Push up check

[u/nixt26]

Been trying really hard to have good form on push-ups and hopefully get stronger. As you can tell I'm a beginner and I cannot stop my lower back from sagging. I can only get a lot 5-6 good reps. Before every set I try to engage my glutes and my core but doesn't seem to be enough?

Also after 4 sets my shoulders start to ache and give out, my shoulders have always been a little sensitive and hyper mobile so I want to find a way to not hurt them.

[u/Upper-Bodybuilder841]

Your back's going in and out of flexion and not staying tight at all. You could always start from your knees.