The Experts below are selected from a list of 568680 Experts worldwide ranked by ideXlab platform

Joseph P. Weir - One of the best experts on this subject based on the ideXlab platform.

  • the influence of electromyographic recording methods and the innervation zone on the mean Power Frequency torque relationships
    Journal of Electromyography and Kinesiology, 2015
    Co-Authors: Trent J Herda, Jorge M Zuniga, Clayton L Camic, Haley C Bergstrom, Eric D Ryan, Doug B Smith, Joseph P. Weir
    Abstract:

    Abstract This study examined the effects of electromyographic (EMG) recording methods and innervation zone (IZ) on the mean Power Frequency (MPF)–torque relationships. Nine subjects performed isometric ramp muscle actions of the leg extensors from 5% to 100% of maximal voluntary contraction with an eight channel linear electrode array over the IZ of the vastus lateralis. The slopes were calculated from the log-transformed monopolar and bipolar EMG MPF–torque relationships for each channel and subject and 95% confidence intervals (CI) were constructed around the slopes for each relationship and the composite of the slopes. Twenty-two to 55% of the subjects exhibited 95% CIs that did not include a slope of zero for the monopolar EMG MPF–torque relationships while 25–75% of the subjects exhibited 95% CIs that did not include a slope of zero for the bipolar EMG MPF–torque relationships. The composite of the slopes from the EMG MPF–torque relationships were not significantly different from zero for any method or channel, however, the method and IZ location slightly influenced the number of significant slopes on a subject-by-subject basis. The log-transform model indicated that EMG MPF–torque patterns were nonlinear regardless of recording method or distance from the IZ.

  • the effects of interelectrode distance over the innervation zone and normalization on the electromyographic amplitude and mean Power Frequency versus concentric eccentric and isometric torque relationships for the vastus lateralis muscle
    Journal of Electromyography and Kinesiology, 2009
    Co-Authors: Joseph P. Weir
    Abstract:

    Abstract The purpose of this study was to examine the influence of interelectrode distance (IED) over the estimated innervation zone (IZ) for the vastus lateralis muscle and normalization on the torque-related patterns of responses for electromyographic (EMG) amplitude and mean Power Frequency (MPF) during concentric isokinetic, eccentric isokinetic, and isometric muscle actions of the leg extensors. Eight men performed submaximal to maximal concentric isokinetic, eccentric isokinetic, and isometric muscle actions of the dominant leg extensors. Surface EMG signals were recorded simultaneously with two bipolar electrode arrangements in single differential configuration (20 and 40mm IEDs) placed over the estimated IZ for the vastus lateralis muscle and a third electrode arrangement in single differential configuration (20mm IED) placed distal to the estimated IZ. The results indicated that there were only a few (six of 90 statistical comparisons) significant ( p

  • the effects of electrode placement and innervation zone location on the electromyographic amplitude and mean Power Frequency versus isometric torque relationships for the vastus lateralis muscle
    Journal of Electromyography and Kinesiology, 2008
    Co-Authors: Joseph P. Weir
    Abstract:

    Abstract The purposes of this investigation were to examine the effects of electrode placement and innervation zone (IZ) location on: (a) the torque-related patterns of responses for absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) and (b) the mean absolute and normalized EMG amplitude and MPF values. In addition, the present study examined the variability between subjects for the location of the IZ for the vastus lateralis (VL). Eight men (mean±SD age=23.0±4.3yr) performed submaximal to maximal isometric muscle actions of the dominant leg extensors. During each muscle action, fifteen channels of bipolar surface EMG signals were detected from the vastus lateralis using a linear electrode array aligned with the long axis of the muscle fibers. The results indicated that there were differences among channels 1–15 for the patterns of responses and mean values for absolute and normalized EMG amplitude and MPF versus isometric torque. Thus, normalized EMG amplitude and MPF values from different individuals cannot be compared if the EMG signals were detected from different locations over the muscle. In addition, absolute and relative (to femur length) estimates of IZ location for the VL resulted in similar inter-subject variability.

  • the effects of electrode placement and innervation zone location on the electromyographic amplitude and mean Power Frequency versus isometric torque relationships for the vastus lateralis muscle
    Journal of Electromyography and Kinesiology, 2008
    Co-Authors: Travis W Beck, Terry J Housh, Joel T Cramer, Joseph P. Weir
    Abstract:

    Abstract The purposes of this investigation were to examine the effects of electrode placement and innervation zone (IZ) location on: (a) the torque-related patterns of responses for absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) and (b) the mean absolute and normalized EMG amplitude and MPF values. In addition, the present study examined the variability between subjects for the location of the IZ for the vastus lateralis (VL). Eight men (mean±SD age=23.0±4.3yr) performed submaximal to maximal isometric muscle actions of the dominant leg extensors. During each muscle action, fifteen channels of bipolar surface EMG signals were detected from the vastus lateralis using a linear electrode array aligned with the long axis of the muscle fibers. The results indicated that there were differences among channels 1–15 for the patterns of responses and mean values for absolute and normalized EMG amplitude and MPF versus isometric torque. Thus, normalized EMG amplitude and MPF values from different individuals cannot be compared if the EMG signals were detected from different locations over the muscle. In addition, absolute and relative (to femur length) estimates of IZ location for the VL resulted in similar inter-subject variability.

  • the influence of electrode placement over the innervation zone on electromyographic amplitude and mean Power Frequency versus isokinetic torque relationships
    Journal of Neuroscience Methods, 2007
    Co-Authors: Michelle Mielke, Joseph P. Weir, Moh H Malek, Glen O Johnson
    Abstract:

    The purpose of this investigation was to examine the influence of electrode placement over the estimated innervation zone (IZ) for the vastus lateralis, as well as proximal and distal to the estimated IZ, on the torque-related patterns for electromyographic (EMG) amplitude and mean Power Frequency (MPF) during concentric and eccentric isokinetic muscle actions of the leg extensors. Eleven men performed randomly ordered, submaximal to maximal concentric and eccentric isokinetic muscle actions of the dominant leg extensors in 10% increments from 10 to 90% peak torque (PT). Surface EMG signals were recorded simultaneously from the vastus lateralis muscle with bipolar electrode arrangements placed over the estimated IZ, as well as proximal and distal to the estimated IZ. The results indicated that there were no consistent differences among the proximal, IZ, and distal electrode placement sites for the patterns of responses for absolute and normalized EMG amplitude and MPF versus torque, or the mean absolute and normalized EMG amplitude and MPF values. Thus, these findings suggested that during concentric and eccentric isokinetic muscle actions of the leg extensors, electrode placement over the estimated IZ for the vastus lateralis had no effect on the patterns of responses or mean values for absolute and normalized EMG amplitude and MPF versus torque.

Moh H Malek - One of the best experts on this subject based on the ideXlab platform.

  • comparison of mechanomyographic amplitude and mean Power Frequency for the rectus femoris muscle cycle versus knee extensor ergometry
    Journal of Neuroscience Methods, 2009
    Co-Authors: Moh H Malek, Jared W Coburn, Vince Tedjasaputra
    Abstract:

    The purpose of this study was to compare the mechanomyographic (MMG) amplitude and mean Power Frequency (MPF) versus Power output relationships for the rectus femoris (RF) muscle during incremental cycle (CE) and knee-extensor (KE) ergometry in the same subjects. Eight men performed incremental CE and KE tests to exhaustion while the MMG signal was recorded from the RF muscle. Polynomial regression analyses on the composite and subject-by-subject basis indicated that the relationship between MMG amplitude versus Power output was best-fit with a linear model for the composite data and each subject for the KE test, whereas the relationship was best-fit with a linear model for the composite data, but either linear, quadratic, or cubic for the CE test. In addition, there were no consistent patterns of responses for either the CE or KE test for MMG MPF. These results suggest that KE rather than traditional CE exercise may be an optimal mode of examining MMG amplitude for the RF muscle.

  • the influence of electrode placement over the innervation zone on electromyographic amplitude and mean Power Frequency versus isokinetic torque relationships
    Journal of Neuroscience Methods, 2007
    Co-Authors: Michelle Mielke, Joseph P. Weir, Moh H Malek, Glen O Johnson
    Abstract:

    The purpose of this investigation was to examine the influence of electrode placement over the estimated innervation zone (IZ) for the vastus lateralis, as well as proximal and distal to the estimated IZ, on the torque-related patterns for electromyographic (EMG) amplitude and mean Power Frequency (MPF) during concentric and eccentric isokinetic muscle actions of the leg extensors. Eleven men performed randomly ordered, submaximal to maximal concentric and eccentric isokinetic muscle actions of the dominant leg extensors in 10% increments from 10 to 90% peak torque (PT). Surface EMG signals were recorded simultaneously from the vastus lateralis muscle with bipolar electrode arrangements placed over the estimated IZ, as well as proximal and distal to the estimated IZ. The results indicated that there were no consistent differences among the proximal, IZ, and distal electrode placement sites for the patterns of responses for absolute and normalized EMG amplitude and MPF versus torque, or the mean absolute and normalized EMG amplitude and MPF values. Thus, these findings suggested that during concentric and eccentric isokinetic muscle actions of the leg extensors, electrode placement over the estimated IZ for the vastus lateralis had no effect on the patterns of responses or mean values for absolute and normalized EMG amplitude and MPF versus torque.

  • the effects of innervation zone on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir
    Abstract:

    Abstract The purpose of this study was to examine the effects of electrode placements over the innervation zone (IZ), as well as proximal and distal to the IZ, on the patterns for the absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) versus Power output relationships during incremental cycle ergometry. Fifteen men [mean ± S.D. age = 24.3 ± 2.4 years; V ˙ O 2 max = 47.3 ± 4.9 ml k g − 1 mi n − 1 ] performed incremental cycle ergometry tests to exhaustion. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed on the vastus lateralis (VL) muscle over the IZ, as well as proximal and distal to the IZ. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (μVrms and %max) and MPF (Hz and %max) versus Power output (%max) for each subject at the three electrode placement sites. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three sites for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression analyses revealed that the best fit model for each site for the absolute and normalized EMG amplitude versus Power output relationship was linear for 11 subjects and quadratic for 2 subjects. The remaining two subjects exhibited both linear and quadratic patterns that were site-dependent. For EMG MPF, 10 subjects exhibited significant relationships (linear and/or quadratic) across Power outputs for at least one site. In addition, there were significant ( P  0.05) mean differences between the electrode placement sites for absolute EMG amplitude, but not absolute EMG MPF at 80, 110, 140, and 170 W. There were no significant ( P >  0.05) mean differences, however, between the three sites for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. These findings indicated that the placement of bipolar electrodes over the IZ, as well as proximal and distal to the IZ, had no effect on the pattern of the normalized EMG amplitude versus Power output relationship or the mean normalized EMG amplitude and MPF values. Thus, during cycle ergometry, normalized EMG amplitude values (but not absolute values) can be compared between studies that have utilized various electrode placement sites on the VL.

  • the effects of innervation zone on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Travis W Beck, Terry J Housh
    Abstract:

    Abstract The purpose of this study was to examine the effects of electrode placements over the innervation zone (IZ), as well as proximal and distal to the IZ, on the patterns for the absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) versus Power output relationships during incremental cycle ergometry. Fifteen men [mean ± S.D. age = 24.3 ± 2.4 years; V ˙ O 2 max = 47.3 ± 4.9 ml k g − 1 mi n − 1 ] performed incremental cycle ergometry tests to exhaustion. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed on the vastus lateralis (VL) muscle over the IZ, as well as proximal and distal to the IZ. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (μVrms and %max) and MPF (Hz and %max) versus Power output (%max) for each subject at the three electrode placement sites. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three sites for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression analyses revealed that the best fit model for each site for the absolute and normalized EMG amplitude versus Power output relationship was linear for 11 subjects and quadratic for 2 subjects. The remaining two subjects exhibited both linear and quadratic patterns that were site-dependent. For EMG MPF, 10 subjects exhibited significant relationships (linear and/or quadratic) across Power outputs for at least one site. In addition, there were significant (P   0.05) mean differences, however, between the three sites for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. These findings indicated that the placement of bipolar electrodes over the IZ, as well as proximal and distal to the IZ, had no effect on the pattern of the normalized EMG amplitude versus Power output relationship or the mean normalized EMG amplitude and MPF values. Thus, during cycle ergometry, normalized EMG amplitude values (but not absolute values) can be compared between studies that have utilized various electrode placement sites on the VL.

  • the effects of interelectrode distance on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Terry J Housh, Richard J Schmidt, Travis W Beck
    Abstract:

    The purpose of this study was to examine the effects of interelectrode distance (IED) on the relationships of absolute and normalized EMG amplitude and mean Power Frequency (MPF) versus Power output during incremental cycle ergometry. Eleven adults (mean +/- S.D. age = 24.2 +/- 2.6 y; V(O2max) = 49.4 +/- 8.3 ml kg(-1) min(-1)) performed incremental cycle ergometry tests. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed over the VL muscle with IEDs of 20, 40, and 60 mm. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (muV(rms) and % max) and MPF (Hz and % max) versus Power output (%max) for each subject at the three IEDs. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three IEDs for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression revealed that the best fit model for each IED for the absolute and normalized EMG amplitude was linear for six of the 11 subjects and quadratic for five of the subjects. For EMG MPF, four of the 11 subjects exhibited significant relationships (linear or quadratic) across Power outputs for at least one IED. The one-way repeated measures ANOVAs revealed significant mean differences between the IEDs for absolute EMG amplitude and MPF at 80, 110, 140, and 170 W. There were no significant mean differences, however, between the IEDs for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. The results of the study indicated that there were no consistent patterns of responses between individual subjects for EMG amplitude or MPF versus Power output relationships for IEDs of 20, 40, and 60 mm during incremental cycle ergometry. The current findings supported the process of normalization for EMG amplitude and MPF data obtained during cycle ergometry when comparisons are made for different IEDs.

Travis W Beck - One of the best experts on this subject based on the ideXlab platform.

  • the effects of electrode placement and innervation zone location on the electromyographic amplitude and mean Power Frequency versus isometric torque relationships for the vastus lateralis muscle
    Journal of Electromyography and Kinesiology, 2008
    Co-Authors: Travis W Beck, Terry J Housh, Joel T Cramer, Joseph P. Weir
    Abstract:

    Abstract The purposes of this investigation were to examine the effects of electrode placement and innervation zone (IZ) location on: (a) the torque-related patterns of responses for absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) and (b) the mean absolute and normalized EMG amplitude and MPF values. In addition, the present study examined the variability between subjects for the location of the IZ for the vastus lateralis (VL). Eight men (mean±SD age=23.0±4.3yr) performed submaximal to maximal isometric muscle actions of the dominant leg extensors. During each muscle action, fifteen channels of bipolar surface EMG signals were detected from the vastus lateralis using a linear electrode array aligned with the long axis of the muscle fibers. The results indicated that there were differences among channels 1–15 for the patterns of responses and mean values for absolute and normalized EMG amplitude and MPF versus isometric torque. Thus, normalized EMG amplitude and MPF values from different individuals cannot be compared if the EMG signals were detected from different locations over the muscle. In addition, absolute and relative (to femur length) estimates of IZ location for the VL resulted in similar inter-subject variability.

  • the effects of innervation zone on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Travis W Beck, Terry J Housh
    Abstract:

    Abstract The purpose of this study was to examine the effects of electrode placements over the innervation zone (IZ), as well as proximal and distal to the IZ, on the patterns for the absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) versus Power output relationships during incremental cycle ergometry. Fifteen men [mean ± S.D. age = 24.3 ± 2.4 years; V ˙ O 2 max = 47.3 ± 4.9 ml k g − 1 mi n − 1 ] performed incremental cycle ergometry tests to exhaustion. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed on the vastus lateralis (VL) muscle over the IZ, as well as proximal and distal to the IZ. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (μVrms and %max) and MPF (Hz and %max) versus Power output (%max) for each subject at the three electrode placement sites. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three sites for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression analyses revealed that the best fit model for each site for the absolute and normalized EMG amplitude versus Power output relationship was linear for 11 subjects and quadratic for 2 subjects. The remaining two subjects exhibited both linear and quadratic patterns that were site-dependent. For EMG MPF, 10 subjects exhibited significant relationships (linear and/or quadratic) across Power outputs for at least one site. In addition, there were significant (P   0.05) mean differences, however, between the three sites for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. These findings indicated that the placement of bipolar electrodes over the IZ, as well as proximal and distal to the IZ, had no effect on the pattern of the normalized EMG amplitude versus Power output relationship or the mean normalized EMG amplitude and MPF values. Thus, during cycle ergometry, normalized EMG amplitude values (but not absolute values) can be compared between studies that have utilized various electrode placement sites on the VL.

  • the effects of interelectrode distance on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Terry J Housh, Richard J Schmidt, Travis W Beck
    Abstract:

    The purpose of this study was to examine the effects of interelectrode distance (IED) on the relationships of absolute and normalized EMG amplitude and mean Power Frequency (MPF) versus Power output during incremental cycle ergometry. Eleven adults (mean +/- S.D. age = 24.2 +/- 2.6 y; V(O2max) = 49.4 +/- 8.3 ml kg(-1) min(-1)) performed incremental cycle ergometry tests. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed over the VL muscle with IEDs of 20, 40, and 60 mm. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (muV(rms) and % max) and MPF (Hz and % max) versus Power output (%max) for each subject at the three IEDs. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three IEDs for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression revealed that the best fit model for each IED for the absolute and normalized EMG amplitude was linear for six of the 11 subjects and quadratic for five of the subjects. For EMG MPF, four of the 11 subjects exhibited significant relationships (linear or quadratic) across Power outputs for at least one IED. The one-way repeated measures ANOVAs revealed significant mean differences between the IEDs for absolute EMG amplitude and MPF at 80, 110, 140, and 170 W. There were no significant mean differences, however, between the IEDs for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. The results of the study indicated that there were no consistent patterns of responses between individual subjects for EMG amplitude or MPF versus Power output relationships for IEDs of 20, 40, and 60 mm during incremental cycle ergometry. The current findings supported the process of normalization for EMG amplitude and MPF data obtained during cycle ergometry when comparisons are made for different IEDs.

  • mechanomyographic amplitude and mean Power Frequency versus torque relationships during isokinetic and isometric muscle actions of the biceps brachii
    Journal of Electromyography and Kinesiology, 2004
    Co-Authors: Travis W Beck, Glen O Johnson, Jared W Coburn, Joseph P. Weir, Terry J Housh, Joel T Cramer, Moh H Malek
    Abstract:

    Abstract The purpose of this investigation was to determine the mechanomyographic (MMG) amplitude and mean Power Frequency (MPF) versus torque (or force) relationships during isokinetic and isometric muscle actions of the biceps brachii. Ten adults (mean±SD age=21.6±1.7 years) performed submaximal to maximal isokinetic and isometric muscle actions of the dominant forearm flexors. Following determination of isokinetic peak torque (PT) and the isometric maximum voluntary contraction (MVC), the subjects randomly performed submaximal step muscle actions in 10% increments from 10% to 90% PT and MVC. Polynomial regression analyses indicated that MMG amplitude increased linearly with torque during both the isokinetic ( r 2 =0.982) and isometric ( r 2 =0.956) muscle actions. From 80% to 100% of isometric MVC, however, MMG amplitude appeared to plateau. Cubic models provided the best fit for the MMG MPF versus isokinetic ( R 2 =0.786) and isometric ( R 2 =0.940) torque relationships, although no significant increase in MMG MPF was found from 10% to 100% of isokinetic PT. For the isometric muscle actions, however, MMG MPF remained relatively stable from 10% to 50% MVC, increased from 50% to 80% MVC, and decreased from 80% to 100% MVC. The results demonstrated differences in the MMG amplitude and MPF versus torque relationships between the isokinetic and isometric muscle actions. These findings suggested that the time and Frequency domains of the MMG signal may be useful for describing the unique motor control strategies that modulate dynamic versus isometric torque production.

Terry J Housh - One of the best experts on this subject based on the ideXlab platform.

  • the effects of electrode placement and innervation zone location on the electromyographic amplitude and mean Power Frequency versus isometric torque relationships for the vastus lateralis muscle
    Journal of Electromyography and Kinesiology, 2008
    Co-Authors: Travis W Beck, Terry J Housh, Joel T Cramer, Joseph P. Weir
    Abstract:

    Abstract The purposes of this investigation were to examine the effects of electrode placement and innervation zone (IZ) location on: (a) the torque-related patterns of responses for absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) and (b) the mean absolute and normalized EMG amplitude and MPF values. In addition, the present study examined the variability between subjects for the location of the IZ for the vastus lateralis (VL). Eight men (mean±SD age=23.0±4.3yr) performed submaximal to maximal isometric muscle actions of the dominant leg extensors. During each muscle action, fifteen channels of bipolar surface EMG signals were detected from the vastus lateralis using a linear electrode array aligned with the long axis of the muscle fibers. The results indicated that there were differences among channels 1–15 for the patterns of responses and mean values for absolute and normalized EMG amplitude and MPF versus isometric torque. Thus, normalized EMG amplitude and MPF values from different individuals cannot be compared if the EMG signals were detected from different locations over the muscle. In addition, absolute and relative (to femur length) estimates of IZ location for the VL resulted in similar inter-subject variability.

  • the effects of innervation zone on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Travis W Beck, Terry J Housh
    Abstract:

    Abstract The purpose of this study was to examine the effects of electrode placements over the innervation zone (IZ), as well as proximal and distal to the IZ, on the patterns for the absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) versus Power output relationships during incremental cycle ergometry. Fifteen men [mean ± S.D. age = 24.3 ± 2.4 years; V ˙ O 2 max = 47.3 ± 4.9 ml k g − 1 mi n − 1 ] performed incremental cycle ergometry tests to exhaustion. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed on the vastus lateralis (VL) muscle over the IZ, as well as proximal and distal to the IZ. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (μVrms and %max) and MPF (Hz and %max) versus Power output (%max) for each subject at the three electrode placement sites. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three sites for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression analyses revealed that the best fit model for each site for the absolute and normalized EMG amplitude versus Power output relationship was linear for 11 subjects and quadratic for 2 subjects. The remaining two subjects exhibited both linear and quadratic patterns that were site-dependent. For EMG MPF, 10 subjects exhibited significant relationships (linear and/or quadratic) across Power outputs for at least one site. In addition, there were significant (P   0.05) mean differences, however, between the three sites for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. These findings indicated that the placement of bipolar electrodes over the IZ, as well as proximal and distal to the IZ, had no effect on the pattern of the normalized EMG amplitude versus Power output relationship or the mean normalized EMG amplitude and MPF values. Thus, during cycle ergometry, normalized EMG amplitude values (but not absolute values) can be compared between studies that have utilized various electrode placement sites on the VL.

  • the effects of interelectrode distance on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Terry J Housh, Richard J Schmidt, Travis W Beck
    Abstract:

    The purpose of this study was to examine the effects of interelectrode distance (IED) on the relationships of absolute and normalized EMG amplitude and mean Power Frequency (MPF) versus Power output during incremental cycle ergometry. Eleven adults (mean +/- S.D. age = 24.2 +/- 2.6 y; V(O2max) = 49.4 +/- 8.3 ml kg(-1) min(-1)) performed incremental cycle ergometry tests. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed over the VL muscle with IEDs of 20, 40, and 60 mm. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (muV(rms) and % max) and MPF (Hz and % max) versus Power output (%max) for each subject at the three IEDs. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three IEDs for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression revealed that the best fit model for each IED for the absolute and normalized EMG amplitude was linear for six of the 11 subjects and quadratic for five of the subjects. For EMG MPF, four of the 11 subjects exhibited significant relationships (linear or quadratic) across Power outputs for at least one IED. The one-way repeated measures ANOVAs revealed significant mean differences between the IEDs for absolute EMG amplitude and MPF at 80, 110, 140, and 170 W. There were no significant mean differences, however, between the IEDs for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. The results of the study indicated that there were no consistent patterns of responses between individual subjects for EMG amplitude or MPF versus Power output relationships for IEDs of 20, 40, and 60 mm during incremental cycle ergometry. The current findings supported the process of normalization for EMG amplitude and MPF data obtained during cycle ergometry when comparisons are made for different IEDs.

  • mechanomyographic amplitude and mean Power Frequency versus torque relationships during isokinetic and isometric muscle actions of the biceps brachii
    Journal of Electromyography and Kinesiology, 2004
    Co-Authors: Travis W Beck, Glen O Johnson, Jared W Coburn, Joseph P. Weir, Terry J Housh, Joel T Cramer, Moh H Malek
    Abstract:

    Abstract The purpose of this investigation was to determine the mechanomyographic (MMG) amplitude and mean Power Frequency (MPF) versus torque (or force) relationships during isokinetic and isometric muscle actions of the biceps brachii. Ten adults (mean±SD age=21.6±1.7 years) performed submaximal to maximal isokinetic and isometric muscle actions of the dominant forearm flexors. Following determination of isokinetic peak torque (PT) and the isometric maximum voluntary contraction (MVC), the subjects randomly performed submaximal step muscle actions in 10% increments from 10% to 90% PT and MVC. Polynomial regression analyses indicated that MMG amplitude increased linearly with torque during both the isokinetic ( r 2 =0.982) and isometric ( r 2 =0.956) muscle actions. From 80% to 100% of isometric MVC, however, MMG amplitude appeared to plateau. Cubic models provided the best fit for the MMG MPF versus isokinetic ( R 2 =0.786) and isometric ( R 2 =0.940) torque relationships, although no significant increase in MMG MPF was found from 10% to 100% of isokinetic PT. For the isometric muscle actions, however, MMG MPF remained relatively stable from 10% to 50% MVC, increased from 50% to 80% MVC, and decreased from 80% to 100% MVC. The results demonstrated differences in the MMG amplitude and MPF versus torque relationships between the isokinetic and isometric muscle actions. These findings suggested that the time and Frequency domains of the MMG signal may be useful for describing the unique motor control strategies that modulate dynamic versus isometric torque production.

  • mean Power Frequency and amplitude of the mechanomyographic and electromyographic signals during incremental cycle ergometry
    Journal of Electromyography and Kinesiology, 2001
    Co-Authors: S R Perry, Glen O Johnson, Joseph P. Weir, Terry J Housh, Anthony J Bull, Kyle T Ebersole
    Abstract:

    Abstract The purpose of this investigation was to determine the relationships for mechanomyographic (MMG) amplitude, MMG mean Power Frequency (MPF), electromyographic (EMG) amplitude, and EMG MPF versus Power output during incremental cycle ergometry. Seventeen adults volunteered to perform an incremental test to exhaustion on a cycle ergometer. The test began at 50 W and the Power output was increased by 30 W every 2 min until the subject could no longer maintain 70 rev min −1 . The MMG and EMG signals were recorded simultaneously from the vastus lateralis during the final 10 s of each Power output and analyzed. MMG amplitude, MMG MPF, EMG amplitude, EMG MPF, and Power output were normalized as a percentage of the maximal value from the cycle ergometer test. Polynomial regression analyses indicated that MMG amplitude increased ( P P >0.05) in MMG MPF. EMG amplitude and MPF were fit best ( P

Jared W Coburn - One of the best experts on this subject based on the ideXlab platform.

  • comparison of mechanomyographic amplitude and mean Power Frequency for the rectus femoris muscle cycle versus knee extensor ergometry
    Journal of Neuroscience Methods, 2009
    Co-Authors: Moh H Malek, Jared W Coburn, Vince Tedjasaputra
    Abstract:

    The purpose of this study was to compare the mechanomyographic (MMG) amplitude and mean Power Frequency (MPF) versus Power output relationships for the rectus femoris (RF) muscle during incremental cycle (CE) and knee-extensor (KE) ergometry in the same subjects. Eight men performed incremental CE and KE tests to exhaustion while the MMG signal was recorded from the RF muscle. Polynomial regression analyses on the composite and subject-by-subject basis indicated that the relationship between MMG amplitude versus Power output was best-fit with a linear model for the composite data and each subject for the KE test, whereas the relationship was best-fit with a linear model for the composite data, but either linear, quadratic, or cubic for the CE test. In addition, there were no consistent patterns of responses for either the CE or KE test for MMG MPF. These results suggest that KE rather than traditional CE exercise may be an optimal mode of examining MMG amplitude for the RF muscle.

  • the effects of innervation zone on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir
    Abstract:

    Abstract The purpose of this study was to examine the effects of electrode placements over the innervation zone (IZ), as well as proximal and distal to the IZ, on the patterns for the absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) versus Power output relationships during incremental cycle ergometry. Fifteen men [mean ± S.D. age = 24.3 ± 2.4 years; V ˙ O 2 max = 47.3 ± 4.9 ml k g − 1 mi n − 1 ] performed incremental cycle ergometry tests to exhaustion. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed on the vastus lateralis (VL) muscle over the IZ, as well as proximal and distal to the IZ. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (μVrms and %max) and MPF (Hz and %max) versus Power output (%max) for each subject at the three electrode placement sites. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three sites for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression analyses revealed that the best fit model for each site for the absolute and normalized EMG amplitude versus Power output relationship was linear for 11 subjects and quadratic for 2 subjects. The remaining two subjects exhibited both linear and quadratic patterns that were site-dependent. For EMG MPF, 10 subjects exhibited significant relationships (linear and/or quadratic) across Power outputs for at least one site. In addition, there were significant ( P  0.05) mean differences between the electrode placement sites for absolute EMG amplitude, but not absolute EMG MPF at 80, 110, 140, and 170 W. There were no significant ( P >  0.05) mean differences, however, between the three sites for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. These findings indicated that the placement of bipolar electrodes over the IZ, as well as proximal and distal to the IZ, had no effect on the pattern of the normalized EMG amplitude versus Power output relationship or the mean normalized EMG amplitude and MPF values. Thus, during cycle ergometry, normalized EMG amplitude values (but not absolute values) can be compared between studies that have utilized various electrode placement sites on the VL.

  • the effects of innervation zone on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Travis W Beck, Terry J Housh
    Abstract:

    Abstract The purpose of this study was to examine the effects of electrode placements over the innervation zone (IZ), as well as proximal and distal to the IZ, on the patterns for the absolute and normalized electromyographic (EMG) amplitude and mean Power Frequency (MPF) versus Power output relationships during incremental cycle ergometry. Fifteen men [mean ± S.D. age = 24.3 ± 2.4 years; V ˙ O 2 max = 47.3 ± 4.9 ml k g − 1 mi n − 1 ] performed incremental cycle ergometry tests to exhaustion. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed on the vastus lateralis (VL) muscle over the IZ, as well as proximal and distal to the IZ. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (μVrms and %max) and MPF (Hz and %max) versus Power output (%max) for each subject at the three electrode placement sites. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three sites for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression analyses revealed that the best fit model for each site for the absolute and normalized EMG amplitude versus Power output relationship was linear for 11 subjects and quadratic for 2 subjects. The remaining two subjects exhibited both linear and quadratic patterns that were site-dependent. For EMG MPF, 10 subjects exhibited significant relationships (linear and/or quadratic) across Power outputs for at least one site. In addition, there were significant (P   0.05) mean differences, however, between the three sites for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. These findings indicated that the placement of bipolar electrodes over the IZ, as well as proximal and distal to the IZ, had no effect on the pattern of the normalized EMG amplitude versus Power output relationship or the mean normalized EMG amplitude and MPF values. Thus, during cycle ergometry, normalized EMG amplitude values (but not absolute values) can be compared between studies that have utilized various electrode placement sites on the VL.

  • the effects of interelectrode distance on electromyographic amplitude and mean Power Frequency during incremental cycle ergometry
    Journal of Neuroscience Methods, 2006
    Co-Authors: Moh H Malek, Jared W Coburn, Joseph P. Weir, Terry J Housh, Richard J Schmidt, Travis W Beck
    Abstract:

    The purpose of this study was to examine the effects of interelectrode distance (IED) on the relationships of absolute and normalized EMG amplitude and mean Power Frequency (MPF) versus Power output during incremental cycle ergometry. Eleven adults (mean +/- S.D. age = 24.2 +/- 2.6 y; V(O2max) = 49.4 +/- 8.3 ml kg(-1) min(-1)) performed incremental cycle ergometry tests. Surface EMG signals were recorded simultaneously from bipolar electrode arrangements placed over the VL muscle with IEDs of 20, 40, and 60 mm. Polynomial regression analyses were used to describe the relationships for absolute and normalized EMG amplitude (muV(rms) and % max) and MPF (Hz and % max) versus Power output (%max) for each subject at the three IEDs. In addition, separate one-way repeated measures ANOVAs were used to examine mean differences between the three IEDs for absolute and normalized EMG amplitude and MPF at Power outputs of 80, 110, 140, and 170 W. The results of the polynomial regression revealed that the best fit model for each IED for the absolute and normalized EMG amplitude was linear for six of the 11 subjects and quadratic for five of the subjects. For EMG MPF, four of the 11 subjects exhibited significant relationships (linear or quadratic) across Power outputs for at least one IED. The one-way repeated measures ANOVAs revealed significant mean differences between the IEDs for absolute EMG amplitude and MPF at 80, 110, 140, and 170 W. There were no significant mean differences, however, between the IEDs for normalized EMG amplitude or MPF at 80, 110, 140, and 170 W. The results of the study indicated that there were no consistent patterns of responses between individual subjects for EMG amplitude or MPF versus Power output relationships for IEDs of 20, 40, and 60 mm during incremental cycle ergometry. The current findings supported the process of normalization for EMG amplitude and MPF data obtained during cycle ergometry when comparisons are made for different IEDs.

  • mechanomyographic amplitude and mean Power Frequency versus torque relationships during isokinetic and isometric muscle actions of the biceps brachii
    Journal of Electromyography and Kinesiology, 2004
    Co-Authors: Travis W Beck, Glen O Johnson, Jared W Coburn, Joseph P. Weir, Terry J Housh, Joel T Cramer, Moh H Malek
    Abstract:

    Abstract The purpose of this investigation was to determine the mechanomyographic (MMG) amplitude and mean Power Frequency (MPF) versus torque (or force) relationships during isokinetic and isometric muscle actions of the biceps brachii. Ten adults (mean±SD age=21.6±1.7 years) performed submaximal to maximal isokinetic and isometric muscle actions of the dominant forearm flexors. Following determination of isokinetic peak torque (PT) and the isometric maximum voluntary contraction (MVC), the subjects randomly performed submaximal step muscle actions in 10% increments from 10% to 90% PT and MVC. Polynomial regression analyses indicated that MMG amplitude increased linearly with torque during both the isokinetic ( r 2 =0.982) and isometric ( r 2 =0.956) muscle actions. From 80% to 100% of isometric MVC, however, MMG amplitude appeared to plateau. Cubic models provided the best fit for the MMG MPF versus isokinetic ( R 2 =0.786) and isometric ( R 2 =0.940) torque relationships, although no significant increase in MMG MPF was found from 10% to 100% of isokinetic PT. For the isometric muscle actions, however, MMG MPF remained relatively stable from 10% to 50% MVC, increased from 50% to 80% MVC, and decreased from 80% to 100% MVC. The results demonstrated differences in the MMG amplitude and MPF versus torque relationships between the isokinetic and isometric muscle actions. These findings suggested that the time and Frequency domains of the MMG signal may be useful for describing the unique motor control strategies that modulate dynamic versus isometric torque production.