Holding a dumbbell in each hand using a neutral (hammer) grip, stand with your feet shoulder-width apart.
Keeping a natural curvature of your spine, flex your hips and knees until your torso is horizontal or close to horizontal.
Allow the dumbbells to hang down by your sides, with your shoulders stretching downward.
Execution
Keeping your elbows close to your body, exhale as you pull the dumbbells up to the sides of your waist.
Hold for a count of two and squeeze your back muscles.
Inhale as you lower the dumbbells to the starting position, with your shoulders stretching downward.
Repeat.
Comments and tips
Keep your neck level and head up, and try to maintain a natural curvature of the spine.
Pull with your elbows, not with your biceps.
Keeping your torso horizontal (or close to horizontal) and your elbows tucked in will ensure that you activate the right muscles.
The bent-over two-arm dumbbell row is great for developing upper-body strength once you master form and are able to go heavy. However, start light to allow your lower back time to adapt.