I use my right hand for tasks that involve precise control such as writing. However, my left hand and foot are used for most sports, since they are more powerful and pretty coordinated as well. I have been putting Tefillin on my left arm. Am I acting correctly?
Thanks very much, I read your website regularly and have learned a lot.
It seems that you are doing correctly. There is controversy when someone writes with one hand but does all other actions with the other hand, however in your situation you write and do other acts that require fine coordination with your right hand, and not just writing. Therefore you can continue to put the tefillin on your left hand.
Shulchan Aruch and Rema 27-6, M:B ibid 26, Biur Halacha D:H V’hachi.