Please, do not “relax” when someone is spotting you. The spotter is there to
help you move the bar, not take the entire weight themselves! It’s fine for male MC here because he could probably lift 35kg with one hand, but not good to do normally.
So, like, outside of the manga: always have a spotter, especially if you're going for a new weight.
It’s not 100% necessary, but it does bring peace of mind. If you are not going to have a spotter on the bench, however, please do NOT clip the ends of the barbell like she did here. You will not be able to dump the weights if you get pinned by the bar, and death may occur.
I am no expert on weightlifting, but holding the dumbbell differently with both hands seems kind of unhealthy.
Acktually, it’s a barbell, not a dumbbell ☝️🤓
If you see this grip in the gym, it is likely someone deadlifting. It is called “reverse grip”. It has its pros and cons. You should probably not use it for normal strength training. The grip is fine in this instance. He is helping her lift a relatively light weight. No danger.