Exercise apparatus, comprises a first support means for the user's legs, a platform mounted on the support means to support a user's legs, there being a hinge connecting the platform to the support means and defining a generally horizontal hinge axis to allow pivoting of the user's trunk about a generally horizontal axis as the user relatively bends his body and his legs means, and extending in spaced, a second support means for the back of the user's body, and means for indexing said second support means at selected angularity relative to the hinge axis.