i agree with Prophetees3
the bible records that David danced before the lord with all HIS might, never said he was in the spirit to do such a thing
the bible said that the JOY of the lord is my strength
if that's the case we can say when one has joy they have strength and with strength comes the ability to win the battle
you dont have to be in the spirit to have joy, thus in my opinion you dont have to be in the spirit to express your happiness, joy, or gladness in the lord
as Prophetess3 said, shouting is a form of praise, something you express
as one song i listen to a lot says "he'll understand if your not perfect, or how it feels to know if you've been untrue, but the one whose never failed dont know like we know how good it feels to pray and have your faith renewed"
thus is the case point here, he dont know how it is to shout cause of where he hasnt had to experience the saving grace he provides, but we have and through our shouting it is a way of us expressing our love and appreciation towards him
IMO