Regional changes in muscle mass and strength following 20 days of bed rest, and the effects on orthostatic tolerance capacity in young subjects
Suzuki, Y.; Murakami, T.; Kawakubo, K.; Haruna, Y.; Takenaka, K.; Goto, S.; Makita, Y.; Ikawa, S.; Gunji, A.
Journal of Gravitational Physiology a Journal of the International Society for Gravitational Physiology 1(1): P57-P58
1994
ISSN/ISBN: 1077-9248 PMID: 11538763 Document Number: 426154
To this day, many studies have suggested that prolonged bed rest (BR) affects on muscle mass and strength not only in gravity muscles but also in ungravity muscles. However, it is still unclear whether the decrease in regional muscle strength after BR is due to the alterations in the corresponding muscle mass, or not. On the other hand, if BR decreases the mass of antigravity muscles (UGM) as well as muscle strength and then increases tissue compliance of the antigravity muscles, orthostatic tolerance capacity will be decreased by the reduction in cardiac output (CO) in spite of the increase in myocardial contractility because the more decrease in venous return due to the more increase in blood pooling within the compliant tissues of the lower body. However, this is also unclear. To make these questions clear, the present study investigated the regional muscle mass and strength and orthostatic tolerance capacity before and after 20 days of bed rest in young subjects.