I injured my shoulder a while ago, so to modify for planks and side planks in workout classes, I came up with some alternative core strengtheners on the ground that didn’t involve shoulders. This was what I created for a side plank alternative!
It definitely engages your side core muscles equally, if not more than, a side plank and also has an added balance challenge. It is funny to watch yourself in a mirror while you do this, hence I have named it the “floppy fish” - although of course you want to be controlled in your movements, and not floppy!
Start by lying on one side with your body in one long straight line from your head to toes. The biggest challenge here is to balance on the bottom side of your body and avoid the temptation to bend at the waist for more stability - especially if you try the challenge option at the end of the video! You can support your neck with your bottom arm. Engage your side core muscles to lift your legs and upper arm, imagining that they are being pulled together, and lower back to the ground with control.
If you find it difficult to maintain your balance, try starting by keeping the lower leg on the ground and just lifting the top leg for now. For a challenge, straighten both arms up overhead and lift your upper and lower body off the ground! Perhaps even try to hold it for a few seconds!
Let me know if you try this and what you think! Be sure to do both sides!