Abstract: A backpack has a pocket and at least one shoulder strap for supporting the backpack on a shoulder of a user. A generally rigid plate and a flexible inflatable bladder are in the pocket with a load bearing bag connected to the pocket for holding a load. A tubular extension extends from the bladder and into the shoulder strap for inflating and deflating the bladder and a mouth-inflatable check valve is connected to the tubular extension at a location spaced from the bladder and positioned so as to be accessible to the user for inflating the bladder by blowing into the check valve. A curved semirigid liner inside the material of the shoulder strap near the bladder forms a semirigid channel for receiving the tubular extension.

Abstract: A backpack has a pocket and at least one shoulder strap for supporting the backpack on a shoulder of a user. A generally rigid plate and a flexible inflatable bladder are in the pocket with a load bearing bag connected to the pocket for holding a load. A tubular extension extends from the bladder and into the shoulder strap for inflating and deflating the bladder and a mouth-inflatable check valve is connected to the tubular extension at a location spaced from the bladder and positioned so as to be accessible to the user for inflating the bladder by blowing into the check valve. A curved semirigid liner inside the material of the shoulder strap near the bladder forms a semirigid channel for receiving the tubular extension.

Abstract: A backpack has a generally rigid support having a front face and a back face, shoulder straps attached to the support for holding same against a back of a user, and structure on the back face for holding an object. A pressurizable and flexible bladder covers generally all of the front face of the support and has a closable fill opening. This bladder is secured to the front face of the support with the fill opening accessible.