In many Asian countries martial arts specialists use traditional ankle wraps and trousers that tighten at the ankles.Do you know why?They are used to compress the flow of blood to the person’s feet, by doing so they don’t swell up from being active all day. Another reason is , the wraps in ankles helps avoid sprain.Even to this day, monks in Shaolin use this.
I did a bit of research on this from a Chinese Kung Fu federation and this is what they told me.
There is an art to tying your leg wraps securely. They must be firm, yet not constrictive. As you move, the shape of your calf changes, so it you must follow the natural contours of your leg muscle as you make your ties. You may need readjusting over a long practice period., or after a particularly strenuous movement. Tying leg wraps can be time consuming, but it can also be a pre-practice meditation, a time to focus your energies on the task ahead. Learning to use these authentic leg wraps is an adjustment at first, but there is such great value in learning a traditional method, especially in Kung Fu. It gives you the direct experience and satisfaction of doing your own research, making discoveres, and honoring the ways of our martial ancestors.
What’s more? They were even used in World War II. British troops took the idea from Indian warriors and went on to call them as “puttee” which means band in Sanskrit.
Now coming back to the main question, most Japanese people grow up watching ninja shows and martial arts. Kishimoto probably wanted ninjas to be more realistic and hence added it.Not to forget, more than anything else it’s Cool!
This is my theory on this topic, if you would like to read more about it you can check out the official Shaolin site. Also, if you have your own theory, let me know about it via the comments section and let’s have a healthy discussion on the same.