25 results on '"Schmidt, Richard J."'
Search Results
2. Evaluating pediatric intensive care unit utilization after tonsillectomy
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Vandjelovic, Nathan D., Briddell, Jenna W., Crippen, Meghan M., and Schmidt, Richard J.
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- 2020
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3. Effects of anatabine and unilateral maximal eccentric isokinetic muscle actions on serum markers of muscle damage and inflammation
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Jenkins, Nathaniel D.M., Housh, Terry J., Cochrane, Kristen C., Bergstrom, Haley C., Traylor, Daniel A., Lewis, Robert W., Jr., Buckner, Samuel L., Schmidt, Richard J., Johnson, Glen O., and Cramer, Joel T.
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- 2014
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4. Comparing electromyographic and mechanomyographic frequency-based fatigue thresholds to critical torque during isometric forearm flexion
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Hendrix, C. Russell, Housh, Terry J., Camic, Clayton L., Zuniga, Jorge M., Johnson, Glen O., and Schmidt, Richard J.
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- 2010
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5. A mechanomyographic frequency-based fatigue threshold test
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Hendrix, C. Russell, Housh, Terry J., Zuniga, Jorge M., Camic, Clayton L., Mielke, Michelle, Johnson, Glen O., and Schmidt, Richard J.
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- 2010
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6. The effects of electrode orientation on electromyographic amplitude and mean power frequency during cycle ergometry
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Zuniga, Jorge M., Housh, Terry J., Hendrix, C. Russell, Camic, Clayton L., Mielke, Michelle, Schmidt, Richard J., and Johnson, Glen O.
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- 2009
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7. A new EMG frequency-based fatigue threshold test
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Hendrix, C. Russell, Housh, Terry J., Johnson, Glen O., Mielke, Michelle, Camic, Clayton L., Zuniga, Jorge M., and Schmidt, Richard J.
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- 2009
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8. The effects of interelectrode distance on electromyographic amplitude and mean power frequency during incremental cycle ergometry
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Malek, Moh H., Housh, Terry J., Coburn, Jared W., Weir, Joseph P., Schmidt, Richard J., and Beck, Travis W.
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- 2006
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9. A two-dimensional ideal gas finite element
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Schmidt, Richard J. and Fulton, Keith R.
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- 2001
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10. Response to Letter to the Editor regarding “Postoperative nonsteroidal anti-inflammatory drugs and risk of bleeding in pediatric intracapsular tonsillectomy”
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D'Souza, Jill N., Schmidt, Richard J., Xie, Li, Adelman, Julie P., and Nardone, Heather C.
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- 2015
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11. Postoperative nonsteroidal anti-inflammatory drugs and risk of bleeding in pediatric intracapsular tonsillectomy.
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D'Souza, Jill N., Schmidt, Richard J., Xie, Li, Adelman, Julie P., and Nardone, Heather C.
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NONSTEROIDAL anti-inflammatory agents , *SURGICAL complications , *HEMORRHAGE risk factors , *TONSILLECTOMY , *HEALTH outcome assessment - Abstract
Objectives In light of current FDA guidelines on opioid use in children, we sought to determine the risk of post-tonsillectomy hemorrhage (PTH) in children who received ibuprofen with acetaminophen versus those who received narcotic with acetaminophen for postoperative pain control. Methods This was an IRB-approved retrospective chart review of patients at a tertiary-care pediatric center. The medical records of 449 children who received acetaminophen and ibuprofen following intracapsular tonsillectomy with or without adenoidectomy were reviewed (NSAID group) and compared with medical records of 1731 children who underwent intracapsular tonsillectomy and received acetaminophen with codeine or hydrocodone with acetaminophen postoperatively (narcotic group). Main outcome measure was the incidence of PTH requiring return to the operating room. Secondary outcome measures included incidence of primary PTH, secondary PTH, and postoperative evaluation in the emergency department or readmission for pain and/or dehydration. Results Incidence of PTH requiring return to the operating room was higher in the NSAID group (1.6%) compared with the narcotic group (0.5%), P = 0.01. Incidence of primary PTH was significantly higher in the NSAID group (2%) versus the narcotic group (0.12%), P < 0.0001. Incidence of secondary PTH was 3.8% in the NSAID group and 1.1% in the narcotic group ( P < 0.0001). Conclusion Use of ibuprofen after intracapsular tonsillectomy in children is associated with statistically significant increase in PTH requiring return to the operating room, as well as an increase in overall rates of both primary and secondary PTH. Ibuprofen provides pain control that is at least equivalent to narcotic and is not associated with respiratory depression. Further study of ibuprofen use in the post-tonsillectomy patient is warranted. [ABSTRACT FROM AUTHOR]
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- 2015
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12. Laryngotracheal reconstruction in infants and children: Are single-stage anterior and posterior grafts a reliable intervention at all pediatric hospitals?
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Schmidt, Richard J., Shah, Gopi, Sobin, Lindsay, and Reilly, James S.
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CHILDREN'S hospitals , *CARTILAGE , *JUVENILE diseases , *RETROSPECTIVE studies , *ARTERIAL stenosis , *HEALTH outcome assessment , *AIRWAY (Anatomy) - Abstract
Abstract: Objective: To review outcomes of pediatric laryngotracheal stenosis treated by single-stage laryngotracheal reconstruction with anterior and posterior cartilage grafts and compare decannulation rate for single-stage laryngotracheal reconstruction with rates published at larger (>200 beds) pediatric tertiary care hospitals. Methods: A 4-year retrospective chart review (2004–2008) of all patients undergoing procedures coded with 2008 CPT codes 31582 (laryngoplasty for laryngeal stenosis with graft or core mold, including tracheotomy) and 31587 (laryngoplasty, cricoid split) for a pediatric, tertiary-care hospital. Interventions were single-stage laryngotracheal reconstruction with anterior and posterior cartilage grafts, and the main outcome measure was the decannulation rate after single-stage laryngotracheal reconstruction. Results: We identified 44 patients with subglottic stenosis, of whom 13 underwent single-stage laryngotracheal reconstruction with anterior and posterior cartilage grafts. The mean age at surgery was 2.2 years (range, 5 months to 4 years). Twelve of 13 children had Cotton-Myer grade III stenosis. Ninety-two percent (12 of 13) of children remain decannulated. The mean follow up was 52 months. Conclusions: Single-stage laryngotracheal reconstruction with anterior and posterior cartilage grafts appears to be a safe and effective technique for managing patients with high-grade subglottic stenosis at intermediate size children''s hospitals. Our overall decannulation rate of 92% compares favorably to that reported in the literature (84–96%). [Copyright &y& Elsevier]
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- 2011
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13. The effect of epoch length on time and frequency domain parameters of electromyographic and mechanomyographic signals.
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Keller, Joshua L., Housh, Terry J., Camic, Clayton L., Bergstrom, Haley C., Smith, Doug B., Smith, Cory M., Hill, Ethan C., Schmidt, Richard J., Johnson, Glen O., and Zuniga, Jorge M.
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ELECTROMYOGRAPHY , *SIGNAL processing , *ISOMETRIC exercise , *EXERCISE intensity , *PARAMETER estimation , *SKELETAL muscle physiology , *KINEMATICS , *MUSCLE contraction , *TIME , *TORQUE , *PHYSIOLOGY - Abstract
The selection of epoch lengths affects the time and frequency resolution of electromyographic (EMG) and mechanomyographic (MMG) signals, as well as decisions regarding the signal processing techniques to use for determining the power density spectrum. No previous studies, however, have examined the effects of epoch length on parameters of the MMG signal. The purpose of this study was to examine the differences between epoch lengths for EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF from the VL and VM muscles during MVIC muscle actions as well as at each 10% of the time to exhaustion (TTE) during a continuous isometric muscle action of the leg extensors at 50% of MVIC. During the MVIC trial, there were no significant (p > 0.05) differences between epoch lengths (0.25, 0.50, 1.00, and 2.00-s) for mean absolute values for any of the EMG or MMG parameters. During the submaximal, sustained muscle action, however, absolute MMG amplitude and MMG MPF were affected by the length of epoch. All epoch related differences were eliminated by normalizing the absolute values to MVIC. These findings supported normalizing EMG and MMG parameter values to MVIC and utilizing epoch lengths that ranged from 0.25 to 2.00-s. [ABSTRACT FROM AUTHOR]
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- 2018
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14. Are there mode-specific and fatigue-related electromechanical delay responses for maximal isokinetic and isometric muscle actions?
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Smith, Cory M., Housh, Terry J., Hill, Ethan C., Keller, Joshua L., Johnson, Glen O., and Schmidt, Richard J.
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ELECTROMECHANICAL technology , *MUSCLE fatigue , *ISOKINETIC exercise , *MUSCLE physiology , *ELECTROMYOGRAPHY , *QUADRICEPS muscle physiology , *SKELETAL muscle physiology , *EXERCISE , *MUSCLE contraction - Abstract
This study used a combined electromyographic, mechanomyographic, and force approach to identify electromechanical delay (EMD) from the onsets of the electromyographic to force signals (EMDE-F), onsets of the electromyographic to mechanomyogrpahic signals (EMDE-M), and onsets of mechanomyographic to force signals (EMDM-F). The purposes of the current study were to examine: (1) differences in EMDE-M, EMDM-F, and EMDE-F from the vastus lateralis between maximal isokinetic and maximal concentric isometric leg extensions; and (2) the effects of fatigue and recovery on EMDE-M, EMDM-F, and EMDE-F. These EMD measures were obtained from twelve men during maximal concentric isokinetic and isometric leg extensions pretest, posttest, and after 3-min and 5-min of recovery from 25 maximal isokinetic leg extensions at 60°s-1. The results indicated no differences between maximal isokinetic and isometric muscle actions for EMDE-M, EMDM-F, or EMDE-F during the pretest, posttest, 3-min recovery, and 5-min recovery measurements. These findings support the comparison of voluntary EMD measures between studies with different modes of exercise as long as the methodology for the determination of EMD are consistent. There were, however, fatigue-induced pretest to posttest increases in EMDE-M, EMDM-F, and EMDE-F which remained elongated after 3-min of recovery, but returned to pretest values after 5-min of recovery. [ABSTRACT FROM AUTHOR]
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- 2017
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15. Dynamic versus isometric electromechanical delay in non-fatigued and fatigued muscle: A combined electromyographic, mechanomyographic, and force approach.
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Smith, Cory M., Housh, Terry J., Hill, Ethan C., Johnson, Glen O., and Schmidt, Richard J.
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ELECTROMYOGRAPHY , *MUSCLE fatigue , *MUSCLE contraction , *BIOMECHANICS , *ISOMETRIC exercise , *QUADRICEPS muscle physiology , *REACTION time , *TORQUE - Abstract
This study used a combined electromyographic, mechanomyographic, and force approach to identify electromechanical delay (EMD) from the onsets of the electromyographic to force signals (EMDE-F), onsets of the electromyographic to mechanomyogrpahic signals (EMDE-M), and onsets of mechanomyographic to force signals (EMDM-F). The purposes of the current study were to examine: (1) the differences in EMDE-F, EMDE-M, and EMDM-F from the vastus lateralis during maximal, voluntary dynamic (1 repetition maximum [1-RM]) and isometric (maximal voluntary isometric contraction [MVIC]) muscle actions; and (2) the effects of fatigue on EMDE-F, EMDM-F, and EMDE-M. Ten men performed pretest and posttest 1-RM and MVIC leg extension muscle actions. The fatiguing workbout consisted of 70% 1-RM dynamic constant external resistance leg extension muscle actions to failure. The results indicated that there were no significant differences between 1-RM and MVIC EMDE-F, EMDE-M, or EMDM-F. There were, however, significant fatigue-induced increases in EMDE-F (94% and 63%), EMDE-M (107%), and EMDM-F (63%) for both the 1-RM and MVIC measurements. Therefore, these findings demonstrated the effects of fatigue on EMD measures and supported comparisons among studies which examined dynamic or isometric EMD measures from the vastus lateralis using a combined electromyographic, mechanomyographic, and force approach. [ABSTRACT FROM AUTHOR]
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- 2017
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16. Effects of the innervation zone on the time and frequency domain parameters of the surface electromyographic signal.
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Smith, Cory M., Housh, Terry J., Herda, Trent J., Zuniga, Jorge M., Ryan, Eric D., Camic, Clayton L., Bergstrom, Haley C., Smith, Doug B., Weir, Joseph P., Cramer, Joel T., Hill, Ethan C., Cochrane, Kristen C., Jenkins, Nathaniel D.M., Schmidt, Richard J., and Johnson, Glen O.
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ELECTROMYOGRAPHY , *INNERVATION , *FREQUENCY-domain analysis , *MUSCLE physiology , *PARAMETERS (Statistics) , *ISOMETRIC exercise , *EXERCISE intensity - Abstract
The purposes of the present study were to examine the effects of electrode placements over, proximal, and distal to the innervation zone (IZ) on electromyographic (EMG) amplitude (RMS) and frequency (MPF) responses during: (1) a maximal voluntary isometric contraction (MVIC), and; (2) a sustained, submaximal isometric muscle action. A linear array was used to record EMG signals from the vastus lateralis over the IZ, 30 mm proximal, and 30 mm distal to the IZ during an MVIC and a sustained isometric muscle action of the leg extensors at 50% MVIC. During the MVIC, lower EMG RMS ( p > 0.05) and greater EMG MPF ( p < 0.05) values were recorded over the IZ compared to away from the IZ, however, no differences in slope coefficients for the EMG RMS and MPF versus time relationships over, proximal, and distal to the IZ occurred. Thus, the results of the present study indicated that during an MVIC, EMG RMS and MPF values recorded over the IZ are not comparable to those away from the IZ. However, the rates of fatigue-induced changes in EMG RMS and MPF during sustained, submaximal isometric muscle actions of the leg extensors were the same regardless of the electrode placement locations relative to the IZ. [ABSTRACT FROM AUTHOR]
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- 2015
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17. Reliability and relationships among handgrip strength, leg extensor strength and power, and balance in older men.
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Jenkins, Nathaniel D.M., Buckner, Samuel L., Bergstrom, Haley C., Cochrane, Kristen C., Goldsmith, Jacob A., Housh, Terry J., Johnson, Glen O., Schmidt, Richard J., and Cramer, Joel T.
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MUSCLE strength , *EXTENSOR muscles , *OLDER people , *ISOKINETIC exercise , *STATISTICAL correlation - Abstract
Purpose To quantify the reliability of isometric leg extension torque (LE MVC ), rate of torque development (LE RTD ), isometric handgrip force (HG MVC ) and RFD (HG RFD ), isokinetic leg extension torque and power at 1.05 rad·s − 1 and 3.14 rad·s − 1 ; and explore relationships among strength, power, and balance in older men. Methods Sixteen older men completed 3 isometric handgrips, 3 isometric leg extensions, and 3 isokinetic leg extensions at 1.05 rad·s − 1 and 3.14 rad·s − 1 during two visits. Intraclass correlation coefficients (ICCs), ICC confidence intervals (95% CI), coefficients of variation (CVs), and Pearson correlation coefficients were calculated. Results LE RTD demonstrated no reliability. The CVs for LE RTD and HG RFD were ≤ 23.26%. HG MVC wasn't related to leg extension torque or power, or balance (r = 0.14–0.47; p > 0.05). However, moderate to strong relationships were found among isokinetic leg extension torque at 1.05 rad·s − 1 and 3.14 rad·s − 1 , leg extension mean power at 1.05 rad·s − 1 , and functional reach (r = 0.51–0.95; p ≤ 0.05). Conclusions LE RTD and HG RFD weren't reliable and shouldn't be used as outcome variables in older men. Handgrip strength may not be an appropriate surrogate for lower body strength, power, or balance. Instead, perhaps handgrip strength should only be used to describe upper body strength or functionality, which may compliment isokinetic assessments of lower body strength, which were reliable and related to balance. [ABSTRACT FROM AUTHOR]
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- 2014
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18. Age-related differences in rates of torque development and rise in EMG are eliminated by normalization.
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Jenkins, Nathaniel D.M., Buckner, Samuel L., Cochrane, Kristen C., Bergstrom, Haley C., Palmer, Ty B., Johnson, Glen O., Schmidt, Richard J., Housh, Terry J., and Cramer, Joel T.
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ELECTROMYOGRAPHY , *SARCOPENIA , *MUSCLE strength , *NEUROMUSCULAR system , *TORQUE , *AGE factors in disease , *DISABILITY rights movement - Abstract
The purpose of this study was to compare the voluntary and evoked, absolute and normalized leg extension rates of torque development (RTD) and rates of rise in electromyography (RER) during commonly reported time intervals in young and old men. Fourteen young men (21.9 ± 3.2 years) and 16 older men (72.3 ± 7.3 years) completed three evoked and three voluntary isometric leg extension muscle actions to quantify absolute voluntary (peak, 30, 50, 100, and 200 ms) and evoked (peak, 30, 50, and 100 ms) RTD and RER. All RTD values were normalized (nRTD) to peak torque, while RER values were normalized (nRER) to peak-to-peak M-wave amplitude (M PP ). Absolute voluntary RTDs and RERs were 58–122% and 70–76% greater (p ≤ 0.05) for the young men, respectively. However, there were no age-related differences (p > 0.05) for voluntary nRTDs, absolute and normalized evoked RTDs, or voluntary nRER. M PP and evoked RER and nRER were greater (p ≤ 0.05) for the young men. In addition, voluntary RTD was more reliable in the young than the older men. Normalizing RTD to peak torque and RER to M-wave amplitude eliminated the age-related differences and suggested that the age-related declines in RTD and RER were a result of reduced muscle strength and M-wave amplitude, respectively. Therefore, our findings questioned the value of RTD and RER measurements in the various time intervals for explaining sarcopenia and suggested that maximal strength and M-wave amplitude may be sufficient. [ABSTRACT FROM AUTHOR]
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- 2014
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19. Mechanomyographic and metabolic responses during continuous cycle ergometry at critical power from the 3-min all-out test
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Bergstrom, Haley C., Housh, Terry J., Zuniga, Jorge M., Traylor, Daniel A., Lewis, Robert W., Camic, Clayton L., Schmidt, Richard J., and Johnson, Glen O.
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ELECTROMYOGRAPHY , *METABOLISM , *ERGOMETRY , *OXYGEN consumption , *HEART beat , *DYNAMOMETER - Abstract
Abstract: There are limited data regarding metabolic responses during continuous exhaustive rides at critical power (CP) from the 3-min all-out test. In addition, no previous studies have examined the mechanomyographic (MMG) responses at CP from the 3-min all-out test. Therefore, this study examined the metabolic and MMG responses during continuous exercise at CP determined from the 3-min all-out test. Nine college-aged females (mean±SD: age 23.0±3.6yrs) performed an incremental test to exhaustion on a cycle ergometer to identify the gas exchange threshold, peak oxygen consumption rate ( peak) and heart rate peak (HR peak). The , HR, MMG amplitude and mean power frequency (MPF) responses were examined during continuous rides to exhaustion at CP (81±6% peak power). There were significant increases in and HR over time and there was no significant difference between peak and at exhaustion or HR peak and HR at exhaustion. There were, however, no significant changes for MMG amplitude or MPF over time. Therefore, the current findings suggested that the 3-min all-out test overestimated CP and the demarcation between the heavy and severe intensity domains. Specifically, the and HR responses did not reach a steady state and were driven to peak values. Furthermore, the non-significant change in MMG amplitude and MPF were consistent with the responses observed at fatiguing power outputs (i.e., >80% peak power). [Copyright &y& Elsevier]
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- 2013
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20. Electromyographic and mechanomyographic responses across repeated maximal isometric and concentric muscle actions of the leg extensors
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Camic, Clayton L., Housh, Terry J., Zuniga, Jorge M., Russell Hendrix, C., Bergstrom, Haley C., Traylor, Daniel A., Schmidt, Richard J., and Johnson, Glen O.
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ELECTROMYOGRAPHY , *ISOMETRIC exercise , *MUSCLE contraction , *LEG physiology , *TORQUE , *MUSCLE physiology , *PERFORMANCE evaluation - Abstract
Abstract: The purpose of the present study was to examine the patterns of responses for torque, electromyographic (EMG) amplitude, EMG mean power frequency (MPF), mechanomyographic (MMG) amplitude, and MMG MPF across 30 repeated maximal isometric (ISO) and concentric (CON) muscle actions of the leg extensors. Twelve female subjects (21.1±1.4yrs; 63.3±7.4kg) performed ISO and CON fatigue protocols with EMG and MMG signals recorded from the vastus lateralis. The relationships for torque, EMG amplitude, EMG MPF, MMG amplitude, and MMG MPF versus repetition number were examined using polynomial regression. The results indicated there were decreases (p <0.05) across the ISO muscle actions for torque (r 2 =0.95), EMG amplitude (R 2 =0.44), EMG MPF (r 2 =0.62), and MMG MPF (r 2 =0.48), but no change in MMG amplitude (r 2 =0.07). In addition, there were decreases across the CON muscle actions for torque (R 2 =0.97), EMG amplitude (R 2 =0.46), EMG MPF (R 2 =0.86), MMG amplitude (R 2 =0.44), and MMG MPF (R 2 =0.80). Thus, the current findings suggested that the mechanisms of fatigue and motor control strategies used to modulate torque production were similar between maximal ISO and CON muscle actions. [Copyright &y& Elsevier]
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- 2013
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21. The effects of skinfold thicknesses and innervation zone on the mechanomyographic signal during cycle ergometry
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Zuniga, Jorge M., Housh, Terry J., Camic, Clayton L., Russell Hendrix, C., Bergstrom, Haley C., Schmidt, Richard J., and Johnson, Glen O.
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SKINFOLD thickness , *INNERVATION , *ELECTROMYOGRAPHY , *ERGOMETRY , *VASTUS lateralis , *ACCELEROMETERS , *EXERCISE tests , *REGRESSION analysis - Abstract
Abstract: The purpose of this study was to examine the effects of skinfold (SF) thicknesses at four locations on the vastus lateralis (VL) muscle and the placement of accelerometers relative to the innervation zone (IZ) on the mechanomyographic (MMG) amplitude and mean power frequency (MPF) responses during incremental cycle ergometry. Twenty adults (age±SD=23.8±3.0years) participated in the investigation. The MMG signals were detected during incremental cycle ergometry using four accelerometers placed on the right VL. Prior to the cycle ergometer test, SF thicknesses were measured. Simple linear regression analyses and one-way repeated measures analyses of variance (ANOVAs) were performed. The present study found that only 10% of the regression analyses and mean comparisons were significant (p <0.05). Furthermore, the accelerometer placed at the most proximal site (Prox 2) had significantly greater MMG amplitude and MMG MPF than accelerometers placed at more distal sites (Prox 1, Over IZ, and Dist). There were no significant differences, however, in SF thickness between accelerometer placement sites. In addition, the IZ had no effect on MMG amplitude and little effect on MMG MPF values. The results of the present study indicated that the SF thickness values and IZ did not affect the MMG signal. [Copyright &y& Elsevier]
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- 2011
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22. The influence of the muscle fiber pennation angle and innervation zone on the identification of neuromuscular fatigue during cycle ergometry
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Camic, Clayton L., Housh, Terry J., Hendrix, C. Russell, Zuniga, Jorge M., Bergstrom, Haley C., Schmidt, Richard J., and Johnson, Glen O.
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BIOMECHANICS , *INNERVATION , *NEUROMUSCULAR system , *FATIGUE (Physiology) , *CYCLING , *ERGOMETRY , *ELECTROMYOGRAPHY - Abstract
Abstract: The purpose of the present investigation was to compare the electromyographic (EMG) responses and the estimated physical working capacity at the fatigue threshold (PWCFT) values recorded from electrode arrangements placed: (1) parallel to the muscle fiber pennation angle (MFPA), (2) parallel to the long axis of the femur, and (3) over the innervation zone (IZ) during incremental cycle ergometry. Thirteen college-aged males and females (mean age±SD=22.4±3.4years) performed an incremental test to exhaustion on a cycle ergometer. A linear electrode array was utilized to determine the MFPA and location of the IZ of the vastus lateralis (VL). For determination of the PWCFT values, EMG signals were recorded from three bipolar electrode arrangements at different locations over the VL. The results of a one-way repeated measures ANOVA indicated there were no significant (p <0.05) mean differences in PWCFT values among the electrode arrangements (parallel to the MFPA=190±36W; parallel to the long axis of the femur=194±40W; and over the IZ=199±51W) or the EMG amplitude and MPF values at the common power outputs. There were also significant correlations (r =0.75–0.91) among the three electrode arrangements for PWCFT values. These findings suggested that the PWCFT, like absolute EMG amplitude and MPF, is robust to the influence of electrode placement over the IZ as well as the orientation with respect to the MFPA during cycle ergometry. [ABSTRACT FROM AUTHOR]
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- 2011
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23. The effects of accelerometer placement on mechanomyographic amplitude and mean power frequency during cycle ergometry
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Zuniga, Jorge M., Housh, Terry J., Camic, Clayton L., Hendrix, C. Russell, Mielke, Michelle, Schmidt, Richard J., and Johnson, Glen O.
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ERGOMETRY , *ACCELEROMETERS , *EXERCISE physiology , *VASTUS lateralis , *PUBLIC health , *MUSCLE contraction , *ELECTROMYOGRAPHY - Abstract
Abstract: The purposes of this study were threefold: (1) to compare the power output related patterns of absolute and normalized MMG amplitude and MPF responses for proximal and distal accelerometer placements on the vastus lateralis (VL) muscle during incremental cycle ergometry; (2) to examine the influence of accelerometer placements on mean absolute MMG amplitude and MPF values; and (3) to determine the effects of normalization on mean MMG amplitude and MPF values from proximal and distal accelerometer placements. Fifteen adults (10 men and 5 women; mean±SD age=23.9±3.1years) performed incremental cycle ergometry tests to exhaustion. Two accelerometers were placed proximal and distal on the VL muscle. Paired t-tests indicated that absolute MMG amplitude values for the proximal accelerometer were greater (p <0.05) than the distal accelerometer at all power outputs. The normalized MMG amplitude also had greater values for the proximal accelerometer at all power outputs, except 50W. There were no differences, however, between proximal and distal accelerometers for absolute MMG MPF, except at 75W, and normalization eliminated this difference. Twenty-seven percent of the subjects exhibited different power output related patterns of responses between accelerometer placements for MMG amplitude and 47% exhibited different patterns for MPF. These findings indicated that normalization did not eliminate the influence of accelerometer placement on MMG amplitude and highlighted the importance of standardizing accelerometer placements to compare MMG values during cycle ergometry. [Copyright &y& Elsevier]
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- 2010
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24. The role of oxidised regenerated cellulose/collagen in chronic wound repair and its potential mechanism of action
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Cullen, Breda, Watt, Paul W., Lundqvist, Charlotte, Silcock, Derek, Schmidt, Richard J., Bogan, Declan, and Light, Nicholas D.
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PROTEOLYTIC enzymes , *FREE radicals , *GROWTH factors - Abstract
Normal wound healing is a carefully controlled balance of destructive processes necessary to remove damaged tissue and repair processes which lead to new tissue formation. Proteases and growth factors play a pivotal role in regulating this balance, and if disrupted in favour of degradation then delayed healing ensues; a trait of chronic wounds. Whilst there are many types of chronic wounds, biochemically they are thought to be similar in that they are characterised by a prolonged inflammatory phase, which results in elevated levels of proteases and diminished growth factor activity. This increase in proteolytic activity and subsequent degradation of growth factors is thought to contribute to the net tissue loss associated with these chronic wounds.In this study, we describe a new wound treatment, comprising oxidised regenerated cellulose and collagen (ORC/collagen), which can redress this imbalance and modify the chronic wound environment. We demonstrate that ORC/collagen can inactivate potentially harmful factors such as proteases, oxygen free radicals and excess metal ions present in chronic wound fluid, whilst simultaneously protecting positive factors such as growth factors and delivering them back to the wound.These characteristics suggest a beneficial role for this material in helping to re-balance the chronic wound environment and therefore promote healing. [Copyright &y& Elsevier]
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- 2002
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25. Performance fatigability and neuromuscular responses for bilateral versus unilateral leg extensions in women.
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Anders, John Paul V., Keller, Joshua L., Smith, Cory M., Hill, Ethan C., Neltner, Tyler J., Housh, Terry J., Schmidt, Richard J., and Johnson, Glen O.
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ISOKINETIC exercise , *ELECTROMYOGRAPHY , *BODY mass index , *MEDICAL records , *SIGNAL processing , *LEG physiology , *SKELETAL muscle physiology , *TORQUE , *MUSCLE contraction , *CEREBRAL dominance , *MUSCLE fatigue , *ROUTINE diagnostic tests - Abstract
The purpose of this study was to compare isokinetic peak torque and the patterns of responses for electromyographic (EMG) and mechanomyographic (MMG), amplitude (AMP) and mean power frequency (MPF) for bilateral (BL) versus unilateral (UL), maximal, isokinetic leg extensions. Eleven recreationally trained women (Mean ± SD: age 22.9 ± 0.9 yrs; body mass 60.5 ± 10.1 kg; height 167.2 ± 6.4 cm) performed 50 maximal, BL and UL isokinetic leg extensions at 60° s-1 on separate days. Electromyographic and MMG signals from the vastus lateralis of the nondominant leg were recorded. Five separate 2 (Condition [BL and UL]) × 10 (Repetitions [5-50]) repeated measures ANOVAs were performed to examine normalized EMG AMP, EMG MPF, MMG AMP, MMG MPF, and isokinetic torque. The results indicated no significant interactions or main effects for EMG AMP and MMG AMP. There were significant interactions for normalized isokinetic peak torque (p < 0.001, η2p = 0.493) and MMG MPF (p = 0.003, η2p = 0.234). For EMG MPF, there was no significant interaction, but significant main effects for Condition (p = 0.003, η2p = 0.607) and Repetitions (p < 0.001, η2p = 0.805). The current findings demonstrated greater performance fatigability for UL than BL leg extensions. Both modalities exhibited similar patterns of neuromuscular responses that were consistent with the Muscular Wisdom hypothesis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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