Iron-type golf club

A golf club head comprising a club head main body and a muscle back shell, wherein the club head main body comprises a first material and a partial sole, and the muscle back shell comprises a second material different from the first material, wherein the club head main body and the muscle back shell cooperate to improve the mass properties of the club head, wherein the club head main body comprises an elongate supporting member protruding rearward from a hitting face and across a portion of the hitting face in a generally heel to toe direction and supporting the hitting face to maintain the mechanical integrity of hitting face, wherein the supporting member protrudes rearward from the hitting face by a greater distance than the partial sole extends rearward from the hitting face, and wherein the muscle back shell, the hitting face and the supporting member define a hollow interior cavity in a muscle portion of the club head, the golf club head further comprising a third material having a lower density than the first material, wherein the third material is disposed between the muscle back shell and the main body.