You can HIIT row, see Apple Fitness+ if you can stand the wellness vibe. But if you want challenging, join the Concept2 challenges. I was doing 10k rows severa

You can HIIT row, see Apple Fitness+ if you can stand the wellness vibe. But if you want challenging, join the Concept2 challenges. I was doing 10k rows several times a week as a middle-of-the-pack competitor and if that doesn’t challenge you then you should go pro. But as I mentioned in another comment, you can injure yourself on a Concept2 if you don’t cross-train. It’s not a magic device.