the claim is not that muscle sitting still burns more calories but that a very high weight exercise session burns more calories than a low weight exercise sessi

the claim is not that muscle sitting still burns more calories but that a very high weight exercise session burns more calories than a low weight exercise session. if you don't lift heavy things regularly you aren't weak because your muscles can't lift that weight. you are weak because your CNS is not used to firing in a coordinated manner needed to activate all the muscle at once. this is where "newbie gains" come from, you aren't changing anything just learning to use what you already have. until you build up this coordination you are literally incapable of actual strenuous exercise.