An adjustable apparatus for exercising the neck including an assembly connected to an anchor by a tether that has an elastic portion. The assembly includes a cap, a harness to secure the cap on the head, and a saddle piece that extends across the back of the neck. The cap can be a helmet that forms a cam surface with a channel for slideably receiving the tether and a frontal extension forming a continuation of the cam surface. The tether is secured to the posterior of the helmet so as to extend over the cam surface to the anterior portion. The head assembly further includes a tether attachment adjustment mechanism, a harness adjusting ratchet, and a semi-rigid saddle to apply pressure to the neck of the person when the harness is tightened by the harness adjusting ratchet and when the head is tipped backwardly pulling on the tether.