Category Nuances for null:

• minor,
• familiar,
• healthy,
• compulsive,
• positive,
• routine,
• miscellaneous,
• physical,
• dynamic,
• common,
• individual,
• outdoor,
• complex,
• new,
• natural,
• everyday,
• efficient,
• important,
• animal,
• planned,
• preventative,
• strenuous,
• solitary,
• cardiovascular,
• enjoyable,
• heavy,
• innocuous,
• personal,
• appropriate,
• preventive,
• indoor,
• physiologic,
• recreational,
• joint,
• corporate,
• favorite,
• regular,
• rhythmic,
• crucial,
• beneficial,
• meaningful,
• increased,
• extreme,
• stimulating,
• external,
• local,
• extracurricular,
• usual,
• alternative,
• pleasurable,
• normal,
• incidental,
• actual,
• informal,
• basic,
• metabolic,

Simple Categories for null:

• training,
• activity,
• action,
• thing,
• behavior,
• task,
• exercise,
• preparation,
• event,
• project,
• exertion,
• recreation,
• practice,
• behaviour,
• effort,
• process,
• measure,
• work,
• care,
• outlet,