A trainer sees a client three days per week and works two muscle groups per...

A split-routine training system involves working different muscle groups on different days. The NASM CPT7 Study Guide describes this as an effective approach for clients training multiple times per week who want to increase training volume for specific muscle groups.

In the example, the trainer sees the client three days per week and trains two muscle groups per day—a textbook split routine (e.g., chest/triceps on day one, back/biceps on day two, legs/shoulders on day three).

By contrast:

Superset alternates two exercises with minimal rest.

Pyramid changes the weight and reps across sets.

Circuit training involves moving quickly between exercises targeting different muscle groups in sequence.

Therefore, the system described is split-routine.