Some of my friends have hard bicep muscles (hard to the touch ... typically these guys like to go round pointing at their biceps saying "feel that ... see ... like a rock") and there are guys who can press their finger into their bicep because it is a lot softer. Yet, often there seems to be no strength difference between the two. Both can lift very similar weights in bicep curls etc ... and both seem to have very similar bodyfat levels.
Is it possible to build hard muscle ... or to harden existing muscle?
I don't think it has to do with removing fat as the muscle tissue itself is in question here, regardless of how much fat is surrounding it. For instance, I suspect sumo wrestlers have very hard and dense quads underneath all those layers of fatty tissue whereas many guys with low skin-fat have marshmallow where the muscle should be.
Thread: Hard Muscle v Soft Muscle