The latissimus dorsi, commonly known as the lats, are the largest muscles of the upper body, forming the wide, triangular shape of the back. Developing the ability to flex these muscles on demand is an objective for many individuals focused on fitness and physique development. This skill improves the mind-muscle connection, which is the intentional focus on a specific muscle during exercise to maximize its activation. Learning this voluntary control enhances the neurological signal sent from the brain to the muscle, ensuring the lats are the primary workers during back exercises. This focused engagement drives more targeted muscle development and improved functional strength.
Identifying the Latissimus Dorsi Muscle
The lats are expansive, originating from a wide area of the lower and mid-back, including the lower six thoracic vertebrae, the thoracolumbar fascia, and the iliac crest. From this broad origin, the muscle fibers sweep upward and insert on the humerus, or upper arm bone, near the shoulder joint. The muscle’s function is primarily to adduct the arm (bring it toward the body), extend the arm (pull it backward), and internally rotate the arm.
To locate and feel this muscle, stand upright and place a hand on the side of your torso, just below the armpit and rib cage. Try a light cough or slightly move your arm backward against gentle resistance. You should feel a thick band of muscle tightening and bulging under your fingers; this is the latissimus dorsi contracting. This tactile identification establishes sensory feedback, linking the physical location to the feeling of activation.
Achieving Isolated Lat Contraction
Achieving an isolated lat flex requires focusing on the actions the muscle performs on the shoulder and scapula without using the arms to pull anything. Begin by assuming a tall, relaxed posture with your feet hip-width apart. The movement starts with the shoulder blade, focusing on scapular depression—pulling the shoulder blade down toward your hips. Simultaneously, perform a slight retraction, moving the shoulder blades gently toward the spine.
The mental cue that often simplifies this action is the “armpit squeeze.” Imagine you are trying to clamp a tennis ball in each armpit by pulling your elbows down and slightly inward toward your sides, without actually bending the elbows or moving the forearms. This internal focus on driving the humerus down and back initiates the lat contraction, causing the muscle to tense and flare out slightly from the rib cage. The isolation is successful when you feel a deep tension along the side of your back, and your biceps or upper trapezius muscles are relaxed.
A common error is shrugging the shoulders, which activates the upper trapezius and negates the intended lat isolation. The key is to keep the shoulders low and away from the ears, maintaining the depressed scapular position throughout the flex. Practice this isometric contraction by holding the tension for three to five seconds, concentrating on the feeling of the muscle fibers activating. This static practice teaches the nervous system to bypass compensation-prone muscle groups and target the lats directly, strengthening the neural pathway.
Applying Lat Flexing to Training
The isolated control developed through flexing can be directly translated to dynamic pulling exercises in the gym. Before initiating any repetition of a lat pulldown or a row, a brief pre-flex, or “pre-tension,” should be performed. This involves pulling the shoulders down and back to engage the lats just before the weight starts moving. Engaging the lats first ensures they are the primary movers in the exercise, preventing the smaller biceps or the upper back from taking over the load.
In exercises like the cable row, the movement should be driven by the elbows, imagining they are being pulled toward the back pocket, not by pulling with the hands. This focus on the elbow path is a functional application of the armpit squeeze cue, maximizing the lat’s role in arm adduction and extension. Similarly, during a pull-up or lat pulldown, the initial motion is the downward pull of the shoulder blades before the arms bend, which is known as scapular depression.
This technique is most impactful at the beginning of the movement and during the peak contraction phase, where a squeeze enhances muscle fiber recruitment. Using a lighter weight initially allows for a greater focus on feeling this connection and ensuring optimal form. Over time, this pre-tension becomes automatic, leading to better overall back development and greater efficiency in all pulling movements.