When working camps we would occasionally have very devout Mormons attend the 2 week intensive camp. If they asked they certainly got off on Sunday. And there was no morning session on Sunday so anyone who wanted to go to church could attend.
If the team is predominately muslim, this is probably the simplest way to do it. Really not a bad idea in general. Even with a “cold front” coming through now the heat index is still 89 here, and has been as high as 115 recently. You can’t drink enough to keep up with that while working out.
Heck, I would have loved to have late night practices when I ran cross country in high school. Summer practice started in mid-August (right around now), and the heat in upstate NY was sometimes pretty bad. Of course, there is the issue with lighting. It's easier to light a football field at night than a 5K running course that winds through the woods.