21st Century Jews

When i was first given my teffilin the strap for the arm was cut a little too long, but whatever still fine. I am putting on teffillin for some time now and you know what happened? My left arm, the one I put my teffillin on, is now a little longer than my other one!

Of course, chassidic philosophy mentions how if the arm is stronger then the mitzvah of putting on teffilin becomes a stronger mitzvah in commensurate. So we heard of the arm affecting teffillin, but the teffillin affecting the arm? Well yes Jews used to wear teffillin in ancient battles, so perhaps it made them better fighters and back then fighting was quite physical, but who heard of teffillin making the arm fit it better?

Also, teh way the teffillin is wrapped around the forearm is very mystical but in the most general description we see for example, in a popular picture of the Rebbe wearing
teffilin, that more of the straps are wrapped closer together near the wrist.

When you use the arm the energy from the force goes through the wrist, and if you move teh arm in an unnecesary ways damage is done to the wrists. So the wrists are important. Is this the connection? To make the wrists stronger spirtually-physically by wrapping more straps of teffillin on them?