Multiple activities can have the same name if they are offered at multiple times or locations, since they can be distinguished by their activity numbers.
Name your activities so that when they are sorted alphabetically, similar activities are grouped together.
Your activity names do not need to include activity categories because categories are already separated in the database.
Within the Fitness activity category there may be a number of activities that you can group together by name:
Aerobics - Boxercise
Aerobics - Step
Dance - Ballet
Dance - Jazz
Dance - Tap
Strength - Circuit training
Strength - Free-weights
Yoga - Asthanga
Yoga - Hatha