I was able to use a regular backpack (swissgear laptop bag) if I needed to, but generally rode with my Shoei backpack instead. It did have marginally longer straps and had both a chest and waist strap.
In hindsight, I wish I had got something more like this:
Cortech by Tour Master Super 2.0 Backpack :: MotorcycleGear.com
My Shoei bag was great at holding a helmet, but the large single opening meant everything I put in there got mixed up by the time I arrived.