Question

Why do stretching exercises increase flexibility more than cardio exercises?

Answer 1

I don't think this is the right place to ask this question..... but...
Our human body, develops on usage, and deteriorates on use because of wear and tear.

So if you want to be flexible (say be able to touch your toes) you need to stretch the muscles around the hip, knee ,etc. That will loosen the muscles and give you flexibilty.

Comparatively, Cardio is the exercise of heart, stamina etc. This will help you in endurance but not so much in flexibility.