A back brace including a back panel, opposed adjustable belt members for encircling a users abdomen, and at least one dynamic tension strap for applying an adjustable amount of compressive force. The back brace includes a pair of attachment flaps fixedly joined to opposite sides of the back panel. the attachment flaps and belt members have complementary fasteners for mating in a plurality of longitudinal positions to allow adjustment of the belts length for a broad range of abdomen sizes. The back panel may support a cinch point, and the dynamic tensioning system may include a strap looped through the cinch point and securable to a belt member to apply adjustably compressive force. The cinch points may be supported on straps adjustably fastenable to the back panel in a plurality of relative longitudinal positions to allow for adjustment of dynamic tensioning straps length for a broad range of abdomen sizes.