Row Flat Bench One-Arm

A one-arm dumbbell row is a compound resistance exercise, which targets the upper and middle back including the latissimus dorsi, middle trapezius, rhomboids and teres major. This exercise is performed with a dumbbell while kneeling on a flat bench.

The concentric portion of the lift is scapular retraction, shoulder extension, and elbow flexion. The eccentric portion is scapular protraction, shoulder flexion, and elbow extension as the dumbbell is lowered.

The purpose of the one-arm dumbbell row is to strengthen the latissimus dorsi, middle trapezius, rhomboids and teres major, focusing on one side at a time, while also promoting the hypertrophy (increases in size) of these muscles.

One-arm dumbbell rows strengthen and develop muscles of the upper and middle back. This exercise requires less stabilization from the back muscles, abdominals, and legs compared to the bent-over row. Therefore, the one-arm dumbbell row allows the lifter to place grater isolation on the latissimus dorsi, middle trapezius, rhomboids, and teres major as the scapula retracts.

The bench supporting the body weight also omits the factor of low back fatigue that can occur with dumbbell bent-over rows. This position may accommodate to lifters with a compromised back.

One-arm dumbbell rows allow the lifter to execute scapular retraction and shoulder extension one arm at a time. This allows the lifter to focus on each side, individually, and may also help determine any weaknesses, if any.

The one-arm dumbbell row places greater emphasis on shoulder extension and less emphasis on scapular retraction compared to the mechanics of a bi-lateral bent-over dumbbell or barbell row. This places greater emphasis on the latissimus dorsi.

In addition to serving as an exercise that enhances the aesthetics of the upper and middle back, one-arm dumbbell rows also complement weightlifting and sport performance.

The latissimus dorsi is a broad, flat, and triangular-shaped muscle of the lower back. When defined, the “lats” form a “v” shape of the torso as they angle toward the waist. The latissimus dorsi is a primary shoulder adductor and shoulder extensor. In this exercise, the latissimus dorsi is responsible for extending the shoulder as the dumbbell is lifted upward. Its origin is located along the spines of the lower six thoracic vertebrae, lower 3 to 4 ribs, and iliac crest of the pelvis. Its insertion spirals around the teres major as it inserts into the intertubercular groove of the humerus.

A flat and triangular muscle, the trapezius is the most superficial muscle of the posterior thorax. The middle fibers run horizontally to the scapula. Its origin is located at the occipital bone, ligamentum nuchae, and spines of C7 and all thoracic vertebrae. Its insertion is located along the acromion and spine of the scapula and lateral region of the clavicle. The middle trapezius retracts the scapula. As a superficial muscle, developing the middle trapezius contributes to the overall aesthetics of the upper back.

The rhomboids are two rectangular muscles that lie underneath the trapezius just below the levator scapulae. The rhomboids consist of the rhomboid minor and rhomboid major. The rhomboid minor is located above the rhomboid major and is more superficial. The origin of the rhomboid minor is located at the spinous processes of C7 and T1. The origin of the rhomboid major is located at the spinous processes of T2-T5. The insertion of both rhomboids major and minor is located at the medial border of the scapula. The rhomboids are synergists with the middle trapezius when retracting the scapula.

The teres major is a thick muscle located underneath the teres minor. It helps to form the posterior wall of the axilla. A synergist of the latissimus dorsi, the teres major extends the shoulder in this exercise. Its origin is located at the posterior surface of the scapula at the inferior angle. Its insertion is located at the crest of the lesser tubercle on the anterior humerus (its tendon fused with that of the latissimus dorsi).

The deltoid is a thick, multipennate muscle that forms a curtain around the shoulder. It is the primary muscle involved with arm abduction. When developed, the deltoids give the shoulder their round shape. The extension of the shoulder joint as the dumbbell is lifted activates the posterior fibers of the deltoid. The origin of the deltoid is located at the insertion of the trapezius, lateral third of the clavicle and the acromion spine of the scapula. Its insertion is located at the deltoid tuberosity of the humerus.

The biceps brachii consists of two heads, the long head and the short head. The long head tendon helps stabilize the shoulder joint and its origin is located at the tubercle and lip of the glenoid cavity of the scapula (shoulder blade). The short head origin is located at the coracoid process of the scapula (shoulder blade). The long and short head unite as the muscle bellies run down the front of the arm. Both heads merge, sharing insertion into the radial tuberosity of the elbow joint. The biceps brachii flexes the elbow joint as the dumbbell is lifted upward.

The brachialis lies underneath the biceps brachii, originating at the front of the lower end of the humerus bone. Its insertion is located at the coronoid process of the ulna at the elbow joint. The brachialis is a primary elbow flexor.

The quadratus lumborum, iliocostalis, longissimus, spinalis, and semispinalis play an essential role in stabilizing the neck and upper and lower regions of the back during this exercise as the torso is in a flexed position.

The abdominal muscles, rectus abdominis, external oblique and internal oblique also play an important role in stabilizing the torso.

The hamstrings (i.e. biceps femoris, semitendinosus, semimembranosus) and quadriceps femoris (i.e. rectus femoris, vastus lateralis, vastus intermedius, vastus medialis) assist in stabilizing the torso from the lower extremity.

The rotator cuff muscles help stabilize the shoulder joint as the scapular retract and the shoulder extends. The wrist flexors maintain the wrists rigid and stabilized throughout the exercise.

Dumbbell bent-over rows, barbell bent-over row, bench rows, T-bar rows, seated rows, standing one-arm low-pulley rows, machine rows.

Performing this exercise bi-laterally (e.g. dumbbell bent-over rows, barbell bent-over rows, seated rows) will complement strength gains achieved from performing one-arm dumbbell rows.

Performing row exercises unilaterally and bilaterally (with varying grip positions when performing bilaterally) optimizes muscle fiber activation of the muscles involved. Over time, and strategic variation with your back training regimen, this enhances muscle hypertrophy and strength of the upper and middle back.

Focus more on the shoulder extension and scapular retraction to lift the dumbbell upward as opposed to focusing on the hand dominating the effort of the lift. This will not only optimize muscle activation, but also prevent strain on the biceps brachii that could increase the risk of injury.

Focus on the concentric portion of the contraction, concentrating on “squeezing” as the upper arm reaches the level of your torso.

Emphasis on eccentric contractions, prolonging the eccentric portion of the contraction, may also be incorporated in a training program focused on increasing strength. This should be implemented accordingly and with adequate muscle recovery as eccentric contractions cause substantial damage to muscle tissue.

It’s important to note that your repetition and set volume will depend on your goals (e.g. strength, hypertrophy, muscular endurance). It is also important to allow adequate recovery days in between back, shoulder, and biceps training days to allow muscles to repair.

Using momentum to lift the dumbbell (e.g. jerking the torso for assistance) minimizes the potential of force production of the involved muscles and can increase the risk for injury. It is important that both the eccentric and concentric phases of the exercise are controlled.

If the lifter has a compromised range of motion with the back or shoulder joint and/or performs this exercise incorrectly, this exercise can increase the risk of injury and/or exacerbate a previous injury.

If proper technique and recovery are not adhered to, impingement syndrome, rotator cuff injuries, and/or lower back injuries may occur.