Significance of transient decrease in sustained tension preceding rapid muscle contraction in man.
- VernacularTitle:動的筋収縮前の一過性の張力低下について
- Author:
KUNIATSU NAGAMI
- Publication Type:Journal Article
- Keywords:
Premotion silent period;
Transient tension decrease;
Muscle length;
Stretch reflex
- From:Japanese Journal of Physical Fitness and Sports Medicine
1987;36(3):116-127
- CountryJapan
- Language:Japanese
-
Abstract:
The purpose of this study is to investigate significance of transient decrease in sustained tension preceding rapid muscle contraction in elbow flexor muscles.
Before rapid voluntary contraction, steady forces below 20% of the maximum contraction were maintained, and each transient decreas was detected by using high sensitive strain gauge (FD pick-up) with EMG of brachial biceps and triceps muscles. And girth and length changes of the biceps brachii muscle with the tension decrease were detected by using rubber strain-gauge method and X-ray technique, respectively.
The following results were obtained
1) The transient decrease of steady forces were observed during the premotion silent period. Amount and duration of the transient tension decrease were below 20% of each steady force and 100 ms, respectively.
2) Amount of the transient tension decrease inversely correlated to time to half Pmax on the rapid tension development. (p<0.001)
3) Amount of the transient tension decrease was significantly coefficient with decrement of girth of upper arm. (p<0.001)
4) A distance between two Cu wire apexes inserted into biceps brachii muscle shortened with increment of muscle force.
These results suggest that before rapid muscle contraction stretch of biceps brachii muscle transiently occure, and that the stretch accelerate the following shortning velocity of the muscle via a stretch reflex.
