If you’re building mental stamina
A long run in the morning followed by an evening 15–20-minute recovery run is challenging but great for long-distance race simulation. “Since the athlete is already in a glycogen-depleted state, the run will require deeper glycogen utilization and additional mental and physical stamina to complete—skills that are particularly important in endurance racing,” Dollar says. He recommends that your secondary run be performed at an “embarrassingly slow pace” and be no longer than 20 minutes. Another option is to do your Saturday long ride followed by a transition run in the morning, then add in an evening 15-minute recovery run.