“Junk miles” are submaximal rides or runs done just to meet weekly or monthly mileage targets, but not to achieve specific training gains.
Despite the name suggesting worthless volume, junk miles are usually active recovery, which helps to increase circulation and aerobic maintenance following intense workouts. Their utility is debated by training theories: some believe all miles accrue base endurance; others warn against too much low-level volume at the expense of quality workouts. Athletes will usually insert junk miles into workouts with quality workouts to gain top fitness and reduce fatigue.
