Often referred to as dumbbell bent-over rows or one-arm dumbbell rows, lawn mowers got their name because when performed they mimic the same movement required to start a lawn mower. The lawn mower exercise is simple, effective and easy to perform, and it targets the entire back. Bodybuilders and weightlifters have included lawn mowers in their back workouts for decades to increase strength and build mass throughout the entire back.
Muscles Used in the Lawn Mower
While you can use the lawn mower as an overall back exercise, it also targets more specific muscles located in the back. This exercise mainly works the latissimus dorsi, teres major, posterior deltoids and the trapezius and rhomboid muscles at the end of the contraction, according Frederic Delavier, author of "Strength Training Anatomy." Additionally, the biceps, brachialis and brachiorradialis receive secondary emphasis during the movement.
Executing the Lawn Mower
You perform the lawn mower while kneeling over a bench. With one knee and your supporting hand on the bench, the opposite hand should grasp a dumbbell from the floor. While maintaining a flat back, inhale and pull the dumbbell as high as possible while keeping your elbow back and upper arm close to your body. Exhale as you slowly return the dumbbell to the starting position and repeat on both sides.
Variations on the Theme
You can use an incline bench to perform lawn mowers. Lie face down on the bench, grasp a dumbbell in each hand and perform an alternating one-arm row. The lawn mower exercise is not limited to just using a dumbbell for resistance; you can also perform it using low-pulley cable machines, resistance bands or kettlebells. Using lifting straps may help you grip the dumbbell better when executing the movement, especially if you have poor grip strength.
More Back Exercises
The back structure is so large and complex, for the best results it is preferable to train the back through several exercises for more complete development. Include additional exercises in your back workout such as wide-grip pull-ups or lat pull downs, T-bar rows or seated cable rows and either dumbbell or barbell shrugs. If you're a beginner, your workout plan should include two to three sets with 12 to 15 repetitions of each back exercise using a light weight. Do not increase weight too quickly; it is essential to practice proper form first before moving on to heavier weights.