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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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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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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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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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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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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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Mitchell L. Cordova, Lisa S. Jutte and J. Ty Hopkins

Many types of rehabilitation exercises are used to reestablish lower extremity neuromuscular function and strength following ankle injuries. It has not been established which exercise induces the greatest leg muscle activity, which might allow patients to recover more quickly from their injuries. The purpose of this investigation was to establish which exercises induce the most muscle activity in the medial gastrocnemius (MG), peroneus longus (PL), and tibialis anterior (TA), as measured by integrated electromyography (I-EMG). Participants (N = 24, age = 22 ± .59, mass = 63.5 ± 2.1 kg, ht = 165.7 ± 1.2 cm) conducted five repetitions of each of four exercise conditions for 30 s: one-legged stance (OLS), OLS on trampoline (OLST), T-Band kicks (TBK), and OLS perturbations (OLSP). It was found that the TBK exercise induces greater I-EMG in all three muscles, the OLST exercise stimulates more I-EMG activity in the MG and TA, and the OLSP exercise induces greater I-EMG activity in the TA.

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Gloria M. Beim, Jorge L. Giraldo, Danny M. Pincivero, Matthew J. Borror and Freddie H. Fu

The purpose of this study was to compare electromyographic (EMG) activity of the abdominal muscles between the crunch exercise and five other popular abdominal exercises. Surface EMG recordings of four muscles (upper rectus, lower rectus, external oblique, and internal oblique) of the anterior abdominal wall were collected and analyzed on 20 healthy, male volunteers. EMG activity was recorded during execution of the abdominal crunch, the sit-up, and exercises performed with the Abflex machine, the AbRoller, the Nordic Track Ab Works, and the Nautilus crunch machine. The results indicate that the crunch exercise is comparable to the five other abdominal exercises with respect to muscle activation of the internal and external abdominal oblique muscles. Activation of the upper rectus abdominal muscles appears to be best achieved with the Abflex machine, whereas the crunch exercise is superior to the sit-up for activation of the upper and lower rectus abdominal muscles.

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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

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David Phillips and Andrew Karduna

Electromyography (EMG) is a tool to determine the electrical behavior of muscles during a contraction. EMG can be measured simultaneously with an applied force to determine the relationship of EMG and an external load. This relationship may change depending on the rate of force development, 1