To determine whether VMO activation amplitude and the VMO to vastus lateralis (VL) activation ratio (VMO:VL) were altered when performing active hip adduction during a dynamic squat exercise.Design:Single test session.Participants:Fifteen healthy subjects, with no history of knee pain, volunteered for this study.Intervention:Surface EMG of the VMO, VL, and hip adductor (ADD) muscles were recorded while subjects performed 10 consecutive squats against their body weight through a range of 0° to 90° of knee flexion. Subjects performed the squat exercises during two different conditions: (1) active hip adduction and (2) no hip adduction.Main Outcome Measures:Average VMO EMG amplitude and VMO:VL ratio were determined during the knee flexion (0° to 90°) and knee extension (90° to 0°) phases of the squat exercise.Results:Active hip adduction did not significantly change VMO amplitude or VMO:VL ratio during the knee flexion or knee extension phases of the dynamic squat exercise.Conclusions:Based on these results, we conclude that VMO amplitude and the VMO: VL ratio are not influenced by performing active hip adduction during a dynamic squat exercise in healthy subjects.

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