The Banded Good Morning exercise is a great exercise to engage the deep core muscles and the erector spinae muscles you use to keep yourself upright for paddling. The goal is to, with the band under the feet, pivot over from the hips, with the other end of the band held at chest level. From this position, you want to gradually push the arms up and overhead a small amount. the load will increase on your lower back and extensor muscles. There are three stages to this exercise:

Part 1: Static holds- working on the stability aspect, good for acute injury recovery. push the band up and away from the body and hold at the point of small discomfort. You can also experiment with bring the arm out laterally a bit to explore different ranges of motions to load one side of the spine a little more than the other

Part 2: Strength- Starting to add a little more load and add some slow movement to the exercise. Taking the arms through full range.

Part 3: Power- Start adding fast velocity movements into the mix.

If you can comfortably do part 1 with minimal pain, then you progress to part 2, and so on to part 3.