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Full-Text Articles in Medicine and Health Sciences

Sex Differences In Response To Cognitive Stress During A Fatiguing Contraction, Tejin Yoon, Manda Keller, Bonnie Schlinder-Delap, April Harkins, Romuald Lepers, Sandra Hunter Mar 2015

Sex Differences In Response To Cognitive Stress During A Fatiguing Contraction, Tejin Yoon, Manda Keller, Bonnie Schlinder-Delap, April Harkins, Romuald Lepers, Sandra Hunter

Bonnie A Schlinder-Delap Mrs.

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 scores) …


Suprasinal Fatigue Impedes Recovery From A Low-Intensity Sustained Contraction In Old Adults, Tejin Yoon, Bonnie Schlinder-Delap, Manda Keller, Sandra Hunter Mar 2015

Suprasinal Fatigue Impedes Recovery From A Low-Intensity Sustained Contraction In Old Adults, Tejin Yoon, Bonnie Schlinder-Delap, Manda Keller, Sandra Hunter

Bonnie A Schlinder-Delap Mrs.

This study determined the contribution of supraspinal fatigue and contractile properties to the age difference in neuromuscular fatigue during and recovery from a low-intensity sustained contraction. Cortical stimulation was used to evoke measures of voluntary activation and muscle relaxation during and after a contraction sustained at 20% of maximal voluntary contraction (MVC) until task failure with elbow flexor muscles in 14 young adults (20.9 ± 3.6 years, 7 men) and 14 old adults (71.6 ± 5.4 years, 7 men). Old adults exhibited a longer time to task failure than the young adults (23.8 ± 9.0 min vs. 11.5 ± 3.9 …


Fatigability And Recovery Of Arm Muscles With Advanced Age For Dynamic And Isometric Contractions, Tejin Yoon, Bonnie Schlinder-Delap, Sandra K. Hunter Mar 2015

Fatigability And Recovery Of Arm Muscles With Advanced Age For Dynamic And Isometric Contractions, Tejin Yoon, Bonnie Schlinder-Delap, Sandra K. Hunter

Bonnie A Schlinder-Delap Mrs.

This study determined whether age-related mechanisms can increase fatigue of arm muscles during maximal velocity dynamic contractions, as it occurs in the lower limb. We compared elbow flexor fatigue of young (n = 10, 20.8 ± 2.7 years) and old men (n = 16, 73.8 ± 6.1 years) during and in recovery from a dynamic and an isometric postural fatiguing task. Each task was maintained until failure while supporting a load equivalent to 20% of maximal voluntary isometric contraction (MVIC) torque. Transcranial magnetic stimulation (TMS) was used to assess supraspinal fatigue (superimposed twitch, SIT) and muscle relaxation. Time to failure …


Supraspinal Fatigue Impedes Recovery From A Low-Intensity Sustained Contraction In Old Adults, Tejin Yoon, Bonnie Schlinder-Delap, Manda Keller, Sandra Hunter Mar 2015

Supraspinal Fatigue Impedes Recovery From A Low-Intensity Sustained Contraction In Old Adults, Tejin Yoon, Bonnie Schlinder-Delap, Manda Keller, Sandra Hunter

Bonnie A Schlinder-Delap Mrs.

This study determined the contribution of supraspinal fatigue and contractile properties to the age difference in neuromuscular fatigue during and recovery from a low-intensity sustained contraction. Cortical stimulation was used to evoke measures of voluntary activation and muscle relaxation during and after a contraction sustained at 20% of maximal voluntary contraction (MVC) until task failure with elbow flexor muscles in 14 young adults (20.9 ± 3.6 yr, 7 men) and 14 old adults (71.6 ± 5.4 yr, 7 men). Old adults exhibited a longer time to task failure than the young adults (23.8 ± 9.0 vs. 11.5 ± 3.9 min, …