How to pack more quality into lower-mileage training plans

Examples of lower mileage training plans:

• Athletes can do two harder but longer-distance sessions per week, with a shorter recovery run the next day.
• Athletes can run four or five days per week with just one hard workout, such as 200-meter intervals. Long runs with varied intensity count as a quality session. 

Expert trainers advise you don't need to supplement your days off with another form of cardio to cross-train. Cross-training sessions depend on your schedule and motivations. Other experts believe it's better to let your body fully recover on days you're not running.