It would mainly depend upon why they are super strong. If it's magic, then whatever. If they are mutants/next evolution then their weight should probably be roughly proportional to their size.
Super lean isn't a good thing because fat provides energy especially when healing wounds. As a surgeon, I often saw the lean people lose the most weight after a major procedure and trauma patients do better when they have at least a little fat.
Denser bones might be a realistic consideration because phosphorus is necessary for ATP (Adenosine Tri-Phosphate) which is used by all animal life in producing usable energy and the bones are the storehouse for phosphorus. However, bones that are too dense have too little space for marrow making the person anemic and therefore not strong. Five years ago I woke up one day with a broken back due to a metabolic kidney problem previously only recognized in renal transplant patients. A long story short; I had advanced osteoporosis. After years of what would be toxic doses of phosphorus for the average person my bones have gone from being rated as a 90 year old woman to a 50 year old man. My clothes sizes didn't change, yet I gained about 20 pounds. So, an extra 20 pounds or so to make bones denser than average would be reasonable, but probably not making them twice as heavy, unless they were twice as big. (Interesting sidenote about the phosphorus; I used to have intense cravings for things that most other people wouldn't eat, like bones. I'd gnaw the ends off of chicken bones and suck out the marrow until they were basically straws. Some people got weirded out by it and would ask, "Are you part dog?" I liked small fish like sardines and anchovies where you eat the bones. I found a more socially acceptable way to do it. Now I pressure cook the bones down into stock and can it for soup. The dogs don't bother with the bones after I've cooked out all the flavor and they are so brittle that they can be crushed by hand. My point is that unless they warriors are really big, I'd have them not be super dense, but just a little heavier than expected such that you'd need a scale to judge it, but mainly give them behavioral variances regarding their food cravings.)
Super-Bulky muscles are not usually a sign of the kind of strength that a warrior would need. It's usually a sign of anaerobic training so those people might be able to lift a giant weight once, but would likely keel over in exhaustion if forced to run half a mile. The other problem with bulky muscles is that their training is typically not across the full range of motion for a given muscle. Those muscles are much more likely to tear when called upon to do something other than the narrow range of training that produces that body shape.
Making them twice as heavy as they should look would also require a lot more energy to move that weight
