The coach said that they _________ to the gym every day next week to get in shape for the tournament game.
- should go
- will go
- will be going
Any of the three options work. The sentence is reported speech. The reported speech includes the phrase "next week", which–when used properly–refers to a situation that has still not happened at the time of the reported speech. Since this is the case, the modal verb will is fine; it does not have to be backshifted in this case. Thus, both 2 and 3 are okay. 1 is also okay in this context.