You're not cheating yourself if you ride a shorter distance than Group 1. If we all rode the same distance, Group 6 would end up training at the lowest relative intensity. For this ride, we're training by time, not distance.

The causes of muscular fatigue are not fully understood, but a major component is biochemical. One goal of training is to deplete biochemical substrates to stimulate adaptations that increase the size of stores and the recovery (replenishment) rate.

Route:

http://www.mapmyride.com/ride/united-states/ca/-los-altos/969125391661146998

L- Edith, L- Fremont, R- Robleda, R- Purissima, (Optional loop 1), L- Elena, R- Taaffe, R- Altamont, (Optional loop 2), turnaround at Altamont/Page Mill and begin rolling regroup, descend Altamont, straight to El Monte, R- Foothill and back.

Optional
Loop 1: (From Purissima)
R- Concepcion, R- Fremont, R- La Paloma, R- Purissima

Optional Loop 2: (From Altamont)