Neither women nor men showed changes in peak aerobic capacity after resistance training. Peak aerobic capacity was unaltered in both groups, regardless of sex. The primary outcome variable of interest was walking endurance time. Before the study intervention, none of the 24 participants completed the full 45-minute endurance protocol. Submaximal or peak exercise oxygen consumption did not change during the endurance testing.
Resistance training improves walking endurance in at least two ways.
Second, in view of the measured increase in leg strength, participants worked at lower percentages of their peak strength at a given workload, thereby using anaerobic mechanisms to a lesser degree. We did not monitor the physical activity of study participants at home, but it is unlikely that an increase in aerobic activity at home contributed to the increase in endurance capacity, because the aerobic capacity of the participants did not change. Sex differences were prominent both at baseline and in response to conditioning. At baseline, women had lower strength measures, lower fat-free mass, greater fat mass, and lower peak aerobic capacity. In response to resistance training, women had improvements in strength and fat-free mass of the leg that were somewhat greater than those of men, yet men increased their submaximal endurance to a greater degree.