Office workout exercises using chair is one of the easiest, which fits best for individuals who don’t have spare time to workout. The knee and leg strengthening, which is flex and extend practice, can be practised easily at home. In this unilateral exercise, you need to lift the leg, extend it firmly and follow it with a flex. Thereafter, place hands on the side handles of a chair while extending and bending. In a bilateral exercise, abs muscles are also worked. While practicing the exercise, you need to keep your back straight. The exercise is recommended for those affected by knee problems.