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EMG Analysis of Patients with Unilateral Neck Pain

Robert L. Whalen, Steven P. Konstant, Teddy W. Worrell, and Sam Kegerreis

The purpose of this study was to determine whether differences exist in EMG activity between involved and uninvolved upper trapezius muscles in participants with unilateral neck pain. Thirteen volunteers, seen by a physical therapist, gave informed consent. Surface EMG electrodes were placed on involved and uninvolved upper trapezius muscles. Root mean squared EMG activity was measured. Visual analog scales (VASs) for pain were used for each side. Reliability data indicated high ICC (2,1) but also large SEMs and CVs. EMG activity increased from resting to shrugging to abducting positions. Participants perceived greater pain on the involved side than the uninvolved side. EMG readings for individuals were consistent, however, between participants. EMG had high variability. Although participants' VAS scores were consistent with their reports of unilateral neck pain, surface EMG readings did not support the existence of increased muscle activity on the involved side.

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Dynamic Analysis of Custom-Fitted Functional Knee Braces: EMG and Brace Migration during Physical Activity

John P. Miller, James C. Vailas, Ronald V. Croce, Robert Confessore, and Kerriann Catlaw

This study examined the effects of (a) functional knee braces on thigh muscle EMG and (b) physical activity and leg shape on knee brace migration. Ten female college ice hockey players were fitted with a strap-secured functional knee brace (SSB) and a hard-shell functional knee brace with strapping. Participants performed a side-step maneuver, a treadmill ran, and an obstacle course. Significant differences were noted in hamstring and quadriceps EMG median frequency (mfEMG) while wearing the SSB compared with the control condition. Significant downward shifts were noted in hamstring mfEMG for both braces when compared with the control condition. There was greater brace migration for the obstacle course for both brace types. No relation was found between leg shape and the amount of migration. This study suggests that custom-fitted functional knee braces alter the motor unit recruitment patterns of the thigh musculature during physical activity and that they do not migrate significantly during physical activity.

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Longer Integration Intervals Reduce Variability and Improve Reliability of EMG Derived from Maximal Isometric Exertions

Peter F. Vint and Richard N. Hinrichs

Isometric knee extension force and average integrated EMG of the vastus lateralis muscle were obtained from 27 healthy subjects using a maximum effort, ramp and hold protocol. In each of the 125 total trials mat were included in the analysis, a 2-s plateau region was extracted and divided into two adjacent 1000-ms bins. Variability and reliability of bin-to-bin measurements of force and EMG were then evaluated across 14 different integration intervals ranging from 10 to 1000 ms. Statistical analyses of bin-to-bin variability measures demonstrated that integration intervals of 250 ms and longer significantly reduced variability and improved reliability of average integrated EMG values during maximum effort isometric exertions. Bin-to-bin EMG reliability increased from .728 at 10 ms to .991 at 1000 ms. Force parameters appeared less sensitive to changes in length of the integration interval. It was suggested that longer intervals might also improve the validity of the EMG-force relationship during maximum effort isometric exertions by reducing problems associated with electromechanical delay.

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The Relationship Between Surface Electromyographic Activity and Torque Production of the Infraspinatus Muscle in Shoulder Rehabilitation Exercises

Bill Stodart, Maria Cup, and Curtis Kindel

The activity of a muscle as demonstrated by electromyography (EMG) is a common basis for exercise selection in current rehabilitation practice. 1 – 4 Shoulder exercises are no exception to this, as found in current relevant literature. 1 , 2 While EMG indicates the electrical activity of a

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Iterative Assessment of Statistically-Oriented and Standard Algorithms for Determining Muscle Onset with Intramuscular Electromyography

Matthew S. Tenan, Andrew J. Tweedell, and Courtney A. Haynes

The examination of muscle electromyography (EMG) burst timing in relation to external biomechanical events (eg, heel strike in gait) or in contrast to a secondary muscle (eg, vastus medialis oblique and vastus lateralis onset timing in patellofemoral pain) is used to understand how humans control

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Sensitivity of Neuromechanical Predictions to Choice of Glenohumeral Stability Modeling Approach

Daniel C. McFarland, Alexander G. Brynildsen, and Katherine R. Saul

metrics. To ameliorate this, researchers have proposed methods to incorporate cocontraction into optimization; 2 common approaches are constraining predicted muscle excitations to match magnitudes of normalized surface electromyography (EMG) signals within a tolerance 8 or constraining optimization to

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Rehabilitation Exercises for the Gluteus Medius Muscle Segments: An Electromyography Study

Damien Moore, Tania Pizzari, Jodie McClelland, and Adam I. Semciw

fine-wire electromyography (EMG) for the anterior, middle, and posterior GMed segments during 6 common rehabilitation exercises. This may assist clinicians with prescribing targeted rehabilitation programs to prevent, manage, or treat segmental GMed dysfunction that is evident in pathology. 4 , 5

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Comparison of Thoracic and Lumbar Erector Spinae Muscle Activation Before and After a Golf Practice Session

Graeme G. Sorbie, Fergal M. Grace, Yaodong Gu, Julien S. Baker, and Ukadike C. Ugbolue

Electromyography (EMG) is a study of muscle function that is analyzed through electrical activity. EMG analysis has become an important tool in many areas of research 1 and has been previously used to predict the loads placed on the musculoskeletal system, 2 as well as to examine prolonged muscle

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Muscle Activity Before and After Subacromial Injection

Lucas Ettinger, Matthew Shaprio, and Andrew Karduna

previously demonstrated that differences between studies could be methodological, where EMG activity is influenced by normalization to a maximal voluntary isometric contraction (MVIC) in the presence of pain. 15 To date, no study has measured deltoid activity in patients with impingement using normalization

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Rehabilitation Exercises for the Gluteus Minimus Muscle Segments: An Electromyography Study

Damien Moore, Adam I. Semciw, Jodie McClelland, Henry Wajswelner, and Tania Pizzari

-strengthening programs for people with lower-limb osteoarthritis. 23 – 25 The lack of research evaluating GMin function in exercise is likely due to the technical difficulty of accessing this muscle with intramuscular electromyography (EMG). 26 Some rehabilitation exercises for the GMin segments have been recently