Abstract: | Swallow, John G., Theodore Garland, Jr., Patrick A. Carter,Wen-Zhi Zhan, and Gary C. Sieck. Effects of voluntary activity andgenetic selection on aerobic capacity in house mice(Mus domesticus). J. Appl. Physiol. 84(1): 69-76, 1998. An animal model was developed to study effects on components ofexercise physiology of both "nature" (10 generations of geneticselection for high voluntary activity on running wheels) and"nurture" (7-8 wk of access or no access to running wheels,beginning at weaning). At the end of the experiment, mice from bothwheel-access groups were significantly lighter in body mass than micefrom sedentary groups. Within the wheel-access group, a statisticallysignificant, negative relationship existed between activity and finalbody mass. In measurements of maximum oxygen consumption during forcedtreadmill exercise ( O2 max), mice withwheel access were significantly more cooperative than sedentary mice;however, trial quality was not a significant predictor of individualvariation in O2 max.Nested two-way analysis of covariance demonstrated that both geneticselection history and access to wheels had significant positive effects on O2 max.A 12% difference in O2 max existedbetween wheel-access selected mice, which had the highestmass-corrected O2 max, andsedentary control mice, which had the lowest. The respiratory exchangeratio at O2 max wasalso significantly lower in the wheel-access group. Our results suggestthe existence of a possible genetic correlation between voluntaryactivity levels (behavior) and aerobic capacity (physiology). |