These will challenge you more than any dumbbell row. You'll be essentially rowing your bodyweight with one arm.
Don't let your shoulder shrug up, keep your core braced, and pull with control. You'll feel your core work double-time to stabilize the offset load. Your pulling muscles will also contract deeply. To make it easier, simply go flat footed or adjust your angle.
Chances are if you're over 30 that backside of yours is starting to look like two gluten-free pancakes, even if you train. Here's why and how to fix it.