Mobility VS Flexibility and Why it MATTERS to BASEBALL players!

With the changing of the seasons outside comes a subsequent change in training seasons, where many summer sports are transitioning into their off-season. As athletes start to file in from a long summer of playing the sport they love, a common theme emerges – these athletes cannot move. They have experienced a significant reduction in their mobility. As I watch them perform their dynamic warm-ups I notice shorter strides, grimacing faces, partial ranges of motion…I could go on and on. It is tough to watch because I know that it is going to take some time to work through these mobility issues before we can get to the phase where we make them better than last season. With off-seasons becoming increasingly shorter, valuable non-competitive training time is being wasted regaining lost mobility instead of being used to make serious physical gains.

But first, what is mobility and why is it so important? Well, this is a complex question that could take countless blog entries to cover. When people hear the word mobility they usually think it is the same as flexibility, but this is not the case. Here is a really simple breakdown of the difference between the two commonly misunderstood terms:

  • Flexibility is the length of the tissue.
  • Mobility, on the other hand, is much more complex; it is the ability of a person to reach a desired position or posture. It is a complex interaction between tissue length, strength, joint stability, the presence of scar tissue, and kinesthetic awareness.


The loss of mobility can be the result of many different factors or a combination factors, such as:

  • Muscle fibers become shortened after times of immobility (sitting at a desk all day) or eccentric stress (deceleration from throwing, running, jumping, etc.).
  • Tissues can become stiff because of instability in surrounding joints; a stiff neck may be the result of instability in the shoulder joint.
  • Mobility can be affected by protective tensions; an athlete may feel as though they have incredibly tight hamstrings, however, this tightness is a protective measure enacted by the body because of an excessive anterior pelvic tilt.
  • And injuries past/present can cause adhesions to tissue, reducing mobility.

Of course there are many other reasons, but these are just a few that are common for athletes.

Many athletes tend to neglect their strength training and mobility work during in-season which is a BIG mistake as the majority of injuries during the season are as a result of loss of mobility as the long gruelling season progresses (I’ve talked about this here and here ). Because of this neglect, loss of mobility becomes a common problem in many athletes, particularly younger athletes. Mobility loss in the early off-season can negatively affect the entirety of an athlete’s off-season training, which can negatively affect their next season, and so on and so on – a potentially compounding problem.

Specifically, here are some areas that baseball players REALLY need to have exceptional mobility if they want to maximize their potential and performance on the diamond:

  • Hip Mobility – many baseball skills require aggressive hip rotation. Sufficient internal and external rotation, adduction, abduction, and extension are key to pitching, hitting and throwing. Proper hip mobility while pitching plays a significant role in avoiding shoulder and elbow injuries by decreasing stress on these joint by up to 20%! Check out the research here
  • Thoracic Mobility – Sufficient mobility in the upper back allows essential separation of the hips and hands during your swing, throws and pitches. When this separation cannot occur due to lack of mobility, ‘energy leaks’ and timing errors are likely to occur. Lack of thoracic mobility can also cause anterior shoulder issues in pitchers, who compensate for lack of range by creating external rotation in the wrong places (ie. excessive external rotation of the shoulder joint).
  • Ankle Mobility – Ankle mobility is important to any rotational movement in baseball. While the hip may initiate rotation, proper movement in the ankle allows the feet to be plated in the ideal position for power transition. Proper ankle mobility is imperative to catchers, as they allow a catcher to comfortably get in a squatting position, allow for more sway to frame pitches, and allow them to get into proper throwing position for base throws.
  • Shoulder Mobility and Stability – The Gleno-humeral joint must be mobile enough to allow for unrestricted movement during the throwing and pitching motion. However, the surrounding structures must be stable enough to protect this joint from excessive movement and dangerous end-ranges often reached by pitchers.

OK, so mobility is important and decreased mobility is not good. So, how do we fix this? How do we go from decreased mobility to increased mobility and subsequently better training, better performance and better resistance to injury? I’ll save that for one of my next entries, so watch for that in the near future.

In the meantime, please feel free to download a copy of our “Player’s Guide to In-Season Strength & Conditioning for Baseball” below.


Courtney Plewes, BScKin, CSCS

SST Mississauga

Athletic Development