Training-related changes in the R-R interval at the onset of passive movements in humans
Braz. j. med. biol. res
;
41(9): 825-832, Sept. 2008. graf, tab
Article
in English
| LILACS
| ID: lil-492880
ABSTRACT
The aim of the present study was to determine whether training-related alterations in muscle mechanoreflex activation affect cardiac vagal withdrawal at the onset of exercise. Eighteen male volunteers divided into 9 controls (26 ± 1.9 years) and 9 racket players (25 ± 1.9 years) performed 10 s of voluntary and passive movement characterized by the wrist flexion of their dominant and non-dominant limbs. The respiratory cycle was divided into four phases and the phase 4 R-R interval was measured before and immediately following the initiation of either voluntary or passive movement. At the onset of voluntary exercise, the decrease in R-R interval was similar between dominant and non-dominant forearms in both controls (166 ± 20 vs 180 ± 34 ms, respectively; P > 0.05) and racket players (202 ± 29 vs 201 ± 31 ms, respectively; P > 0.05). Following passive movement, the non-dominant forearm of racket players elicited greater changes than the dominant forearm (129 ± 30 vs 77 ± 17 ms; P < 0.05), as well as both the dominant (54 ± 20 ms; P < 0.05) and non-dominant (59 ± 14 ms; P < 0.05) forearms of control subjects. In contrast, changes in R-R interval elicited by the racket players' dominant forearm were similar to that observed in the control group, indicating that changes in R-R interval at the onset of passive exercise were not attenuated in the dominant forearm of racket players. In summary, cardiac vagal withdrawal induced by muscle mechanoreflex stimulation is well-maintained, despite long-term exposure to training.
Full text:
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Index:
LILACS (Americas)
Main subject:
Vagus Nerve
/
Racquet Sports
/
Baroreflex
/
Heart
/
Heart Rate
/
Mechanoreceptors
Type of study:
Observational study
Limits:
Adult
/
Humans
/
Male
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2008
Type:
Article
/
Project document
Affiliation country:
Brazil
Institution/Affiliation country:
SUPREMA/BR
/
Universidade Gama Filho/BR
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