"Nós nunca costumamos nos exercitar."

Translation: We never used to exercise.

[microgriff]

is the nos really needed here ? just : nos nunca cosumamos exercitar ?

[Paulenrique]

yes. When someone exercises, he/she exercises on"him/herself" (hehe). So it's a reflexive verb (exercitar-se). Then, when you conjugate it, it becomes "nos exercitamos".