I used coach Nicole's video and she stressed pull in the abs when walking. Many rainy days I did not walk outdoors. I did videos they are not so easy to pull in abs.
I was doing an exercise at the computer and realised my abs are much tighter. Now i sit at the computer and lean back and keep the abs tight and it is helping me and easing the pain in my lower back Woohoo. It helps me I hope it might help you too.