Kneel beside a cable machine with the cable set low. Lean slightly forward and grab the handle with one hand. Keep your chest up and core engaged. Pull the handle toward your torso, squeezing your back muscles. Slowly return to start with control and repeat for reps, then switch sides.
Log your cable kneeling leaning forward one arm row sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.