9 Exercises You Can Do Without Getting Out of Your Chair

7. Bicycle

How to do it: 

• Sit high (chest flat and shoulders down) in the front half of a chair. 
• Grasp the sides slightly with your hands and lean back slightly, straining your abs, raise your right knee to chest height. 

• Lower it, then lift your left knee on the next rep. 
• Alternative. If you are good at it, try raising both knees at the same time.

Do up to 10 reps per leg.