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- Biomechanics (16)
- Aging (15)
- Muscle fatigue (13)
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- Exercise (8)
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Articles 91 - 110 of 110
Full-Text Articles in Sports Sciences
Age And Load Compliance Alter Time To Task Failure For A Submaximal Fatiguing Contraction With The Lower Leg, Erin E. Griffith, Tejin Yoon, Sandra K. Hunter
Age And Load Compliance Alter Time To Task Failure For A Submaximal Fatiguing Contraction With The Lower Leg, Erin E. Griffith, Tejin Yoon, Sandra K. Hunter
Exercise Science Faculty Research and Publications
The purpose of this study was to compare the time to failure and muscle activation of young and old adults for a sustained isometric submaximal contraction with the dorsiflexor muscles when the foot was restrained to a force transducer (force-control task) compared with supporting an equivalent inertial load unrestrained in the sagittal plane (position-control task). Seventeen young (23.6 ± 6.5 yr) and 12 old (70.0 ± 5.0 yr) adults performed the force-control and position-control tasks at 30% maximal voluntary contraction (MVC) until task failure on separate days. Despite the similar load torque for each task, time to failure was longer …
Reliability Of Surface Electromyography During Maximal Voluntary Isometric Contractions, Jump Landings, And Cutting, Mckenzie Fauth, Erich Petushek, Christina Feldmann, Brittni Hsu, Luke Garceau, Brittney Lutsch, William Ebben
Reliability Of Surface Electromyography During Maximal Voluntary Isometric Contractions, Jump Landings, And Cutting, Mckenzie Fauth, Erich Petushek, Christina Feldmann, Brittni Hsu, Luke Garceau, Brittney Lutsch, William Ebben
Exercise Science Faculty Research and Publications
The reliability of electromyographic (EMG) data has been examined for isometric and slow dynamic tasks, but little is known about the repeatability of this data for ballistic movements. The purpose of this study was to examine the within-session, trial-to-trial reliability of a variety of quadriceps and hamstrings muscles during isometric and ballistic activities. Data were analyzed by way of intraclass correlation coefficients (ICC), intersubject coefficients of variation (CVinter), and intrasubject coefficients of variation (CVintra). Twenty-four subjects performed 3 repetitions each of 2 randomly ordered test exercises, including landing from a depth jump (J) and cutting after …
Gender-Based Analysis Of Hamstring And Quadriceps Muscle Activation During Jump Landings And Cutting, William Ebben, Mckenzie Fauth, Erich Petushek, Luke Garceau, Brittni Hsu, Brittney Lutsch, Christina Feldmann
Gender-Based Analysis Of Hamstring And Quadriceps Muscle Activation During Jump Landings And Cutting, William Ebben, Mckenzie Fauth, Erich Petushek, Luke Garceau, Brittni Hsu, Brittney Lutsch, Christina Feldmann
Exercise Science Faculty Research and Publications
This study evaluated gender differences in the magnitude and timing of hamstring and quadriceps activation during activities that are believed to cause anterior cruciate ligament (ACL) injuries. Twelve men (age = 21.0 ± 1.2 years; body mass = 81.61 ± 13.3 kg; and jump height = 57.61 ± 10.15 cm) and 12 women (age = 19.91 ± 0.9 years; body mass = 64.36 ± 6.14 kg; and jump height = 43.28 ± 7.5) performed 3 repetitions each of the drop jump (jump) normalized to the subject's vertical jump height, and a sprint and cut at a 45-degree angle (cut). Electromyography …
Sex Differences In Response To Cognitive Stress During A Fatiguing Contraction, Tejin Yoon, Manda Linea Keller, Bonnie Schlinder-Delap, April L. Harkins, Romuald Lepers, Sandra K. Hunter
Sex Differences In Response To Cognitive Stress During A Fatiguing Contraction, Tejin Yoon, Manda Linea Keller, Bonnie Schlinder-Delap, April L. Harkins, Romuald Lepers, Sandra K. Hunter
Exercise Science Faculty Research and Publications
This study compared the time to task failure for a submaximal fatiguing contraction in the presence and absence of a cognitive stressor in men and women. In study 1, 10 men and 10 women (22 ± 3 yr of age) performed an isometric fatiguing contraction at 20% maximal voluntary contraction force until task failure with the elbow flexor muscles during two separate sessions. Subjects performed a mental-math task during one of the fatiguing contractions that aimed to increase anxiety and stress (stressor session). Salivary cortisol and reported levels of arousal (visual analog scale for anxiety, and State-Trait Anxiety Inventory …
Sex Differences And Mechanisms Of Task-Specific Muscle Fatigue, Sandra K. Hunter
Sex Differences And Mechanisms Of Task-Specific Muscle Fatigue, Sandra K. Hunter
Exercise Science Faculty Research and Publications
Women can be less fatigable than men due to sex-related differences within the neuromuscular system that impact physiological adjustments during a fatiguing task. The involved mechanism(s) for the sex difference, however, is task specific. This review explores the novel hypothesis that variation of the task will alter the magnitude of the sex-difference in muscle fatigue and the contribution of involved mechanisms.
Does Plasma Ss-Endorphin Influence Exercise-Induced Hypoalgesia In Healthy Adults?, Kathy Lemley
Does Plasma Ss-Endorphin Influence Exercise-Induced Hypoalgesia In Healthy Adults?, Kathy Lemley
Maria Dittman Library Research Competition: Student Award Winners
Anecdotal reports can be found in the literature of athletes who suffer from an injury, yet continue to participate in their sport with little or no pain. These reports have resulted in an interest in the possible role of stress, including exercise, in analgesia. Exercise-induced hypoalgesia (EIH), a decrease in pain perception following exercise, has been found to occur in healthy adults. In the 1970’s opioid peptides with analgesic properties were discovered (Dalayeun, Nores & Bergal, 1993). One of these peptides, β-endorphin, is believed to be released from the anterior pituitary into the circulation under a variety of stressors, including …
Sex Differences In Time To Task Failure And Blood Flow For An Intermittent Isometric Fatiguing Contraction, Sandra K. Hunter, Erin E. Griffith, Kristine M. Schlachter, Tim D. Kufahl
Sex Differences In Time To Task Failure And Blood Flow For An Intermittent Isometric Fatiguing Contraction, Sandra K. Hunter, Erin E. Griffith, Kristine M. Schlachter, Tim D. Kufahl
Exercise Science Faculty Research and Publications
The purpose of this study was to compare the time to task failure, postcontraction hyperemia, and vascular conductance of young men and women for a submaximal intermittent fatiguing contraction performed with the handgrip muscles. Twenty men and 20 women (mean SD: 22 4 years) performed an isometric contraction at 50% of maximal voluntary contraction (MVC) (6-s contraction, 4-s rest) until task failure. Forearm venous occlusion plethysmography was used to estimate the peak blood flow (after 10-min occlusion) and blood flow at rest after 6-s submaximal contractions of varying intensities, and during an intermittent fatiguing contraction at 1-min intervals and task …
Recovery From Supraspinal Fatigue Is Slowed In Old Adults After Fatiguing Maximal Isometric Contractions, Sandra K. Hunter, Gabrielle Todd, Jane E. Butler, Simon C. Gandevia, Janet L. Taylor
Recovery From Supraspinal Fatigue Is Slowed In Old Adults After Fatiguing Maximal Isometric Contractions, Sandra K. Hunter, Gabrielle Todd, Jane E. Butler, Simon C. Gandevia, Janet L. Taylor
Exercise Science Faculty Research and Publications
This study compared the contribution of supraspinal fatigue to muscle fatigue in old and young adults. Transcranial magnetic stimulation (TMS) of motor cortex was used to assess voluntary activation during maximal voluntary contractions (MVCs) of elbow flexor muscles in 17 young adults (25.5 ± 3.6 yr; mean ± SD) and 7 old adults (73.0 ± 3.3 yr). Subjects performed a fatigue task involving six sustained MVCs (22-s duration, separated by 10 s). Young adults exhibited greater reductions in maximal voluntary torque (67 ± 15% of baseline) than the old (37 ± 6%; P < 0.001). Increments in torque (superimposed twitch) generated by TMS during sustained MVCs increased for the young and old(P < 0.001) but were larger for the old adults at the start of the sustained contractions and during recovery (P < 0.05). Voluntary activation was less for the old adults at the start of some sustained contractions and during recovery(P = 0.02). Motor-evoked potential …
Time To Task Failure And Muscle Activation Vary With Load Type For A Submaximal Fatiguing Contraction With The Lower Leg, Sandra K. Hunter, Tejin Yoon, Joseph Farinella, Erin E. Griffith, Alexander V. Ng
Time To Task Failure And Muscle Activation Vary With Load Type For A Submaximal Fatiguing Contraction With The Lower Leg, Sandra K. Hunter, Tejin Yoon, Joseph Farinella, Erin E. Griffith, Alexander V. Ng
Exercise Science Faculty Research and Publications
The purpose was to compare the time to failure and muscle activation patterns for a sustained isometric submaximal contraction with the dorsiflexor muscles when the foot was restrained to a force transducer (force task) compared with supporting an equivalent inertial load and unrestrained (position task). Fifteen men and women (mean ± SD; 21.1 ± 1.4 yr) performed the force and position tasks at 20% maximal voluntary contraction force until task failure. Maximal voluntary contraction force performed before the force and position tasks was similar (333 ± 71 vs. 334 ± 65 N), but the time to task failure was briefer …
Supraspinal Fatigue Does Not Explain The Sex Difference In Muscle Fatigue Of Maximal Contractions, Sandra K. Hunter, Jane E. Butler, Gabrielle Todd, Simon C. Gandevia, Janet L. Taylor
Supraspinal Fatigue Does Not Explain The Sex Difference In Muscle Fatigue Of Maximal Contractions, Sandra K. Hunter, Jane E. Butler, Gabrielle Todd, Simon C. Gandevia, Janet L. Taylor
Exercise Science Faculty Research and Publications
Young women are less fatigable than young men for maximal and submaximal contractions, but the contribution of supraspinal fatigue to the sex difference is not known. This study used cortical stimulation to compare the magnitude of supraspinal fatigue during sustained isometric maximal voluntary contractions (MVCs) performed with the elbow flexor muscles of young men and women. Eight women (25.6 ± 3.6 yr, mean ± SD) and 9 men (25.4 ± 3.8 yr) performed six sustained MVCs (22-s duration each, separated by 10 s). Before the fatiguing contractions, the men were stronger than the women (75.9 ± 9.2 vs. 42.7 ± …
Active Hyperemia And Vascular Conductance Differ Between Men And Women For An Isometric Fatiguing Contraction, Sandra K. Hunter, Jennie M. Schletty, Kristine M. Schlachter, Erin E. Griffith, Aaron J. Polichnowski, Alexander V. Ng
Active Hyperemia And Vascular Conductance Differ Between Men And Women For An Isometric Fatiguing Contraction, Sandra K. Hunter, Jennie M. Schletty, Kristine M. Schlachter, Erin E. Griffith, Aaron J. Polichnowski, Alexander V. Ng
Exercise Science Faculty Research and Publications
To understand the role of muscle perfusion in the sex differences of muscle fatigue, we compared the time to task failure, postcontraction (active) hyperemia, and vascular conductance for an isometric fatiguing contraction performed by young men and women with the handgrip muscles at 20% of maximal voluntary contraction (MVC) force. In study 1, the men (n = 16) were stronger than the women (n = 18), and study 2, the men (n = 7) and women (n = 7) were matched for strength. Isometric contractions were sustained during two sessions: 1) until the target …
Effects Of Sprint Training On Extrarenal Potassium Regulation With Intense Exercise In Type 1 Diabetes, Alison R. Harmer, Patricia A. Ruell, Michael J. Mckenna, Donald J. Chisholm, Sandra K. Hunter, Jeanette M. Thom, Norman R. Morris, Jeff R. Flack
Effects Of Sprint Training On Extrarenal Potassium Regulation With Intense Exercise In Type 1 Diabetes, Alison R. Harmer, Patricia A. Ruell, Michael J. Mckenna, Donald J. Chisholm, Sandra K. Hunter, Jeanette M. Thom, Norman R. Morris, Jeff R. Flack
Exercise Science Faculty Research and Publications
Effects of sprint training on plasma K+ concentration ([K+]) regulation during intense exercise and on muscle Na+-K+-ATPase were investigated in subjects with Type 1 diabetes mellitus (T1D) under real-life conditions and in nondiabetic subjects(CON). Eight subjects with T1D and seven CON undertook 7 wk of sprint cycling training. Before training, subjects cycled to exhaustion at 130% peak O2 uptake. After training, identical work was performed. Arterialized venous blood was drawn at rest, during exercise, and at recovery and analyzed for plasma glucose, [K+], Na+ concentration ([Na+]), catecholamines, …
Variability Of Motor Unit Discharge And Force Fluctuations Across A Range Of Muscle Forces In Older Adults, Brian L. Tracy, Katrina S. Maluf, Jennifer L. Stephenson, Sandra K. Hunter
Variability Of Motor Unit Discharge And Force Fluctuations Across A Range Of Muscle Forces In Older Adults, Brian L. Tracy, Katrina S. Maluf, Jennifer L. Stephenson, Sandra K. Hunter
Exercise Science Faculty Research and Publications
Variability of motor unit discharge is a likely contributor to the greater force fluctuations observed in old adults at low muscle forces. We sought to determine whether the variability of motor unit discharge rate underlies the fluctuations in force during steady contractions across a range of forces in young (n = 11) and old (n = 14) adults. The coefficient of variation (CV) for discharge rate and force were measured during a force-matching task as the first dorsal interosseous muscle performed isometric contractions. The recruitment thresholds of the 78 motor units ranged from 0.04% to 34% of maximal …
Muscle Endurance Is Greater For Old Men Compared With Strength-Matched Young Men, Sandra K. Hunter, Ashley Critchlow, Roger M. Enoka
Muscle Endurance Is Greater For Old Men Compared With Strength-Matched Young Men, Sandra K. Hunter, Ashley Critchlow, Roger M. Enoka
Exercise Science Faculty Research and Publications
The purpose was to compare the time to task failure for a sustained isometric contraction performed at a submaximal intensity with the elbow flexor muscles by young and old men who were matched for strength. Eight young men (18–31 yr) and eight old men (67–76 yr) sustained an isometric contraction at 20% of maximal voluntary contraction (MVC) torque until the target torque could no longer be achieved for at least 5 s. The maximal torque exerted at the wrist was similar for the young and old men before the fatiguing task (65.9 ± 8.0 vs. 65.4 ± 8.7 N·m; P …
Influence Of Aging On Sex Differences In Muscle Fatigability, Sandra K. Hunter, Ashley Critchlow, Roger M. Enoka
Influence Of Aging On Sex Differences In Muscle Fatigability, Sandra K. Hunter, Ashley Critchlow, Roger M. Enoka
Exercise Science Faculty Research and Publications
The purpose of this study was to compare time to task failure for a sustained isometric contraction performed at a submaximal intensity with elbow flexor muscles by young and old men and women. Twenty-seven young (14 men and 13 women, 18–35 yr) and 18 old (10 men and 8 women, 65–80 yr) adults sustained an isometric contraction at 20% of maximal voluntary contraction torque until target torque could no longer be achieved for ≥5 s. Young adults were stronger than old adults (66.8 ± 17.9 vs. 47.7 ± 18.1 N·m, P < 0.05), and men were stronger than women (69.8 ± 17.9 vs. 47.1 ± 15.3 N·m, P < 0.05), with no interaction between age and sex (P > 0.05). Time to task failure was longer …
Men Are More Fatigable Than Strength-Matched Women When Performing Intermittent Submaximal Contractions, Sandra K. Hunter, Ashley Critchlow, In-Sik Shin, Roger M. Enoka
Men Are More Fatigable Than Strength-Matched Women When Performing Intermittent Submaximal Contractions, Sandra K. Hunter, Ashley Critchlow, In-Sik Shin, Roger M. Enoka
Exercise Science Faculty Research and Publications
The purpose of this study was to compare the time to task failure for a series of intermittent submaximal contractions performed with the elbow flexor muscles by men and women who were matched for strength (n = 20, 18–34 yr). The fatigue task comprised isometric contractions at 50% of maximal voluntary contraction (MVC) torque (6-s contraction, 4-s rest). The MVC torque was similar for the men and women [64.8 ± 9.2 (SD) vs. 62.2 ± 7.9 N·m; P > 0.05]. However, the time to task failure was longer for the women (1,408 ± 1,133 vs. 513 ± 194 s; P …
Fatigability Of The Elbow Flexor Muscles For A Sustained Submaximal Contraction Is Similar In Men And Women Matched For Strength, Sandra K. Hunter, Ashley Critchlow, In-Sik Shin, Roger M. Enoka
Fatigability Of The Elbow Flexor Muscles For A Sustained Submaximal Contraction Is Similar In Men And Women Matched For Strength, Sandra K. Hunter, Ashley Critchlow, In-Sik Shin, Roger M. Enoka
Exercise Science Faculty Research and Publications
The purpose of this study was to compare the time to task failure for a submaximal fatiguing contraction sustained with the elbow flexor muscles by men and women who were matched for strength (n = 20, 18-35 yr). The maximal torque exerted at the wrist was similar for the men and women [64.5 ± 8.7 (SD) vs. 64.5 ± 8.3 N·m; P > 0.05], which meant that the average torque exerted during the fatiguing contraction [20% of maximum voluntary contraction (MVC)] was similar for the two sexes. The time to task failure was similar for these strength-matched men and women …
Ventilatory Phenotypes Among Four Strains Of Adult Rats., Matthew Hodges, Hubert Forster, Paula E. Papanek, Melinda R. Dwinell, Genevieve E. Hogan
Ventilatory Phenotypes Among Four Strains Of Adult Rats., Matthew Hodges, Hubert Forster, Paula E. Papanek, Melinda R. Dwinell, Genevieve E. Hogan
Exercise Science Faculty Research and Publications
Our purpose in this study was to identify different ventilatory phenotypes among four different strains of rats. We examined 114 rats from three in-house, inbred strains and one outbred strain: Brown Norway (BN;n = 26), Dahl salt-sensitive (n = 24), Fawn-hooded Hypertensive (FHH: n = 27), and outbred Sprague-Dawley rats (SD; n = 37). We measured eupneic (room air) breathing and the ventilatory responses to hypoxia (12% O2-88% N2), hypercapnia (7% CO2), and two levels of submaximal exercise. Primary strain differences were between BN and the other strains. BN rats had a …
Angiotensin Ii And Vegf Are Involved In Angiogenesis Induced By Short-Term Exercise Training, Sandra L. Amaral, Paula E. Papanek, Andrew S. Greene
Angiotensin Ii And Vegf Are Involved In Angiogenesis Induced By Short-Term Exercise Training, Sandra L. Amaral, Paula E. Papanek, Andrew S. Greene
Exercise Science Faculty Research and Publications
Results from our laboratory have suggested a pathway involving angiotensin II type 1 (AT1) receptors and vascular endothelial growth factor (VEGF) in angiogenesis induced by electrical stimulation. The present study investigated if similar mechanisms underlie the angiogenesis induced by short-term exercise training. Seven days before training and throughout the training period, male Sprague-Dawley rats received either captopril or losartan in their drinking water. Rats underwent a 3-day treadmill training protocol. The tibialis anterior and gastrocnemius muscles were harvested under anesthesia and lightly fixed in formalin (vessel density) or frozen in liquid nitrogen (VEGF expression). In controls, treadmill training …
Distance Running, Orville O'Neil
Distance Running, Orville O'Neil
Bachelors’ Theses
This is a brief account or the history and development of long distance running in the United States and foreign ·countries.