Description

The main muscle group worked during the single-arm row is the latissimus
dorsi (lats). You also engage the entire back, shoulders, and arms (the
trapezius, rhomboids, teres major and minor, deltoids, infraspinatus,
biceps, brachialis, brachioradialis, and even pecs).

Execution

• Take one step back into a lunge position. Keep a soft bend in your front leg
  with the knee in line with your ankle and back leg straight. Lean slightly
  forward, and rest your free hand on your front thigh. Tighten your core by
  squeezing your belly button in towards your spine. This will give you a good
  base of support.
• Lower the dumbbell toward the floor until you have a full extension at the
  elbow. Maintain proper posture through your shoulders, hips, and lower
  back. Avoid rounding or arching the lumbar spine.
• Begin the upward motion of the dumbbell by first sliding your shoulder
  blade toward your spine and then lifting the weight up toward your torso by
  driving your elbow to the ceiling. Keep your elbow close to your body as it
  passes the ribs.
• Squeeze your shoulder blade in toward the center of back (contracting the
  rhomboids). At the end of the movement, the dumbbell should be in line
  with your chest and your elbow should be pointing up toward the ceiling. Be
  sure to maintain good posture through your spine, shoulders, and hips.
• Repeat for the appropriate number of repetitions.
• Switch sides and repeat the same number of repetitions with the opposite arm.
• Perform two to three sets of the exercise, with a one-minute rest between sets.