Hello!
This is not acceptable, on no level. I understand they might want to get a lead position within the school, however, if you have a routine workout schedule, it can be harmful to stop it and then get back into it. It can also cause your muscle to deteriorate quicker than someone who does not have a routine schedule. This can also cause emotional stress to the person because they are behind on schoolwork. Any position within a school is not as important as your physical shape and schoolwork. They should reach out to the person who is in charge of that lead position and inform them of the situation and if they don't understand then the position is not right for you anyways. Remember, and position can be replaced but your life and education can't.
I hope this helped!
I am, yours most sincerely,
SuperHelperThingy