Customized Mechanics: Mobility

In part two we covered the role that antropometrics can play in creating customized mechanics.  The next logical piece is to look at mobility because having long bones is great but if we don’t have enough mobility we lose out on any leverage that the skeletal system can generate.

Mobility/flexability/range of motion should be measured anyways since it useful in screening athletes from future injury.  Pre-season range of motion (ROM) testing along with other screens like Functional Movement System (FMS) are the norm when you get to higher levels of baseball with medical staff personal (i.e athletic trainers).  The sad thing is that the information gathered here doesn’t get shared and discussed with the skill and/or strength coach which means that a lot of great information is lost since most organizations don’t bridge these gaps. Connecting these dots and creating a means of communication would be the role of a sport scientist but unfortunately this role isn’t very common in the baseball world.

There is no question that you need a great deal of mobility to throw hard which is why baseball gets more than its fair share of “flexible” athletes.  Look at some of the positions these professionals get themselves into in order to generate power.

Lots of mobility in the adductors/groin in the above picture and tons of shoulder external rotation and t-spine extension in the picture below.

We will find however that more isn’t always better like we did when we spoke about limb length.  Having a ton of mobility is great because it gives you the POTENTIAL to throw harder but every pitcher must be able to control this range of motion.  If fact there is #controlyourself on Twitter started by Dr. Andreo Spina who created the Functional Movement Seminars which have caught on like wild fire in the MLB.  Many teams have invited either Dr. Spinea or his top instructor Dr. Micheal Chivers from Baseball Performance Group to educate their entire medical staff on this system to help create healthy and powerful athletes.  This is at the top of my continuing education wish list!!

Mobility – How Much Do We Need?

The amount of mobility that each pitcher needs will depend on other parts of their physical profile.  If you have a really big and strong pitcher they might not need to display yoga like flexibility to throw really hard.

To help explain this idea a bit better here is a quote I’ve used in the past.

“The longest possible acceleration should be employed, but the coach should always take into consideration the athlete’s mobility and strength.  The range should be that through which the athlete can reach maximum release speed, which is not always the greatest range.”

This quote came from the track and field world who are the best at developing customized mechanics and training.  So maybe a really long stride or trying to get a ton of hip and shoulder separation might not be the universal answer for everyone.

Here is another great quote that will help explain this idea.  It is from the same article I wrote back in 2013 about what we can learn from Shot Put athletes.  Check it out HERE.

“A world class thrower will exert his strength and speed (FORCE) over a great a range as possible (DISTANCE) in order to achieve a good throw (WORK).  He must ensure that his force is applied for the longest period possible and therefore:  FORCE  X  TIME  = IMPULSE”

The impulse can then be increased in one of two ways:

1) lengthen the TIME that we can apply force (long levers, increase mobility, proper mechanics)

2) apply more FORCE for the same amount of time (get stronger and more explosive)

In knowing this we can look at each of our pitchers to see where they stand to benefit the most from the time and energy they have to dedicate to their training.  If someone is already pretty flexible then maybe they should go lift some weights.  While the pitchers who are “strong as an ox” might need to use a foam roller and stretch.

Athletes don’t like to do what they aren’t good at which is why strong but tight guys don’t like to stretch while flexible but weak guys don’t like to hit the weight room.  Our job as a coach is to identify these weaknesses and address them by ensuring that the athlete does what will make them better.

How Do You Measure Mobility?

Below are some things that I would measure.  Please take note that some of them require skill and expertise and might not be in your “tool box” as a coach.

  • Shoulder Internal and External Rotation
  • Hip Rotation: External and Internal
  • T-Spine Rotation
  • Thomas Test
  • Ober Test
  • Ankle Dorisflexion
  • Shoulder Flexion
  • Functional Movement Screen
  • Beighton Scale

Again this is not an exhaustive list but I can justify taking the time and energy to run players through this list of tests.  As I continue to learn I am sure that this list will change.

The good thing about mobility however is that it is trainable, unlike limb length.  Spending time with foam roller and a yoga mat can do wonders for some guys.  We won’t go into the specifics about exactly what kind of scores you want to find in each test and how to gain mobility, if you need it, here since that is worthy of numerous blog posts.

Too Much of a Good Thing?

When we test our athletes for mobility we are looking for their Range of Motion.  The word “Range” leads to the idea that there are numbers that fall out of this “range” because they are either too small or too big big.  If you follow Eric Cressey at all, he has gone on record many times saying that stretching isn’t for everyone and in fact you might be doing some players a disservice.

In the best paper that I have come across this subject Dr. Andrew Robb conducted a research study where they looked at the relationship between hip mobility and the biomechanics and throwing velocity of professional baseball pitchers.

In this study he makes the following remark which really sums up the point I am trying to get across.

“Previous research has indicated that there are both upper and lower limits to each bio-mechanical angle measurement that correlate to optimum performance and safety.” (1)

Dr. Robb then gives the following example of how too much or too little hip rotation can lead to a decrease in performance while increasing the chance of injury.

“If an excessive amount of rotation occurs at the hips, then the pelvis and foot are in a more open position, thereby prematurely initiating the arm-cocking phase and the resulting in the loss of kinetic energy from the lower extremity.  This would result in greater torque being generated at the shoulder with less energy from the lower extremity” (2)

And in regards to not having enough mobility:

“if hip rotation is smaller, closed positions at the foot and pelvis occur and the pitcher is forced to pitch across the body, which would limit the kinetic energy transfer from the lower extremity to the arm.”(2)

In another study looking at cricket throwers researchers looked at both the role of rotational mobility and power on throwing velocity and wrote this at the end of the abstract.

“It was conclude that greater ROM at proximal segments, such as the hips and thoracic, may not increase throwing velocity in cricket as reduced ROM at proximal segments can be useful in transferring the momentum from the lower extremity in an explosive task such as throwing.” (3)

This was a study using cricket players however the style of throwing that they used was more of a “baseball” type of throw that you would see during fielding rather than the locked elbow you see from the bowlers.



Mobility is vital for both health and performance.  Baseball requires a minimum level of mobility for both performance and injury prevention which is why the idea of stretching is a staple at any level of baseball.  The idea that I really wanted to get across is that in order to succeed your mobility must fall within an acceptable range.  Where each player needs to be in within that acceptable range is the big question that can only be answered when we look at other parts of the physical profile.

Graeme Lehman, MSc, CSCS


  1. The Relationship between age and baseball pitching kinematics in professional baseball pitchers – Dun et al (2007)
  2. Passive Ranges of Motion of the Hips and Their Relationship with Pitching Biomechanics and Ball Velocity in Professional Baseball Pitchers- Robb et al. (2010)
  3. The Role of Rotational Mobility and Power on Throwing Velocity – Talukdar et al. (2015)


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