The latissimus dorsi (lat) is a functional anatomy workhorse.
The average training science textbooks will tell you that it adducts, extends and internally rotates the glenohumeral joint.
Due to the attachment on the inferior angle of the scapula it can also pull into downward rotation, depression and adduction.
Read a little wider and you’ll learn how it plays a role in spinal stability, respiration, gait and transferring force from the lower to upper body.
Evidently having good latissimus dorsi function and strength is important for functional movement and performance.
But how strong is strong enough? And is there such a thing as too strong?
A strong, stable shoulder relies on balance and by that, I mean appropriate relative strength of all the musculature acting on the glenohumeral and scapulothoracic joints.
Strong, powerful lats can be a real asset in the athletic toolbox. However, if all that strength starts to dominate the smaller musculature tasked with joint stability, you’re going to find the lats pack enough punch to bully the shoulder into some less-than-optimal positions.
In an applied context, I rarely see any personal coaching clients who have weak lats. The main problem is that often they can’t get it to moderate its contribution to functional movement. It just wants to work, all the time. Typically, because that’s what it has been asked to do due to sub-optimal shoulder kinematics and kinetics.
Here are two ways the lats can have a negative effect on your shoulder performance and what to do about it.
Front to back balance
People often think of the lat as a ‘back’ muscle, which makes sense. However, if we follow the muscle architecture, we see this big slug of a muscle spans from the pelvis and lower two thirds of the spine up and across to the anterior aspect (front) of the humerus.
Functions of the lat include internal rotation and extension of the glenohumeral joint, imagine being put in handcuffs.
Over dominance can therefore contribute to a sub-optimal position of the humeral head on the glenoid fossa when, for example, it effectively overpowers the posterior cuff.
As a consequence, we can see limitations in overhead range of motion, poor movement quality, co-ordination, rhythm and timing, and therefore, and of significant importance, dynamic stability.
Three ways to improve the front to back balance of your shoulder
To restore balance around the shoulder, think about including the following in your training programme:
1. Improve range of motion in the latissimus dorsi using self-myofascial release and mobilisation techniques
2. Increase the strength and capacity of the posterior cuff through exercises targeting external rotation
3. Adjust your training programme to include a bias on horizontal pulling over vertical pulling exercises.
Top to Bottom Balance
A lot of lat focused work can create a downward pull on the scapula and shoulder. This is sometimes evident in clients who train a lot of pull ups, deadlifts and heavy carries and then struggle to get into good overhead positions.
Every action has a reaction. So, if we neglect to balance the downward pulling forces with enough strength to hold the shoulder in an optimal vertical position, we can run into some issues.
This could manifest in pain pressing overhead because of a change in the scapula position and its ability to upwardly rotate.
Three ways to improve the top to bottom balance of your shoulder
1. Get some range of motion. The same applies from top to bottom as it does from front to back. Mobility is a fundamental component of high-quality shoulder movement.
2. Select exercises that improve upward rotation of the scapula. Serratus anterior, lower and upper fibres of trapezius. These guys are your friends when it comes to getting the scapula up and around the ribcage where the lat wants to retract and depress.
3. Do some upper trap strength work to help with vertical positioning of the shoulder. The caveat however is that it needs to be done in a way that supports point number 2. Monkey shrugs are a good option for this.
So, to answer the question, how strong is strong enough?
Well, you can go as strong as you like or as you need to in order to perform well at your movement or athletic goals.
The important thing to remember is that all that force production needs to be balanced with appropriate strength in the musculature that counters the potential negative effects of a dominant lat.
Strength is good. But it is nothing without range of motion and dynamic stability.
In the video below, we take an anatomy deep-dive into the latissimus dorsi and get a grapple on a few basic problems which can occur.
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