Hyperextensions (Back Extensions)
of a joint, "hyperextension" refers to bending it beyond its normal range of motion (usually this is bad). as an exercise, "hyperextensions" are performed using a roman chair which supports one's legs and hips in a horizontal, prone position. Either with or without a weight, one then bends at the hips, lowering one's head and shoulders until one's torso is close to vertical. Then, by contracting the glutes and spinal erectors , one raises one's torso back upwards to above the horizontal.