Which of the following is NOT one of the primary training categories?

The primary training categories in running typically include several key components such as threshold training, interval training, and active rest/recovery, each serving a distinct purpose in a runner's training program. Speed drills, while beneficial and commonly used, are generally considered a subset of speed work rather than a primary category on their own.

Active rest/recovery focuses on allowing the body time to repair and rejuvenate, which is essential for avoiding injury and improving overall performance. Threshold training is aimed at improving a runner's lactate threshold, which is crucial for sustained efforts. Interval training involves varied pacing and intensities, contributing significantly to building speed and endurance.

Since speed drills are not recognized as a standalone primary training category but rather contribute to speed work within a broader framework, this makes them the correct answer to the question.