There are several factors to consider here.
What is covering the muscles? When you say he is like a rock, chances are his body fat and sub-q fat is much less than yours. This will give both the appearance and feel of the muscle being harder. Secondly, there are other factors (mechanical and neural) that regulate force production (strength) besides muscle size and even factors within the muscle that regulate force production.
Without a doubt, androgens will give muscles a much fuller and harder look, if they didn't, no one on this board would use them. I don't think any female on this board that has used AAS will disagree and this has to do with the amount of intramuscular glycogen, water and contractile proteins in a given space that can be affected by AAS. Anyone that is on a low carb diet knows that the muscles look soft and flat, but fill out (harden or become more dense looking) when carbs are increased as a function of increasing intramuscular water.
Muscle is composed of contractile (myosin, actin, etc.) and non-contractile proteins (connective tissue). Of course it is the contractile proteins that generate force. There is also interstitial space, or space within the muscle. A muscle with more interstitial space and/or less contractile protein will produce less force per cross-sectional area or unit of muscle and would be considered "less dense". There are also mechanical factors (bone attachments, angle of pull, etc.) that affect force production. Then there are neural factors, both at the muscle level and central (brain) that are influenced by androgens.
W6
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