Movements have attributes describing what one would usually log, e.g. a Back Squat has_reps: true and has_load: true.

These are merely hints to a front end client that if you’re building a workout with a Back Squat in it, showing both a Reps and Load field is a good starting point. A workout can still choose to specify whatever fields it wants for any movement, regardless of what the movement’s default attributes are.

When creating a movement, specify what is usually logged, and if you ever have a niche use case later on, you can customize a workout as you see fit.