Do them against the wall, working your way to the floor.
Put a band around your hips, to an anchor point and back bend into a wrestlers or gymnast bridge, and back up for reps or time. Progress by moving the anchor point down, move closer to the anchor point, and lights bands.
Handstand extensions. Face away from the wall, and kick up into a hand stand. Move further, and further, or walk away from the wall. Extend the t spine, lock the arms, and keep everything else tight. I saw a video of Adam Glass doing these and I like all handstand variations.
Do them over a yoga/Swiss ball.
Do them on your toes, working to flat footed.
Reverse push-ups. Press for reps from your head on the floor to locked arms.
I am sure there are other options, but these are things I have used. Gymnast and wrestler bridges are great.
I´ve been wondering about the back bridge. What do they do to the body? Are they safe and something that one should be aiming to do? My lower back/hip joint is wrecked and someone said that bending back like that could be good?
I believe they are 'safe' if done correctly and eased into. (Like virtually any other training modality)
However!!! If your lower back/hip joint is wrecked as you put it, then you should seek professional medical advice on any and all training that could impact this area. Get this sorted out first before considering back bridges. Just my opinion.
Back bridge variations link the anterior and posterior torso together, and are a powerful postural exercise. Many back problems, hunched impinged shoulders, and tight hamstrings and calves are caused by a tight anterior chain pulling the hips into anterior tilt or the duck butt posture. This causes the tension on the posterior chain, reducing range of motion, and an excessive arch in the low back.
Back bridge variations really stretch and strengthen the anterior chain relieving the issues above, and are a good antigonist exercise. Pavel states in one of his books to do back bends between sets of swings. Weightlifters have know this forever.
Between sets of posterior chain exercises do a back bridge progression. Between sets of swings I will sometimes do a few banded wrestlers bridges, or gymnast bridges against the wall for time. They work great between warm up sets of presses, and will improve your get up also. They will really improve the arch, and leg drive for bench pressing. I feel they are critical to create balance in the body. They are a great cool down paired with hangs, and diaphramatic breathing.
To stay safe practicing back bridge variations use the same rules for any other exercise. Use common sense and do not force a range of motion you are not ready for.