Tzitzit in the army

Q: Is it permissible not to wear Tzitzit during strenuous military exercises?
A: Only a four-cornered garment is obligated in Tzitzit. If you are not wearing a four-cornered garment, you are exempt from wearing Tzitzit. People do not usually wear four-cornered garments today, there thus seems to be no mitzvah of Tzitzit. But we should not avoid the mitzvah. The Shulchan Aruch (Orach Chaim 24:1) says that it is proper to deliberately wear a four-cornered garment in order to put on Tzitzit. And this is indeed our custom. The basic Halachah is that if a man does not want to wear Tzitzit under specific circumstances, such as army exercises, it is permissible. But it is better and more proper to always wear Tzitzit during military exercises and during war. During the time of Bar Cochba, they waged war wearing Tefillin (Gittin 57b-58a), we can therefore wage war wearing Tzitzit.