The Effect of Patellar Taping on Quadriceps Activity Onset in the Absence of Pain

1999 ◽  
Vol 15 (4) ◽  
pp. 373-380 ◽  
Author(s):  
David Parsons ◽  
Wendy Gilleard
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Motor Units ◽  
Surface Emg ◽  
Mechanical Effect ◽  
Stair Ascent ◽  
Patella Position ◽  
The Right ◽  
Asymptomatic Subjects ◽  
Taping Technique

Patellofemoral taping is a technique used in the management of patellofemoral pain that has been shown to alter the pattern of muscle activation onset in symptomatic subjects. It is unknown, however, if this taping technique directly influences the patterns of muscle activity that controls patella position or if its benefits are more related to the effect of pain reduction. The purpose of this study was to investigate the effect of a taping technique on the muscle activation onset of selected quadriceps muscles where pain was not a confounding factor. Thirteen asymptomatic subjects completed a stair ascent and descent task with the right patella untaped and taped for a medial patella glide. Muscle activation onset was determined by computer algorithm from surface EMG of vastus lateralis (VL) and vastus medialis obliquus (VMO). Taping significantly delayed the muscle activation onset of VMO and VL during stair ascent. There was no significant change for stair descent. This effect may be an attempt by the motor control system to counter the mechanical effect of patella perturbation or may be due to cutaneous stimulation affecting threshold or recruitment of motor units.

scholarly journals The Electromyographic Threshold in Girls and Women

2017 ◽  
Vol 29 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Devon Long ◽  
Raffy Dotan ◽  
Brynlynn Pitt ◽  
Brandon McKinlay ◽  
Thomas D. O’Brien ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Regression Line ◽  
Surface Emg ◽  
Cycle Ergometry ◽  
High Threshold ◽  
Type Ii ◽  
Progressive Exercise ◽  
Muscular Function ◽  
The Right

Background:The electromyographic threshold (EMGTh) is thought to reflect increased high-threshold/type-II motor-unit (MU) recruitment and was shown higher in boys than in men. Women differ from men in muscular function.Purpose:Establish whether females’ EMGTh and girls–women differences are different than males’.Methods:Nineteen women (22.9 ± 3.3yrs) and 20 girls (10.3 ± 1.1yrs) had surface EMG recorded from the right and left vastus lateralis muscles during ramped cycle-ergometry to exhaustion. EMG root-mean-squares were averaged per pedal revolution. EMGTh was determined as the least residual sum of squares for any two regression-line data divisions, if the trace rose ≥ 3SD above its regression line. EMGTh was expressed as % final power-output (%Pmax) and %VO2pk power (%PVO2pk).Results:EMGTh was detected in 13 (68%) of women, but only 9 (45%) of girls (p < .005) and tended to be higher in the girls (%Pmax= 88.6 ± 7.0 vs. 83.0 ± 6.9%, p = .080; %PVO2pk= (101.6 ± 17.6 vs. 90.6 ± 7.8%, p = .063). When EMGTh was undetected it was assumed to occur at 100%Pmax or beyond. Consequently, EMGTh values turned significantly higher in girls than in women (94.8 ± 7.4 vs. 88.4 ± 9.9%Pmax, p = .026; and 103.2 ± 11.7 vs. 95.2 ± 9.9%PVO2pk, p = .028).Conclusions:During progressive exercise, girls appear to rely less on higher-threshold/type-II MUs than do women, suggesting differential muscle activation strategy.

scholarly journals The bilateral limb deficit (BLD) phenomenon during leg press: a preliminary investigation into central and peripheral factors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Emily Whitcomb ◽  
Oscar Ortiz ◽  
Jacqueline Toner ◽  
Usha Kuruganti
Keyword(s):  
Muscle Activation ◽  
Brain Activity ◽  
Vastus Lateralis ◽  
Preliminary Investigation ◽  
Rectus Femoris ◽  
Surface Emg ◽  
Leg Press ◽  
Bilateral Limb Deficit ◽  
Significant Difference ◽  
The Right

Abstract Background The bilateral limb deficit (BLD) phenomenon suggests that lower forces are produced with bilateral limb contractions compared to the summed force produced when the same muscles are contracted unilaterally. While interhemispheric inhibition has been suggested as a cause of BLD, the origin of the deficit is yet to be determined. The aim of this study was to investigate central and peripheral factors responsible for the BLD during leg press using surface electromyography (EMG) and electroencephalography (EEG). Methods Fourteen adults (age = 23.7 ± 4.7 years old) completed bilateral (BL), unilateral left (UL) and unilateral right (UR) isometric leg press exercises. Bilateral limb ratio (BLR) was calculated similar to previous studies and surface EMG from three muscles of the quadriceps femoris (vastus lateralis, vastus medialis and rectus femoris) was used to measure the level of muscle activation. Movement related cortical potentials (MRCPs) over the left and right motor cortex areas (C3 and C4, respectively) were used to assess brain activity asymmetries reflecting central factors. Results No significant difference was noted in the mean BLR (BLR = 94.8%), but a subset of ten participants did demonstrate a BLD (BLR = 81.4%, p < 0.01). Mean differences in relative activation were found among the three quadricep muscles (p < 0.001) with the right VM having significantly higher amplitude for the unilateral right (0.347 ± 0.318 mV) and bilateral right (0.436 ± 0.470 mV) conditions, respectively) than either the VL or RF (p < 0.05). The VL had significantly lower amplitudes in all conditions (0.127 ± 0.138 mV; 0.111 ± 0.104 mV; 0.120 ± 0.105 mV; 0.162 ± 0.147 mV for unilateral left, bilateral left, unilateral right, and bilateral right, respectively). However no overall significant differences were noted between bilateral and unilateral conditions. No significant differences in MRCPs were observed between brain activity of the C3 and C4 electrodes in any of the conditions. Conclusion While the sample size was low, this exploratory study noted the presence of BLD however the results did not provide evidence of significant limitations in either the EMG or EEG data.

Intent-Related Differences in Surface EMG of Maximum Eccentric and Concentric Contractions

2003 ◽  
Vol 19 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Mark D. Grabiner ◽  
Tammy M. Owings
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Eccentric Contraction ◽  
Surface Emg ◽  
Vastus Lateralis Muscle ◽  
Concentric Contractions ◽  
Concentric Contraction ◽  
Contraction Condition ◽  
The Difference

For this study it was hypothesized that when participants intended to perform a maximum voluntary concentric (or eccentric) contraction but had an eccentric (or concentric) contraction imposed upon them, the initial EMG measured during the isometric phase preceding the onset of the dynamometer motion would reflect the intended contraction condition. The surface EMG of the vastus lateralis muscle was measured in 24 participants performing isokinetic concentric and eccentric maximum voluntary knee extensor contractions. The contractions were initiated from rest and from the same knee flexion angle and required the same level of external force to trigger the onset of dynamometer motion. Vastus lateralis EMG were quantified during the isometric phase preceding the onset of the dynamometer motion. When participants intended to perform a concentric contraction but had an eccentric contraction imposed upon them, the initial EMG resembled that of a concentric contraction. When they intended to perform an eccentric contraction but had a concentric contraction imposed upon them, the initial EMG resembled that of an eccentric contraction. Overall, the difference between concentric and eccentric contractions observed during the period of theinitialmuscle activation implies that descending signals include information that distinguishes between eccentric and concentric contractions.

Effect of endurance training on muscle activation and force sensation

1995 ◽  
Vol 73 (12) ◽  
pp. 1765-1773 ◽  
Author(s):  
E. Cafarelli ◽  
F. Liebesman ◽  
J. Kroon
Keyword(s):  
Endurance Training ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Endurance Performance ◽  
Motor Units ◽  
Control Group ◽  
Reduction In Force ◽  
Leg Cycling ◽  
Before And After ◽  
And Control

One of the consequences of endurance training is a reduction in force sensation in trained muscles at any exercise intensity. To study the central and peripheral contributions to this adaptation, we trained six male subjects with single-leg cycling at 60% [Formula: see text] peak (30 min/day × 3 days/week × 8 weeks); six others were matched controls. Measurements were made during separate 20-min, single-leg rides at 70% pre-training [Formula: see text] peak, with trained (TR), untrained (UT), and control (CT) legs, before and after training. No pre–post differences were observed in the control group. [Formula: see text] peak increased 18% (p < 0.05) in the TR leg and 6% (p < 0.05) in the UT leg of the trained subjects. Force sensation was significantly less in both the TR (70%; p < 0.05) and UT (50%; p < 0.05) legs during 20 min of single-leg cycling after training. Vastus lateralis EMG, plasma lactate, and heart rate were all significantly (p < 0.05) lower when cycling with either the TR or UT leg, which were both lower than when cycling with the CT leg, at the end of each 20-min ride. These data reflect an intramuscular environment that is better adapted to endurance performance by virtue of both central and peripheral mechanisms. Thus, there is less need to recruit additional motor units to maintain the same power output, and this reduced motor outflow leads to a decline in force sensation.Key words: kinesthesia, proprioception, electromyography, single-leg training, endurance training.

Vastus lateralis surface and single motor unit EMG following submaximal shortening and lengthening contractions

2008 ◽  
Vol 33 (6) ◽  
pp. 1086-1095 ◽  
Author(s):  
Teatske M. Altenburg ◽  
Cornelis J. de Ruiter ◽  
Peter W.L. Verdijk ◽  
Willem van Mechelen ◽  
Arnold de Haan
Keyword(s):  
Motor Unit ◽  
Muscle Activation ◽  
Discharge Rate ◽  
Vastus Lateralis ◽  
Motor Units ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Single Motor Unit ◽  
Discharge Rates ◽  
Active Motor

A single shortening contraction reduces the force capacity of muscle fibers, whereas force capacity is enhanced following lengthening. However, how motor unit recruitment and discharge rate (muscle activation) are adapted to such changes in force capacity during submaximal contractions remains unknown. Additionally, there is limited evidence for force enhancement in larger muscles. We therefore investigated lengthening- and shortening-induced changes in activation of the knee extensors. We hypothesized that when the same submaximal torque had to be generated following shortening, muscle activation had to be increased, whereas a lower activation would suffice to produce the same torque following lengthening. Muscle activation following shortening and lengthening (20° at 10°/s) was determined using rectified surface electromyography (rsEMG) in a 1st session (at 10% and 50% maximal voluntary contraction (MVC)) and additionally with EMG of 42 vastus lateralis motor units recorded in a 2nd session (at 4%–47%MVC). rsEMG and motor unit discharge rates following shortening and lengthening were normalized to isometric reference contractions. As expected, normalized rsEMG (1.15 ± 0.19) and discharge rate (1.11 ± 0.09) were higher following shortening (p < 0.05). Following lengthening, normalized rsEMG (0.91 ± 0.10) was, as expected, lower than 1.0 (p < 0.05), but normalized discharge rate (0.99 ± 0.08) was not (p > 0.05). Thus, muscle activation was increased to compensate for a reduced force capacity following shortening by increasing the discharge rate of the active motor units (rate coding). In contrast, following lengthening, rsEMG decreased while the discharge rates of active motor units remained similar, suggesting that derecruitment of units might have occurred.

Motor Unit Interpulse Intervals During High Force Contractions

Motor Control ◽  
2016 ◽  
Vol 20 (1) ◽  
pp. 70-86 ◽  
Author(s):  
Matt S. Stock ◽  
Brennan J. Thompson
Keyword(s):  
Motor Unit ◽  
Polynomial Regression ◽  
Vastus Lateralis ◽  
Motor Units ◽  
Surface Emg ◽  
Voluntary Contraction ◽  
Emg Signal ◽  
Coefficients Of Variation ◽  
Low Threshold ◽  
The Relationship

We examined the means, medians, and variability for motor-unit interpulse intervals (IPIs) during voluntary, high force contractions. Eight men (mean age = 22 years) attempted to perform isometric contractions at 90% of their maximal voluntary contraction force while bipolar surface electromyographic (EMG) signals were detected from the vastus lateralis and vastus medialis muscles. Surface EMG signal decomposition was used to determine the recruitment thresholds and IPIs of motor units that demonstrated accuracy levels ≥ 96.0%. Motor units with high recruitment thresholds demonstrated longer mean IPIs, but the coefficients of variation were similar across all recruitment thresholds. Polynomial regression analyses indicated that for both muscles, the relationship between the means and standard deviations of the IPIs was linear. The majority of IPI histograms were positively skewed. Although low-threshold motor units were associated with shorter IPIs, the variability among motor units with differing recruitment thresholds was comparable.

Wearing an Inflatable Vest Alters Muscle Activation and Trunk Angle While Paddling a Surfboard

2017 ◽  
Vol 33 (4) ◽  
pp. 282-287 ◽  
Author(s):  
Jeff A. Nessler ◽  
Thomas Hastings ◽  
Kevin Greer ◽  
Sean C. Newcomer
Keyword(s):  
Muscle Activation ◽  
Random Order ◽  
Surface Emg ◽  
Erector Spinae ◽  
Low Back ◽  
Upper Trapezius ◽  
Lower Back ◽  
The Right ◽  
Trunk Extension ◽  
Order Surface

Low back pain is a commonly reported problem among recreational surfers. Some individuals report that wearing a vest with an inflatable bladder that alters trunk angle may help to alleviate pain. The purpose of this study was to determine whether such a vest has an effect on muscle activation and extension of the lower back. Twelve recreational surfers completed 12 paddling trials at 1.1 m/s in a swim flume on both a shortboard and a longboard on 2 separate days. Three conditions of no vest, vest uninflated, and vest inflated were presented to participants in random order. Surface EMG and trunk angle were acquired via wireless sensors placed over the right erector spinae, mid-trapezius, upper trapezius, and latissimus dorsi. Wearing the inflated vest affected muscle activation: erector spinae and mid-trapezius demonstrated a significant decrease in activation relative to wearing no vest (12% and 18% respectively, p < .05). Trunk extension was also significantly reduced when the vest was inflated (18% reduction, p < .05). Results were similar for both the short and longboard, though this effect was greater while paddling the larger board. These results suggest that a properly inflated vest can alter trunk extension and muscle activity while paddling a surfboard in water.

scholarly journals Onset of quadriceps activation and torque variation during stair ascent in individuals with patellofemoral pain

2013 ◽  
Vol 11 (4) ◽  
pp. 642-650 ◽  
Author(s):  
Heloyse Uliam Kuriki ◽  
Fábio Mícolis de Azevedo ◽  
Rúben De Faria Negrão Filho ◽  
Neri Alves
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Neuromuscular Disorders ◽  
Pain Syndrome ◽  
Patellofemoral Pain ◽  
Control Group ◽  
Stair Ascent ◽  
Simultaneous Activation ◽  
Control Pain ◽  
Motor Recruitment

Introduction: Studies have used surface electromyography (EMG) to understand motor recruitment in individuals with patellofemoral pain syndrome (PFPS); however, there is no consensus in the literature. Objective: To understand if, in addition to neuromuscular disorders, there are changes in rotational patterns in individuals with PFPS. Methods: Twenty-two control pain-free subjects and eleven subjects with PFPS were assessed during stair ascent with respect to the onset of muscle activation and percentage of torque variation (PTV). Result: The PFPS group showed previous activation of vastus lateralis (VL) (21.1 ± 58.1ms), while simultaneous activation was observed in the control group (2.8 ± 30.7ms, p=0.01). The groups also showed differences in relation to the PTV (p=0.02): the control group showed greater variation in torque (26.7 ± 35.3%) compared to the PFPS group (17.5 ± 35.9%). Conclusion: People with PFPS have prior activation of VL and lower tendency towards body rotation, which may suggest patellar lateralization.

Trunk Muscle Activation While Resisting Asymmetrically Applied Loads in an Axially Rotated Posture

1992 ◽  
Vol 36 (10) ◽  
pp. 752-756
Author(s):  
Steven A. Lavender ◽  
Yang-Hwei Tsuang ◽  
Gunnar B.J. Andersson
Keyword(s):  
Muscle Activation ◽  
Surface Emg ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Rectus Abdominus ◽  
Left And Right ◽  
External Oblique ◽  
The Right ◽  
Main Effects ◽  
Univariate Analyses

The present investigation describes the electromyographic (EMG) response of eight trunk muscles during the application of loads to the torso while subjects maintained a twisted posture. The external moments of 20 and 40 Nm were applied to a harness system as each of the 10 subjects twisted 25 degrees. The applied moment direction was varied in 3 0 degree increments completely around the subjects (0 to 33 0 degrees). Surface EMG was used to monitor the left and right Latissimus Dorsi, Erector Spinae, External Oblique, and Rectus Abdominus. Multivariate and univariate analyses of variance (MANOVA and ANOVA) procedures showed significant main effects for all muscles and a significant moment magnitude by moment direction interaction effect in 6 of the 8 muscles. The greatest muscle activity was observed in the right Erector Spinae and the left External Oblique muscles. The results are also compared with an earlier study in which a similar loading paradigm was used as subject maintained a neutral upright posture.

scholarly journals The Surface EMG Characteristics between Erector Spinae and Vastus Lateralis during Bending Forward and Squatting Down Tasks

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jinzhuang Xiao ◽  
Junmin Gao ◽  
Hongrui Wang ◽  
Kun Liu ◽  
Xincai Yang
Keyword(s):  
Theoretical Basis ◽  
Healthy Subjects ◽  
Vastus Lateralis ◽  
Surface Emg ◽  
Physical Activities ◽  
Erector Spinae ◽  
Median Frequency ◽  
Low Back ◽  
The Right ◽  
Daily Physical Activities

Bending forward and squatting down are two common physical tasks in everyday life and at work. This study determined the sEMG characteristics between erector spinae and vastus lateralis during bending forward and squatting down tasks by analyzing the regularity of variation in sEMG frequency domain index-median frequency (MNF) in healthy subjects. The results indicate that sEMG activities in erector spinae are significantly higher than those in the right vastus lateralis during bending forward task. Instead, in squatting down task, sEMG activities in the right vastus lateralis are significantly greater than those in erector spinae. It also shows that the fatigue degree of low back caused by trunk bending is much deeper than that by squatting down. The ratio scope of one-order fitting values of MNF between erector spinae and vastus lateralis ranges from 0.87 to 1.72 among 80% of subjects during bending forward task and ranges from 0.31 to 1.11 during squatting down task. This study provides certain theoretical basis for using the strength of low back in a proper way to avoid getting it hurt in daily physical activities.

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