MTB clothing is all about comfort and durability. You need to be able to move around and take the twists and turns of the trail. So your MTB jersey should be light and roomy, without being so baggy that it gets in the way.
If you want to take this sport a little more seriously you should consider body armour. It will fit easily under or over your jersey and provide protection from heavy impacts. Our selection of Fox and Endura mountain bike clothing will have you ready to ride in all conditions.