Dear Rabbi Simon,
Would taking off tsitsit to play football for one hour require a beracha when putting them back on?
I would not think so, however if you shower afterwards, then yes. Particularly if you have in mind that the berachah in the morning applies only until you take the ציצית off. Of course if it is after dark no berachah in any case. (BTW, there are those who do not even put their tzitzit back on if they are dressing after dark. My practice is to do so, however.)
rabbi rashi simon