First of all, you can be sure that when you are elected, your back is arched into a bridge. Simply put, it's a little excessive, so it will put too much pressure on your lower back.

Well, I forgot to ask, are you standing or sitting?

As long as the seated person leans back on the back of the chair, it will be all right without excessive bending.

If you are standing, you must use a weightlifting belt. This gym is usually provided free of charge.

There is no substitute for pushing, and the instrument has no such effect. I suggest you do the sitting dumbbell push with the correct posture.

Practice at home, I don't know how much your dumbbells weigh.

If you don't have a belt and a suitable chair, you must use a small weight to keep your back from bending, but the effect will not be very good. After all, this is a compound action, which is very heavy, but it must be done for safety.

I suggest that when you practice your shoulders, you should not give priority to recommendation, but mainly practice pre-lift, side lift and prone lift, which can also fully stimulate the deltoid muscle. If you use the joint super group, the effect will be very strong.

In addition, there is another way to practice shoulders called Parker push-ups, which is probably handstand push-ups who bends down, but I have never tried it. I don't know if it's good.

Why not put a board on the back of the chair? That's ok, as long as there is a support, it's much better.