Too Hard, Too Often
The training intensity distribution of the typical age-group runner is very different from that of the average professional. This was demonstrated a number of years ago when researchers at Arizona State University asked a group of 30 female runners to describe their training. According to these self-reports, the women did three easy runs, one moderate-intensity run, and 1.5 high-intensity runs per week. But data collected from heart-rate monitors that the researchers gave to the women to wear through one full week of training told a different story. In reality the women did less than half of their training in the low-intensity range, almost half in the moderate-intensity range, and less than 9 percent in the high-intensity range.
Why do age-group runners do so much less easy running than elite runners? I think it’s mainly because age-groupers run a lot less, so they naturally push the pace a bit in most of their runs to make them “count” more. The problem with this approach is that running at a moderately high intensity (near the lactate threshold) is exponentially more taxing on the sympathetic nervous system than running slower. Therefore runners who run at this intensity day after day develop a burden of fatigue that they carry throughout the training process and that prevents them from getting as much out of their running as they would if they ran the same amount but slowed down most of the time.
One study involving Spanish runners found that those who did 80 percent of their training below the lactate threshold, 10 percent at LT, and 10 percent above LT improved their race times significantly more in five months than runners who did the same amount of running but performed only 70 percent of it below LT, 20 percent at LT, and 10 percent above LT.
The training intensity distribution of the more successful runners in this study—80 percent low, 10 percent moderate, and 10 percent high—is believed to be optimal for most runners. Call it the 80/10/10 rule, and compare it to the 45/45/10 training intensity distribution of the women in the ASU study, which represents the norm for age-group runners. Correcting this imbalance is one of the simplest and most effective ways that the typical age-group runner can improve his or her running. So how is it done?