You sit next to the chair with your legs together and move up and down. If your legs are at a 90-degree angle, it will also exercise your abdomen.

Squat 30 times a day, and then massage properly. You'd better exercise your back T-leg. Not only lift your hips, but also make your legs PL! I will be useful! Climbing stairs is also very effective!

I think the most effective and simple thing is to squat for 30 degrees and climb the stairs. Others are too complicated to last long.