Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vii, 100 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Science in Medicine in the field of Biokinetics Johannesburg, 2017 / Background: Patellofemoral pain (PFP) is a common knee complaint associated with pain around the patella. Research has identified altered electromyographic (EMG) activity of the knee muscles in individuals with PFP compared to a healthy population (Briani et al., 2016). Purpose: The purpose of this observational study was to identify the EMG activity of the quadriceps muscle during functional activities in participants experiencing PFP and participants with no PFP. Methods: The onset and sequence timing including the ranking and Q-angle in relation to the rectus femoris (RF), vastus medialis obliquus (VMO) and vastus lateralis (VL) activity was measured with surface EMG in 17 PFP participants and 17 controls during a sit to stand, squat, and step up and step down. Results: The RM-ANOVA discovered a significant difference in the onset of VMO compared to RF muscle between the activities in the PFP group (-0.11 to 0.07 sec; p = 0.03) and the healthy group (-0.18 to -0.03; p = <0.01), as well as the VL compared to the RF muscle in the PFP group (-0.07 to 0.13 sec; p = <0.01). Significant differences were shown comparing the ranking of EMG onset for the quadriceps muscle to each activity in the healthy group (p = <0.01 to 0.04), and in the PFP group for the sit to stand (p = 0.01). Onset of VMO activity was predominantly ranked first in the healthy group (56%) and the VL in the PFP group (44%). A Mann-Whitney U-test shown a significant relationship in the healthy group between the Q-angle and the VMO, VL and RF muscles during the step down activity (r = -0.53 to -0.55; p = 0.02 to 0.03). Conclusion: This study confirms that the quadriceps muscle responds differently to different functional activities in the PFP and healthy population respectively. The healthy group tend to utilize the VMO first, compared to the PFP group with altered onset of quadriceps activation. Furthermore, the greater the Q-angle is, the earlier the onset of quadriceps muscle will be in the healthy group. This relationship was not found in the PFP group. / MT2017

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Lynn Snyder-Mackler, Dept. of Physical Therapy. Includes bibliographical references.

The stiff-knee gait pattern of children diagnosed with cerebral palsy (CP) is assumed to be caused by spasticity of the quadriceps which interferes with knee flexion normally occurring during the swing phase of walking. In current clinical practice, the ability to assess quadriceps spasticity is limited by the lack of an objective and reliable test that discriminates the role spasticity plays in functional limitations. The primary purpose of this series of studies was to assess the pendulum test as an objective measure of quadriceps spasticity. The first study assessed the reliability of the pendulum test. Moderate to very high between day reliability for all thirteen measures of the pendulum test were found. The second study assessed the discriminant ability of the pendulum test to correctly identify a stiff-knee gait pattern. Because most clinicians do not have access to a three dimensional motion analysis system, the third study assessed the reliability and accuracy of visual observation of the pendulum test. Sixty-eight children with a primary diagnosis of cerebral palsy participated. A three-dimensional motion analysis system was used to measure the subjects knee motion while walking, and performing the pendulum test. Spasticity of the quadriceps was also assessed using traditional clinical measures i.e., the modified Ashworth scale (MAS), and the Ely tests. Forty-seven percent of the variance in the stiff-knee gait pattern was explained by a regression model using the pendulum test and traditional clinical measures. The only significant measure in the regression model was the magnitude of knee motion occurring during the first swing of the pendulum test (A1). Discriminant analysis revealed the A1 measure correctly classified 77% of the subjects knee-gait pattern. Four observers demonstrated moderate accuracy and repeatability in estimating A1 value. The visual assessment of A1 correctly classified 72-76% of the subjects knee-gait pattern with no prior knowledge of the subjects gait. This series of studies demonstrated the pendulum test is an objective, repeatable measure of quadriceps spasticity. A negative pendulum test (indicated by an A1 value greater than 45 degrees) is more useful for ruling out a stiff-knee gait pattern compared to the traditional clinical measures.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Lynn Snyder-Mackler, Dept. of Physical Therapy. Includes bibliographical references.

Thesis (M.S.)--Indiana University, 2008. / Includes bibliographical references.

A relação entre eletromiografia e força é objeto de numerosos estudos, porém tal relação ainda não está totalmente elucidada e necessita de uma melhor fundamentação. Uma possível razão para as divergências entre esses estudos reside na dificuldade em determinar a força de um músculo individualmente de forma direta. Dentro deste contexto, procurou-se utilizar a análise do sinal eletromiográfico, associada a um modelo biomecânico do segmento articular para a avaliação das forças internas do músculo. O objetivo do presente trabalho é avaliar o comportamento eletromiográfico do músculo quadríceps durante exercícios isométricos e isotônicos concêntricos e correlacioná-lo com a força muscular, calculada através de simulações, usando modelos biomecânicos. Busca-se também uma forma de reconstruir a sobrecarga a que o músculo é submetido durante o exercício isotônico, através do tratamento do sinal eletromiográfico. Para tanto, o exercício isotônico é realizado em baixa velocidade e com pequena sobrecarga, e além disso, utiliza-se o procedimento de normalizar o sinal eletromiográfico ponto-a-ponto. Tal procedimento não possibilitou que a força externa, aplicada pelo membro, fosse obtida a partir do tratamento do sinal eletromiográfico, porém permitiu a correlação da eletromiografia com a força interna, gerada pelo músculo. Verificou-se também que a relação entre eletromiografia e força varia com a posição angular, com a força, com a velocidade de contração muscular e com a velocidade angular. No que se refere às análises da atividade isotônica, uma importante conclusão é que a relação entre eletromiografia e força não é linear; no entanto, quando normalizados pelos seus valores máximos podem ser considerados proporcionais. / The relationship between electromyography and force is largely investigated, however, such relation is not yet fully understood, still requiring better foundation. One of the reasons that might cause discrepancies between studies lies on directly calculating a single muscle force. Our approach handles the electromyographic signal coupled with a biomechanical model of the joint for assessment of internal muscle forces. This study aims at an evaluation of electromyographic behavior of the quadriceps muscle throughout isometric and concentric exercises, relating it to muscle force calculated by means of simulations, using biomechanical models. It is also handled in our study a means of assessing muscle overloading throughout dynamic exercises using eletromiographic signals. Accordingly, the dynamic exercise is undergone at slow speed and low resistance; and the electromyographic signal is normalized angle by angle. The approach did not allow the external force, produced by the limb, be assessed by means of electromyographic treatment, however, it allowed a relation between electromyography with internal force produced by the limb. It is worth mentioning that the electromyography-force relationship undergoes variations according to angular position, to degree of force, to muscle contraction velocity, to angular velocity. As to isotonic activity analysis, one important conclusion is the relation between electromyography and force is non-linear, with the proviso, that when normalized by peak values electromyography and force may be considered proportional.

Diss. (sammanfattning) Umeå : Umeå universitet, 2005. / Härtill 4 uppsatser.

Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

A relação entre eletromiografia e força é objeto de numerosos estudos, porém tal relação ainda não está totalmente elucidada e necessita de uma melhor fundamentação. Uma possível razão para as divergências entre esses estudos reside na dificuldade em determinar a força de um músculo individualmente de forma direta. Dentro deste contexto, procurou-se utilizar a análise do sinal eletromiográfico, associada a um modelo biomecânico do segmento articular para a avaliação das forças internas do músculo. O objetivo do presente trabalho é avaliar o comportamento eletromiográfico do músculo quadríceps durante exercícios isométricos e isotônicos concêntricos e correlacioná-lo com a força muscular, calculada através de simulações, usando modelos biomecânicos. Busca-se também uma forma de reconstruir a sobrecarga a que o músculo é submetido durante o exercício isotônico, através do tratamento do sinal eletromiográfico. Para tanto, o exercício isotônico é realizado em baixa velocidade e com pequena sobrecarga, e além disso, utiliza-se o procedimento de normalizar o sinal eletromiográfico ponto-a-ponto. Tal procedimento não possibilitou que a força externa, aplicada pelo membro, fosse obtida a partir do tratamento do sinal eletromiográfico, porém permitiu a correlação da eletromiografia com a força interna, gerada pelo músculo. Verificou-se também que a relação entre eletromiografia e força varia com a posição angular, com a força, com a velocidade de contração muscular e com a velocidade angular. No que se refere às análises da atividade isotônica, uma importante conclusão é que a relação entre eletromiografia e força não é linear; no entanto, quando normalizados pelos seus valores máximos podem ser considerados proporcionais. / The relationship between electromyography and force is largely investigated, however, such relation is not yet fully understood, still requiring better foundation. One of the reasons that might cause discrepancies between studies lies on directly calculating a single muscle force. Our approach handles the electromyographic signal coupled with a biomechanical model of the joint for assessment of internal muscle forces. This study aims at an evaluation of electromyographic behavior of the quadriceps muscle throughout isometric and concentric exercises, relating it to muscle force calculated by means of simulations, using biomechanical models. It is also handled in our study a means of assessing muscle overloading throughout dynamic exercises using eletromiographic signals. Accordingly, the dynamic exercise is undergone at slow speed and low resistance; and the electromyographic signal is normalized angle by angle. The approach did not allow the external force, produced by the limb, be assessed by means of electromyographic treatment, however, it allowed a relation between electromyography with internal force produced by the limb. It is worth mentioning that the electromyography-force relationship undergoes variations according to angular position, to degree of force, to muscle contraction velocity, to angular velocity. As to isotonic activity analysis, one important conclusion is the relation between electromyography and force is non-linear, with the proviso, that when normalized by peak values electromyography and force may be considered proportional.