[Victor808]

When I was rehabbing a herniated disc, my PT had me doing a lot of front and side planks. To increase difficulty, she would have me do them on unstable surfaces. Start by putting your forearms on a 3-4in foam pad. You can put your feet on one as well.

Increased instability would be items like - upside down BOSU ball, balance your feet on the flat side of a half-roll. or use those air filled flat disks, one under each forearm. It's really good for your core and back. I used to do a couple rounds of a minute each.

I can't do side planks any longer... neither shoulder seems to be able to support my weight. Maybe they'll heal up eventually and I'll be able to do those again.