<human>:  What are some good physical activities for a person with a bad back?
<bot>: 
1. Swimming 
2. Pilates 
3. Yoga 
4. Walking 
5. Tai Chi 
6. Core Strengthening Exercises 
7. Low-Impact Aerobics 
8. Strength Training with Light Weights 
9. Elliptical Training 
10. Stretching Exercises