Strength and Conditioning for Baseball Part I

Posted: March 21, 2014 in Uncategorized
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Shoulder and elbow injuries are far too common in throwing athletes.  Approximately 1/3 of pitchers between the ages of 9 and 18 suffer a pitching related injury.  With injury rates that high we are all failing the athletes that play America’s favorite past time.  I played baseball competitively up until I was 18 years old and I cannot remember one time a coach teaching me how to properly throw a baseball.  From a mechanics standpoint, throwing a baseball is an extremely complex task.  In order to understand it we need to understand a few basic movement principles.

Our shoulder joint is a complex structure made up of 3 bones: the humerus, scapula, and clavicle.  The head of the humerus sits in a socket-like structure on the scapula called the glenoid cavity.  This is known as our gleno-humeral joint (GH).  Surrounding muscles and connective tissue are responsible for keeping the head of the humerus in the glenoid cavity.  Any miscommunication or imbalances between these muscles can lead the humeral head to move improperly in the glenoid cavity.  

The rest of the scapula sits on our thorax and this is known as the scapulo-thoracic joint (ST).  During GH movements the scapula should move smoothly along the thorax.  According to Sahrmann, clinical observations suggest that most syndromes of the shoulder arise from impairments in the timing and control of the scapula (Sahrmann, 2002).  The scapula’s normal alignment should be 3 inches away from the spine between t2-t7 with the medial border (border closest to the spine) parallel with the spine. 

During 180 degrees of shoulder flexion we need 60 degrees of upward rotation of the scapula.  If we have inadequate upward rotation of the scapula and weakness in the two rotator cuff muscles, the infraspinatus and teres minor, that are responsible for pulling the humeral head down into the GH joint when the arm is flexing overhead, we will experience impingement.  Neer described in 1972 a continuum of shoulder issues that begins with impingement and ends in rotator cuff tears.  Also, if our scapula is not aligned appropriately from the start then it will alter actions of the shoulder.  For example, an athlete has tight rhomboid muscles that cause the scapula to start in a downwardly rotated position then it will require greater then 60 degrees of upward rotation to counteract that faulty alignment.  This too can lead to shoulder injuries down the road.

In order for our scapula to function properly we need adequate thoracic mobility.  Postural malalignment such as forward head and excessive kyphotic curve of the thoracic spine lead to malalignment of the scapula, which leads to dysfunction.  A literature review of 150,000 articles concluded by stating that we need to understand the kinetic chain in order to fix dysfunction of the shoulder (http://www.logan.edu/mm/files/LRC/Senior-Research/2011-Aug-12.pdf).

In a nutshell the kinetic chain is how all of the muscles in our body are integrated.  Muscles communicate with one another and the brain through fascial attachments.  Fascia are sheaths of connective tissue that actually contain contractile units, neurons, and blood vessels.  They are the electrical component of the human movement system.  When muscles become weak or injured the fascia, through two-way communication with the brain, will have other muscles take over and do extra work.  This is how movement impairment occurs.  However, the dysfunction does not end there.

We need proper ankle mobility, knee stability, hip mobility and stability, lumbar stability, thoracic mobility, scapula stability, GH mobility, and cervical stability.  Let us look at a common scenario.  We sit down all day long which leads to shortened hamstrings and weak glutes.  Our glutes are our strongest hip extensors, but in this scenario our body will begin to use the hamstrings as the primary hip extensors due to their shortened state and the weakness of the glutes.  This causes our pelvis to be pulled down and away from the lumbar spine causing back pain.  Then we decide to go for a run after work.  From sitting all day glute medius becomes weak.  Our fascia and brain communicate this and this leads to another muscle, our TFL, becoming overactive.  Our TFL inserts into our IT band, which then inserts into our knee.  When overactive our TFL can cause anterior shear forces on the knee and we suffer from anterior (front) knee pain.

Let us look at our youth baseball players.  They sit down hunched over a desk all day at school and then come home and assume a similar posture to watch TV and play video games.  This leads to infraspinatus and teres minor becoming elongated and weak, internally rotated humeral head, increased kyphotic curvature of the thoracic spine, shortened hamstrings, and weak glutes.  This prolonged posture alone is going to lead to both shoulder and hip dysfunction.  From there they go to baseball practice and repeatedly practice this dysfunction without ever being coached.

They then enter the gym and bench press, perform bicep curls, and tricep extensions to strengthen their shoulder and elbow muscles.  The problem is this is not how these muscles are integrated to work together during a throwing motion.  We first integrate these muscles together during crawling.  They all work together to pull the torso and scapula over the stance arm supplying balance.  Now think of the lead arm while throwing.  They play important roles with the rotator cuff muscles to stabilize the scapula and pull the humeral head into its proper place in the glenoid cavity.  In the throwing arm we need the same support from the surrounding musculature.  The pecs then help stabilize the spine and aid in torso rotation to throw.  If we have tight pecs or an internally rotated humeral head it will limit our ability to externally rotate our shoulder properly, lead to dysfunction and asymmetry in rotation and in time we will develop injuries.

We also need proper timing between the deltoids and rotator cuff.  The rotator cuff muscles need to fire first to pull the humeral head into an optimal spot.  Front raises and lateral raises are popular exercises being done in the gym for the shoulder.  When infraspinatus and teres minor become weak the supraspinatus (another rotator cuff muscle) has to pick up the slack.  This will lead to impingement and down the road a rotator cuff tear.  All this athlete is doing in this scenario in the gym is further engraining their dysfunctional movement.

This does not even begin to scratch the surface of what can go wrong in throwing a baseball.  Breathing, eye position, the anterior and posterior oblique chains, deep longitudinal system, and lateral system all play critical roles in the complex movement of throwing a baseball.  We will dissect all of these as well as throwing mechanics in upcoming articles.

 

 

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