Original articles   

The Journal of Sports Medicine and Physical Fitness 2000 June;40(2):110-7

Copyright © 2002 EDIZIONI MINERVA MEDICA

lingua: Inglese

Cross transfer effects of muscular endurance during training and detraining

Yuza N., Ishida K., Miyamura M.

From the Laboratory of Exercise Physiology Junior College Division of Chukyo Women’s University, Obu, Aichi, Japan * Research Center of Health Physical Fitness and Sports Nagoya University, Nagoya, Aichi, Japan

Background. To clar­i­fy 1) how the ­cross-trans­fer ­effect, ­obtained in a con­tra­lat­er­al ­untrained fore­arm ­through a 4-week ipsi­lat­er­al endu­rance train­ing reg­i­men, is ­changed dur­ing detrain­ing; and 2) how ­blood ­flow to the ­untrained ­limb is relat­ed to the trans­fer ­effect of mus­cu­lar endu­rance dur­ing train­ing and detrain­ing peri­ods.
Methods. Training reg­i­men: hand-­grip train­ing by ­means of a ­hand-ergom­e­ter ­with a ­work-­load of 1/3 of the max­i­mum ­hand-­grip ­strength 5 ­times a ­week for 4 ­weeks. Blood ­flow: a mer­cu­ry-in-rub­ber ­strain-­gauge for ­venous occlu­sion ple­thys­mog­ra­phy.
Measures: 1) maximal num­ber of con­trac­tions to deter­mine the mus­cu­lar endu­rance; 2) reac­tive hyper­aem­ic ­blood ­flow ­response (­RHBF3) to deter­mine wheth­er max­i­mal vas­o­dil­a­to­ry capac­ity ­would be ­changed in ­both the fore­arms ­post-train­ing and detrain­ing; and 3) max­i­mal ­work-relat­ed ­blood ­flow.
Results. We ­found sig­nif­i­cant incre­ments ­both in the mus­cle endu­rance and the max­i­mal ­work-relat­ed ­blood ­flow not ­only in the ­trained (+125%, +30%) but ­also in the ­untrained (+40%, +19%) fore­arms. During detrain­ing, we ­found decreas­es ­both in the mus­cle endu­rance and the max­i­mal ­work-relat­ed ­blood ­flow (-22%, p<0.01; -16%, p=0.053) of the ­trained fore­arm. However, in the ­untrained arm (-3%, NS) the ­cross-trans­fer ­effect of mus­cu­lar endu­rance ­remained ­unchanged ­despite a ­drop in the max­i­mal ­work-relat­ed ­blood ­flow (-17%, p<0.05). The ­RHBF3 did not ­change in ­either of the fore­arms dur­ing the ­whole peri­ods.
Conclusions. These find­ings sug­gest ­that the main­te­nance of the ­cross trans­fer ­effect of mus­cle endu­rance dur­ing detrain­ing can­not be ­explained on the ­basis of chang­es in fore­arm ­blood ­flow.