Locating the Latissimus Dorsi
The latissimus dorsi muscles (lats) are surface muscles on either side of the back. They originate in a wide band that starts at the 7th thoracic vertebrae and goes all the way down to the sacrum (see the sections of the spine). The muscle narrows as it curves upward around the side of the ribs and makes a slight spiral as its tendon (tendons attach muscle to bone) wraps around the underside of the humerus (upper arm bone, attaching at the front top of the humerus in the bicipital grove.
Actions of the Latissimus
The lats, as they are affectionately known in exercise, are primarily shoulder moving muscles even though they appear on the back. They move the arm from the shoulder in three ways: They open the shoulder and take the arm backward - extension. They take the arm closer to the body - adduction. They rotate the arm inwardly - medial rotation.
When the shoulder is in a fixed position, one of the wing-like actions of the latissumus dorsi help lift the mid-section of the torso, the thorax, upward. Pull ups are a well-known example of this kind of lat exercise.
Latissimus Dorsi Exercises
Now that you know how the lats move the body, you can start to picture what kinds of moves create lat exercises. In addition to chin ups, lat pull downs are one of the most popular of the lat exercises. You can see why -- it is a combination of bringing the arms down and in closer to the body as there is an upward lift of the trunk. But chin ups and lat pull downs require exercise machinery and this is a Pilates site. So let's look at how some Pilates mat exercises engage the latssimus dorsi muscle. Pilates is full body exercise; we rarely do an exercise that targets just one muscle but the lats do assist in many exercises.
Many of the exercises we do lying on the mat with the backs of our arms pressed against the floor can be included in this category as well. Though the upper arm doesn't visually move backward, the shoulder is extending and the energy is there. Roll over, shoulder bridge and jack knife are examples.
A little more subtle, but important, are the breadth across the back the lift through the thoracic spine we get from the lats when the shoulder is in a fixed position. You can feel this engagement of the lats in exercises like swan prep, plank and Pilates push up if you press your hands both down and pull back against the floor. There are many more opportunities to experience all of the actions of the latissimus in Pilates equipment exercises. Chest expansion, pull straps, long stretches and long back stretch are examples from the reformer. Than there are Cadillac pull ups, exercises done with the push through bar, Ped a Pull arm work exercises and many more.
Final Reflections on the Latissimus Dorsi
One of the most powerful ways to tune into the lats is to consider how this powerful muscle arises along a length of spine and spirals up and out into the arm, like a wing. As an extensor, it opens the shoulder and arm to the back. As an adductor, it brings the arm and shoulder closer to the body. It also assists in lifting the torso in concert with a stable shoulder. When I consider these kinds of moves, I think of the way a wing might propel a body upward. Liz Koch, an expert on the psoas muscle, suggests that the latissimus is a partner to the psoas with the energy of the lats being up and out and the energy of the psoas moving down. She points out that the psoas is close to the core and takes us inward and the lats are surface muscles that move our energy outward.
Core Awareness Newsletter, Liz Koch, 8/3/2011
Pilates Anatomy, Isacowitz and Clippinger
Anatomy of Movement, Calais-Germain
Structure and Function of the Body, Thibodeau and Patton