Stand with feet hip-width apart, hinge at the hips with a flat back and hold a dumbbell in one hand. Let the weight hang straight down. Keeping your core braced, pull the dumbbell up toward your hip by driving your elbow back and squeezing your back muscles at the top. Slowly lower the dumbbell back down under control. Repeat on the other side.
Log your dumbbell single arm bent over row sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.