One of the great things about hitting mechanics is that there is always things to learn. Today I want to discuss one of the classic “flaws” in a swing: the arm bar. I want to discuss what an arm bar is and why it is not as evil as most people think about why it might actually be beneficial in the right hitter.
What is an Arm Bar? An arm bar is essentially when the front arm gets locked out or completely straight as the hitter begins to move the hands towards the baseball.
Changing Beliefs In traditional baseball hitting theory, the arm bar is one of the worst possible things that can show up in a hitter’s swing. Even today, it is still one of the more commonly recognized “flaws” that hitters, parents and coaches pick out in a swing. I once believed that an arm bar was a deadly sin in hitting. However, the more I watched certain hitters I was training, the more I began to contemplate if it really deserved to be one of the more demonized things in hitting mechanics. Two hitters that I trained in particular made me dig deeper into the arm bar issue. One was probably the best college hitter that I worked with and the other is a Major Leaguer. Both have had tremendous success and both had a pretty glaring arm bar. This similarity in two high level hitters got me thinking that an arm bar may not be the worst thing in a swing.
Biomechanics of the Arm Bar The first thing that we have to recognize is how energy is transferred up the kinetic chain. When looking at the chain, we have numerous links between segments. To understand more on the kinetic chain, click here. The link that we are interested in when it comes to arm barring is the link between the torso and the front or lead arm. When talking about energy transfer, we are talking about the relationship of stretching and stabilizing certain body parts or muscles with correct timing. In this case, we are going to focus on the Lats. The lats are the biggest muscle in the upper body. They attach to the back of the pelvis and run all the way through the armpit and attach to the underside of the upper arm bone. They are incredibly important to the energy transferring the swing.
Stretch: In order to transfer energy from the torso to the front arm, the lats must get stretched. When the hands are further back, and kept back, the lats get stretched, thus allowing the torso to send more speed to the lead arm.
Deceleration: Deceleration is a huge key to creating power. Essentially, deceleration is when the segment below slows down or stops to make the segment above move faster. In order to make the lead arm move at maximum speed, the torso must decelerate. When the lead arm is barred, two things happen to aid in deceleration of the torso. First, the torso “runs into” the front arm, thus helping to slow down the torso. Second, when the lats get stretched, the lats grab onto the torso and help slow it down.
So, should everyone have an Arm Bar? Like just about everything in the swing, it depends on the player and their unique movement capabilities. When we assess players, we utilize the On Base U screen to determine how well a player moves and what they are able to show in a swing. In order to even think about incorporating an Arm Bar, the player must have adequate mobility through their lats and the rear muscles of the front shoulder. If a player possesses these, then it is a possibility. If a player does not, then an arm bar may cause some issues.
For those of you who would rather watch a video here is a Youtube version of this article: