There is something wrong with the view on the first floor. Good muscles are as soft as cotton when not in use, but they are also in good shape. When used, it will become rock-solid and the blood vessels will burst. Whenever you say hard, you "die" your muscles because you don't stretch.

I answer your question like this. Different fitness goals need different muscle sensory stages. If you just want to gain muscle, don't hurt yourself. 1 hour of concentrated stimulation is enough. Fat loss training is different, too painful, and I admire how I got through it every time I finished it. If it is only the category of mass fitness, then you are free and it is ok to practice cool.