I'm finding some interesting research about the Frank Starling curve regarding contractile force of muscle cells, which applies to the heart and skeletal muscle. Whether the heart or skeletal muscle, muscles "stretch" based on the load placed on them. So when a heart enlarges too much from too much stress, contractile force of the individual muscle cells of the heart decreases, resulting in a reduced ejection fraction. So marathon runners frequently have a low ejection fraction and an enlarged heart. The individual heart muscle cells are getting weaker despite the amazing aerobics.
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High intensity aerobics stretches the heart beyond the ideal stretching point, the heart enlarges but the contractile force of the actual muscle cells of the heart decreases. If you add anabolic hormones, which also enlarge the heart, to high intensity aerobics, you are doubling down on the lowering of ejection fraction and enlargement of the heart. So it's key to limit cardio while on anabolic hormones.
It's interesting to note that since the Frank Starling curve applies to ALL muscle, it is likely that the contractile force of each bicep cell get WEAKER as the muscle gets bigger, and the increase in skeletal muscle size from HEAVY weight training is actually from satellite cell recruitment, not from individual contractile force in the muscle cells themselves. So the actual mechanism of growth for your biceps from muscular to HUGE, is that as you place an extreme load on the muscle, the force stretches the muscle and it grows satellite cells, but each muscle cell actually gets a bit weaker.
I'm still researching this.