TY - JOUR
T1 - Intensity-dependent effect of ageing on fatigue during intermittent contractions of the human calf muscle in males and females
AU - Reilly, Heather
AU - Egana, Mikel
AU - Green, Simon
PY - 2015
Y1 - 2015
N2 - Ageing reduces fatigue during submaximal intermittent contractions, but the influence of intensity on this ageing effect in males and females is not clear. Younger males (n = 8; 23 ± 2 years), younger females (n = 8; 22 ± 1 years), older males (n = 8; 67 ± 5 years) and older females (n = 10; 64 ± 7 years) completed intermittent calf contractions at four submaximal intensities (30–70 %MVC) for up to 20 min. MVC was assessed during exercise at 30–60 s intervals and its linear rate of decline represented fatigue. Individual relationships between intensity and fatigue (%MVC min−1) were fitted to a biphasic function consisting of a linear and nonlinear component. There was no age à sex à intensity interaction for fatigue (3-way ANOVA, P = 0.46). However, there were significant interactive effects of age and sex on endurance at 70 %MVC, fatigue at 70 %MVC and the linear component of the intensity–fatigue relationship. Endurance was lower and fatigue and its linear component were greater (P < 0.05) in younger males compared with other groups, but not different between younger and older females. This suggests that there is an intensity-dependent effect of human ageing on fatigue during submaximal exercise that is specific to males.
AB - Ageing reduces fatigue during submaximal intermittent contractions, but the influence of intensity on this ageing effect in males and females is not clear. Younger males (n = 8; 23 ± 2 years), younger females (n = 8; 22 ± 1 years), older males (n = 8; 67 ± 5 years) and older females (n = 10; 64 ± 7 years) completed intermittent calf contractions at four submaximal intensities (30–70 %MVC) for up to 20 min. MVC was assessed during exercise at 30–60 s intervals and its linear rate of decline represented fatigue. Individual relationships between intensity and fatigue (%MVC min−1) were fitted to a biphasic function consisting of a linear and nonlinear component. There was no age à sex à intensity interaction for fatigue (3-way ANOVA, P = 0.46). However, there were significant interactive effects of age and sex on endurance at 70 %MVC, fatigue at 70 %MVC and the linear component of the intensity–fatigue relationship. Endurance was lower and fatigue and its linear component were greater (P < 0.05) in younger males compared with other groups, but not different between younger and older females. This suggests that there is an intensity-dependent effect of human ageing on fatigue during submaximal exercise that is specific to males.
KW - aging
KW - exercise
KW - fatigue
KW - muscles
KW - sex
UR - http://handle.uws.edu.au:8081/1959.7/uws:31748
U2 - 10.1007/s00421-015-3178-9
DO - 10.1007/s00421-015-3178-9
M3 - Article
SN - 1439-6327
SN - 1439-6319
VL - 115
SP - 1927
EP - 1937
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
IS - 9
ER -