Vastus Lateralis and Vastus Medialis Obliquus Activity during a Straight-Leg Raise and Knee Extension with Lateral Hip Rotation

2002 ◽  
Vol 11 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Nicole M. Livecchi ◽  
Charles W. Armstrong ◽  
Mitchell L. Cordova ◽  
Mark A. Merrick ◽  
James M. Rankin
Keyword(s):  
Repeated Measures ◽  
Outcome Measure ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Emg Activity ◽  
Neutral Position ◽  
Vastus Medialis ◽  
Vastus Medialis Obliquus ◽  
Main Outcome Measure ◽  
Straight Leg Raise

Objective:To compare average electromyogram (EMG) activity of the vastus medialis obliquus (VMO) and vastus lateralis (VL) during straight-leg raise (SLR) and knee extension (KE) with the hip in neutral and lateral rotation.Design:1 × 4 factorial repeated-measures.Setting:Laboratory.Participants:13 male college students.Intervention:SLR with hip flexed at 40°, in neutral position, and maximally laterally rotated and KE with hip in neutral and maximally laterally rotated.Main Outcome Measure:Average EMG activity during each of the 4 conditions, normalized against peak muscle activity during that trial.Results:No differences were observed between exercises in VMO activity (F3,36= 0.646,P> .05), VL activity (F3,36= 1.08,P> .05), or VMO:VL ratio (F3,36= 0.598,P> .05).Conclusions:Electrical activity of the VMO or VL and VMO:VL ratio do not change with hip position or exercise.

The Effect of Pelvic Position on Popliteal Angle Achieved During 90:90 Hamstring-Length Test

2013 ◽  
Vol 22 (4) ◽  
pp. 254-256 ◽  
Author(s):  
Lee Herrington
Keyword(s):  
Repeated Measures ◽  
Human Performance ◽  
Outcome Measure ◽  
Muscle Length ◽  
Knee Extension ◽  
Hamstring Muscle ◽  
Indirect Measure ◽  
Main Outcome Measure ◽  
Starting Position ◽  
Pelvic Position

Context:Hamstring muscle length is commonly measured because of its perceived relationship to injury of both the hamstrings themselves and the pelvis and lumbar spine. The popliteal (knee-extension) angle measured from the starting position hip and knee at 90° is a commonly used indirect measure of hamstring muscle length. When this measure has been undertaken in the literature previously, little attention was paid to the position of the pelvis, which may significantly influence measurements taken.Design:Repeated-measures.Setting:University human performance laboratory.Participants:60 healthy physically active males (mean age 20.1 ± 1.8 y, range 18–24 y).Intervention:The 2 extremes of pelvic position (anterior and posterior).Main Outcome Measure:Popliteal angle (with maximal knee extension) was measured in 2 positions, 1 of full anterior and 1 of full posterior pelvic tilt.Results:The mean difference in popliteal angle between anterior to posterior pelvic positions was 13.4° ± 9° (range 0–26°); this was statistically significant (P = .0001).Conclusion:The findings of the study indicate that pelvic position has a significant effect on popliteal angle and therefore should be taken into account when measuring hamstring muscle length.

The Effects of Ankle Position on Torque and Muscle Activity of the Knee Extensor During Maximal Isometric Contraction

2020 ◽  
Vol 29 (1) ◽  
pp. 37-42
Author(s):  
Dae-Hyun Kim ◽  
Jin-Hee Lee ◽  
Seul-Min Yu ◽  
Chang-Man An
Keyword(s):  
Isometric Contraction ◽  
Vastus Lateralis ◽  
Plantar Flexion ◽  
Isometric Exercise ◽  
Rectus Femoris ◽  
Peak Torque ◽  
Emg Activity ◽  
Neutral Position ◽  
Vastus Medialis ◽  
Maximal Voluntary Isometric Contraction

Context: It is very important to empirically determine the optimal ankle position for the quadriceps femoris (QF) strengthening during isometric exercises. Objective: To examine the effect of different ankle positions on torque and electromyography (EMG) activity of QF during maximal isometric contraction. Study Design: Within-subject repeated measures. Setting: University laboratory. Participants: Thirty-six healthy volunteers (15 males and 21 females). Main Outcome Measures: The isometric strength of the QF was measured at 3 different ankle positions: active dorsiflexion (AD), active plantar flexion (AP), and neutral position (NP). Simultaneously, 3 different ankle positions were assessed for EMG activity of the vastus medialis, vastus lateralis, and rectus femoris muscles during maximal voluntary isometric contraction. Results: The peak torque per body weight and average peak torque were significantly higher in AD than in AP and NP (P < .01). The vastus medialis and rectus femoris maximal voluntary isometric contraction EMG activity were significantly higher in AD than in AP and NP (P < .01). The vastus lateralis maximal voluntary isometric contraction EMG activity was significantly higher in AD than in AP and NP (P < .01), and was significantly higher in AP than in NP (P < .05). Conclusions: These results indicate that the 3 different ankle positions affect the QF torque and EMG activity. In particular, AD position may be more efficient for improving QF strength than AP and NP position. Future studies should prove whether long-term duration QF isometric exercise effects muscle strength and functional performance in different ankle positions.

A Comparison of Knee-Extension Torque Production with Biphasic versus Russian Current

2000 ◽  
Vol 9 (3) ◽  
pp. 229-239 ◽  
Author(s):  
William R. Holcomb ◽  
Shahin Golestani ◽  
Shante Hill
Keyword(s):  
Athletic Training ◽  
High Intensity ◽  
Repeated Measures ◽  
Outcome Measure ◽  
Maximum Voluntary Contraction ◽  
Neuromuscular Electrical Stimulation ◽  
Strength Loss ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Main Outcome Measure

Context:Neuromuscular electrical stimulation (NMES) can be used to prevent the atrophy and strength loss associated with immobilization.Objective:To compare the effects of biphasic current and the modulated “Russian” current on muscular torque production during different contraction conditions.Design, Setting, and Participants:In a within-subjects design, 10 healthy subjects in an athletic training laboratory received NMES.Interventions:Isometric knee-extension torque was recorded with the Biodex™ under 4 conditions: maximum voluntary contraction (MVC; control), MVC superimposed with low-intensity stimulation (sham), MVC superimposed with high-intensity stimulation, and high-intensity stimulation only.Main Outcome Measure:Data normalized for body weight were analyzed using a 2 (current type) X 4 (condition) repeated-measures analysis of variance.Results:The main effect for current type was not significant, F1,9 = .03, P = .87.

scholarly journals Central excitability does not limit postfatigue voluntary activation of quadriceps femoris

2006 ◽  
Vol 100 (6) ◽  
pp. 1757-1764 ◽  
Author(s):  
J. M. Kalmar ◽  
E. Cafarelli
Keyword(s):  
Evoked Potentials ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Motor Evoked Potentials ◽  
Vastus Lateralis ◽  
Central Fatigue ◽  
Knee Extension ◽  
Voluntary Activation ◽  
Fatigue Protocol ◽  
Central Excitability

After fatigue, motor evoked potentials (MEP) elicited by transcranial magnetic stimulation and cervicomedullary evoked potentials elicited by stimulation of the corticospinal tract are depressed. These reductions in corticomotor excitability and corticospinal transmission are accompanied by voluntary activation failure, but this may not reflect a causal relationship. Our purpose was to determine whether a decline in central excitability contributes to central fatigue. We hypothesized that, if central excitability limits voluntary activation, then a caffeine-induced increase in central excitability should offset voluntary activation failure. In this repeated-measures study, eight men each attended two sessions. Baseline measures of knee extension torque, maximal voluntary activation, peripheral transmission, contractile properties, and central excitability were made before administration of caffeine (6 mg/kg) or placebo. The amplitude of vastus lateralis MEPs elicited during minimal muscle activation provided a measure of central excitability. After a 1-h rest, baseline measures were repeated before, during, and after a fatigue protocol that ended when maximal voluntary torque declined by 35% (Tlim). Increased prefatigue MEP amplitude ( P = 0.055) and cortically evoked twitch ( P < 0.05) in the caffeine trial indicate that the drug increased central excitability. In the caffeine trial, increased MEP amplitude was correlated with time to task failure ( r = 0.74, P < 0.05). Caffeine potentiated the MEP early in the fatigue protocol ( P < 0.05) and offset the 40% decline in placebo MEP ( P < 0.05) at Tlim. However, this was not associated with enhanced maximal voluntary activation during fatigue or recovery, demonstrating that voluntary activation is not limited by central excitability.

scholarly journals Exploratory study of electromyographic behavior of the vastus medialis and vastus lateralis at neuromuscular fatigue onset

2014 ◽  
Vol 20 (2) ◽  
pp. 213-220 ◽  
Author(s):  
Cristiano Rocha da Silva ◽  
Danilo de Oliveira Silva ◽  
Deisi Ferrari ◽  
Rúben de Faria Negrão Filho ◽  
Neri Alves ◽  
...  
Keyword(s):  
Exploratory Study ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Neuromuscular Fatigue ◽  
Isometric Contractions ◽  
Median Frequency ◽  
Vastus Medialis ◽  
Mean Square ◽  
Electromyographic Signal ◽  
The Moment

This study aimed to determine and analyze the neuromuscular fatigue onset by median frequency (MDF) and the root mean square (RMS) behavior of an electromyographic signal (EMG). Eighteen healthy men with no prior knee problems initially performed three maximum voluntary isometric contractions (MVIC). After two days of MVIC test, participants performed a fatiguing protocol in which they performed submaximal knee-extension contractions at 20% and 70% MVIC held to exhaustion. The MDF and RMS values from the EMG signals were recorded from the vastus medialis (VM) and the vastus lateralis (VL). Analysis of the MDF and RMS behavior enabled identification of neuromuscular fatigue onset for VM and VL muscles in 20% and 70% loads. Alterations between the VM and VL in the neuromuscular fatigue onset, at 20% and 70% MVIC, were not significant. These findings suggest that the methodology proposal was capable of indicating minute differences sensible to alterations in the EMG signals, allowing identification of the moment when the MDF and the RMS showed significant changes in behavior. The methodology used was also a viable one for describing and identifying the neuromuscular fatigue onset by means of the analysis of EMG signals.

The Effects of Superficial Heating before 1-MHz Ultrasound on Tissue Temperature

2003 ◽  
Vol 12 (2) ◽  
pp. 95-103 ◽  
Author(s):  
William R. Holcomb ◽  
Chris Blank
Keyword(s):  
Athletic Training ◽  
Repeated Measures ◽  
Outcome Measure ◽  
Tissue Temperature ◽  
Temperature Elevation ◽  
Main Outcome Measure ◽  
Cooling Period ◽  
Dependent Variables ◽  
Within Subjects ◽  
Independent Variable

Context:Ultrasound significantly raises tissue temperature, but the time of temperature elevation is short.Objective:To assess the effectiveness of superficial preheating on temperature elevation and decline when using ultrasound.Design:Within-subjects design to test the independent variable, treatment condition; repeated-measures ANOVAs to analyze the dependent variables, temperature elevation and decline.Setting:Athletic training laboratory.Intervention:Temperature at a depth of 3.75 cm was measured during ultrasound after superficial heating and with ultrasound alone.Subjects:10 healthy men.Main Outcome Measure:Temperature was recorded every 30 s during 15 min of ultrasound and for 15 min afterward.Results:Temperature elevation with ultrasound was significantly greater with preheating (4.0 ± 0.21 °C) than with ultrasound alone (3.0 ± 0.22 °C). Temperature decline was not significantly different between preheating and ultrasound alone.Conclusions:Superficial preheating significantly increases temperature elevation but has no effect on temperature decline during a 15-min cooling period.

Surface EMG Evaluation of Patellofemoral Pain Syndrome in a Professional Ballet Dancer: A Case Report

2008 ◽  
Vol 23 (1) ◽  
pp. 29-32
Author(s):  
Walter Albisetti ◽  
Omar De Bartolomeo ◽  
Stella Gabbiadini ◽  
Alberto Ventura ◽  
Matteo Parrini
Keyword(s):  
Vastus Lateralis ◽  
Pain Syndrome ◽  
Surface Emg ◽  
Left Knee ◽  
Vastus Medialis ◽  
Ballet Dancer ◽  
Performing Artists ◽  
Vastus Medialis Obliquus ◽  
Patellar Maltracking ◽  
Asymmetric Activation

Objective: Because of the repetitive loading of the lower limb, patellar disorders are common in athletes and performing artists. Although this condition might be ascribed to different factors, the main cause is believed to be patellar maltracking. Design: Patellar maltracking is believed to be generated by an asymmetric activation of the vastus lateralis and vastus medialis obliquus muscles. A professional ballet dancer who suffered from anterior knee pain was examined. After clinical and MRI evaluations, he was subjected to surface electromyography (sEMG) of the vastus medialis obliquus and vastus lateralis. Results: We found a difference in the latency of onset of the vastus medialis obliquus and vastus lateralis of the painful right knee as compared to the asymptomatic left knee. Conclusion: Via sEMG, we demonstrate the role of the vastus medialis in patellar maltracking. sEMG is therefore a useful method to help diagnose and guide treatment in performing artists and elite athletes.

Motor units in vastus lateralis and in different vastus medialis regions show different firing properties during low-level, isometric knee extension contraction

2018 ◽  
Vol 58 ◽  
pp. 307-314 ◽  
Author(s):  
Leonardo Mendes Leal de Souza ◽  
Hélio Veiga Cabral ◽  
Liliam Fernandes de Oliveira ◽  
Taian Martins Vieira
Keyword(s):  
Vastus Lateralis ◽  
Motor Units ◽  
Knee Extension ◽  
Vastus Medialis ◽  
Low Level ◽  
Isometric Knee Extension ◽  
Firing Properties
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