Core wrkouts are super important in this sport. I recommend buying an ab wheel, and floor sliders - > Amazon.com : iheartsynergee Power Pink Core Sliders. Dual Sided Use on Carpet or Hardwood Floors. Abdominal Exercise Equipment : Sports & Outdoors.
Also a weighted vest. These make great additions to exercises you do anywhere!
Suggest other ideas below.
I'm very much of the Rocky style of rudimental equipment training as opposed to the Ivan Drago super expensive equipment style of training so:
I think that best core workout is rolling and drilling…
I concur that core strength is a must as part all your overall strength and conditioning training outside of BJJ. Having a workout routine, particularly one that involves weight or calisthenics, cardiovascular, HIIT and mobility training, will give you an overall advantage when rolling.
I've strained my lower back a few times (was unable to walk for a week), and what back exercises do you recommend? I tried to shoot for a single leg over a +40 lbs blue belt, but was out for a month after the failed shot.
When I was younger rolling was all that I "needed" lol. However, now that I'm older I definitely need to keep up on my strength training and flexibility. This helps me with BJJ and life.