Iron Man December 2008 Excerpt: Lock And Load Your Lats!

By understanding how the lats are shaped, its connection to the skeleton and its function, you can make every workout twice as productive. Here' an excerpt from Lock & Load Lats in the January 2009 issue.

Lock And Load Your Lats
Harmony Of Structure And Function For Width-Building Contraction

Anyone who's taken a class in the life sciences has heard the phrase "structure equals function." That applies in the gym, and it applies to building muscle, a prime example being the lats. By understanding how the latissimus muscle is shaped, its connection to the skeleton and its primary function, you can make every workout twice as productive.

The back is composed of dozens of muscles, and there's no way to isolate any specific one, nor will any particular set of exercises add thickness over width or vice versa. Many of the deep muscles in the back, however, are stabilizers of the spine and trunk, so when you work your lats with heavy free-weight exercises, you indirectly stimulate them all.

arrow Structure:

    The latissimus dorsi is a large fan-shaped muscle that covers those dozens of other muscles. It starts in the back at vertebrae T5 through T7. It fans across the lower three ribs, to the iliac crest, or hip bone, and to the inferior angle of the shoulder blade—a big fan indeed—finally running up under the armpit and reaching around your arm between two small bumps called the intertubercular groove. That's at the top of the upper-arm bone, or humerus, very close to the ball-and-socket joint where arm meets shoulder. The long head of the biceps muscle runs right over that, and the short head runs right alongside.

    Obviously, biceps recruitment is inevitable when you're working the lats. You can see that trying to cut the biceps out of the picture with various hand placements is a moot point. To be quite honest, trying that kind of thing will only lessen the amount of stimulation your lats get. For the elbow to bend, the biceps must contract. It's that simple.

    If you study anatomy, you'll recognize that muscles are meant to work together, and you should keep that in mind when you design a workout.

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arrow Function:

    Understand that a muscle contraction is a shortening of the fibers and that for the most part they shorten in the direction of insertion to origin.

    The job of the lat is to pull the arm down and back and keep the elbows close to the body. The lats also draw the shoulder inferiorly, which means that if you extend your arms overhead as high as you can, as if you were stretching, you can pull your arm down about two inches without actually bending it.

    You're pulling your shoulder toward the ground with lat contraction. The lats pull down if your arms are up, and they pull backward if your arms are down.

    Think of a bodybuilder going into a rear lat spread. The first thing he does is flex his lats to bring out the lower-back "Christmas tree." How does he do that? By pulling his shoulders down and back and drawing his elbows back, keeping them tucked in close to his body.

arrow Effective Training:

    Effective lat training is simple in theory, but it's a little harder to actually do it. I trained for years before I actually felt back exercises in my lats. I'd bet there are more than a few of you in that boat right now.

Get the full article in the December edition of Iron Man Magazine.

Editor's note: For more articles by Eric Satterwhite, visit IM