Athletic crossword answers

 Across

4. Low impact

5. Shin splint

6. Fixed resistance

9. Endurance

11. Beta blockers

12. Static

13. Strength

14. Interval

16. Aerobic

17. Circuit training

18. Yoga

19. Body mass index

21. Lean mass

Down

1. Cool down

2. High impact

3. Repetition

6. Flexibility

7. Core

8. Pilates

9. Electrolytes

10. Plateau

15. Calisthenics

20. Warm up