SOME PROPERTIES OF SINGLE MOTOR UNITS AT VOLUNTARY MUSCLE CONTRACTION AND RELAXATION
- VernacularTitle:筋収縮及び弛緩における運動単位のPhasic及びStaticな特性について
- Author:
SHIGERU MORIMOTO
;
HIDESHI HASEGAWA
- Publication Type:Journal Article
- From:Japanese Journal of Physical Fitness and Sports Medicine
1976;25(3):113-117
- CountryJapan
- Language:Japanese
-
Abstract:
It had been proposed by Kurata that the relative threshold value Fth of single motor units depends on gradient G (kg/sec) in the tension increase of muscle in such a manner as
Fth (=T1⋅G) =ρ⋅ Gλ
Here T1 is the time interval from the onset of E.M.G. to the moment of recruitment of a motor unit and ρ is the proportional constant. The motor unit with a positive/negative value of λ is characterized to be static/phasic.
In order to confirm the above relation and to see whether or not the relation is also valid in the relaxation period, single motor units of M. VAST US MEDIALIS were studied by the same method as that of Kurata.
The present findings are
1) At the contraction period the aove relation was confirmed.
2) At the relaxation period the above relation also holds, provided that Ftn and G are replaced by the tension at the moment of silence and the absolute value of G, respectively. The motor unit with a positive/negative value of λ is characterized to be phasic/static.
3) The value of Ftn and λ at the relaxation period are not the same as those at the contraction period.
