I'm not running a race in July and August, so I'm doing something other than running to give my body and mind a break. Since the 25th of June I've started cycling and swimming once or twice a week. Of course I'm not training for triathlons. If these activities gave me a stronger aerobic engine my running would improve. I should usually see some gains.
I've read a debate focused on the relation between running and routine: the psychological effects of following the same routine can be just as limiting. After about only three or four weeks of the same low or high intensity training program, the benefit of running tend to decrease. Most experts say that "runners are creatures of habit, but this can be often lead to stagnating performance".