Abstract:
PURPOSE:The fluctuations in force during a steady contraction can be influenced by age, vision, and level of physiological arousal. The aim of this study was to determine the effects of a stressor on the force fluctuations and information transmission exhibited by young, middle-aged, and older adults when a pinch-grip task was performed with and without visual feedback. METHODS:Thirty-six men and women (19-86 yr) participated in a protocol that comprised anticipatory (30 min), stressor (15 min), and recovery periods (25 min). The stressor was a series of noxious electrical stimuli applied to the dorsal surface of the left hand. Subjects sustained a pinch-grip force with the right hand at 2% of the maximal voluntary contraction force. The normalized fluctuations in pinch-grip force (coefficient of variation), information transmission (log2 signal:noise), and the spectra for the force were quantified across the 70-min protocol. RESULTS:Removal of visual feedback exacerbated the force fluctuations (3.83+/- 3.15 vs 2.82+/- 1.64%) and reduced the information transmission (5.01+/- 0.86 vs 5.34+/- 0.71 bits) only during the stressor period. The effect was similar for all age groups. Older adults exhibited greater force fluctuations and lower information transmission compared with young and middle-aged adults, especially during the stressor period. The impairments in fine motor performance during the stressor were associated with an enhancement of the power at 1-2 Hz in the force spectrum (R=0.41-0.52). CONCLUSION:Removal of visual feedback increased the force fluctuations and decreased information transmission during a stressor period, which suggests that integration of visual feedback can attenuate the stressor-induced enhancement of synaptic input received by the motor neuron pool.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Christou EAdoi
10.1249/01.mss.0000178103.72988.cdsubject
Has Abstractpub_date
2005-12-01 00:00:00pages
2126-33issue
12eissn
0195-9131issn
1530-0315pii
00005768-200512000-00017journal_volume
37pub_type
杂志文章abstract::This randomized study compared the fibrinolytic circadian rhythm of healthy older men and older women (average age 66 +/- 5), before and after 6 months of endurance training versus stretching controls. Compared with men, women at baseline had similar rhythms for tissue plasminogen activator (t-PA) activity and plasmin...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1097/00005768-199606000-00001
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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doi:
更新日期:1992-09-01 00:00:00
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journal_title:Medicine and science in sports and exercise
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更新日期:2017-04-01 00:00:00
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章,随机对照试验
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更新日期:2003-04-01 00:00:00
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journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200106000-00024
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章,随机对照试验
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更新日期:1994-10-01 00:00:00
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journal_title:Medicine and science in sports and exercise
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journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,随机对照试验
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更新日期:2020-01-01 00:00:00
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journal_title:Medicine and science in sports and exercise
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