Hamstring Strains, More Prevalent Than Tommy John?

As a St. Louis Cardinals fan and performance coach, I took extreme exception to the Cardinals starting the season with 3 players on the DL with hamstring strains (Wainwright, Gregerson, and Gyorko), all before the month of April.  It seemed to me that in a sport like baseball, hamstring strains should be few and far between.  After looking into it, it turns out the Cardinals aren’t the only team that deal with this injury.  In 2016, there were 57 stints on the DL due to hamstring strains at some point and time during the season, totaling almost 7% of all MLB players.  Moreover, the vast majority of them happened before the month of May.   Another study done by the American Journal of Sports Medicine (AJSM) analyzed 50,000 injuries in Major League Baseball from the years 2011 – 2016.  Not only did it demonstrate the same 6.7% injury rate for hamstring strains, but it was almost 2x more likely than the second most common injury (rotator cuff strain), and 3x more likely than UCL injuries.  That’s right, the hamstring is at higher risk than the elbow or shoulder in baseball.   Even more concerning than the rate of injury, was the fact it has been happening at the beginning of the season.  Which leads to the question, why are athletes stepping on the field after a full off season of rest and training and getting hurt?

My first thought, is running mechanics.  Baseball is not known as a sprint dominant sport, but that doesn’t mean the mechanics should be completely neglected.  We see an epidemic of runners who try to “cover as much ground as possible” and have a tendency to reach with their front foot; or runners who don’t have the necessary eccentric hamstring strength to keep their leg from over striding.  Regardless, it causes the same chain reaction.  It starts by the heel striking the ground first, and too far in front of the hips.  This creates a “dragging” motion that relies heavily on the hamstring to “pull” your body forward.  What we would rather see is the knee stay a greater angle of flexion for longer, and the foot strike underneath our hips, with the toe making contact with the ground first.  This creates more of a “push/punch” than a “pull” and recruits the glute, hamstring, and quad at an ideal proportion.   To make things worse, baseball exaggerates this affect when they reach for first base.  When this happens you can see a more dramatic affect of a hard heel strike and extreme knee extension and inefficient use of ground forces that can send a shock through the hamstring.   This constant wear and tear on the hamstring can cause a build up of chronic issues.  At that point all it takes is one bad step to land you on the 10 day disabled list.  

My second, and just as probable, thought is muscular imbalance. There are a couple imbalances that usually play a part in hamstring strains.  The first is an underdeveloped glute max.  The hips (glutes) are the primary hip extensors with the hamstring being a secondary extensor.  Meaning the ideal firing pattern for an athlete going into hip extension should be hips first, then hamstrings.  However, if the hips are underdeveloped, it may result in an anterior pelvic tilt (postural issue) and the hamstring having to act as the primary extensor.  The combination of the anterior tilt and the hamstring having to perform a function it isn’t supposed to leads to a couple problems.  With an anterior tilted pelvis, it puts the hamstring in a continuously lengthened state which cause constant tension on the muscle.  Couple the constant tension with a work load twice the amount it is accustomed to, and you have a series problem.  Most people don't appreciate the massive amount of hip extension that is required of the back leg in order to hit and even more so, pitch.  If athletes can’t get into that position properly due to the aforementioned , it leads to chronic stress that produces injury. 

The second muscular imbalance that is common in hamstring strains, also stems from under active hip and core strength.   There is a small muscle on the inside of the thigh called the adductor magnus.  It attaches at the pelvis and the femur, and is responsible for bringing the femur toward the midline (adduction).  It is also a primary pelvic stabilizer, and is an extensor and lateral rotator of the hip.  Meaning when an athlete goes into hip flexion and/or internal rotation (think front leg mechanics of pitching) or tries to bring the leg away from the midline (think any stride in pitching or hitting), it involves the adductor magnus.  If it is not functioning as it should or is hyper-active due to a lack of balanced strength in surrounding muscles, it makes these movements extremely difficult to get into.  Even further, depending on the severity it, could make these movements even dangerous to get into.  Couple that with coaches that try to force athletes into positions their body isn’t ready to handle, and you have a perfect recipe for a hamstring strain. 

To start fixing this epidemic requires a mix of sprint mechanics, and the correct core and hip work.  However, it cannot be fixed in a week.  In order for this to change it requires a paradigm shift in the way baseball players view training.  They need to begin to understand that training is a year long process.  The days of waiting until January to start training for the season are over.  The faster and more explosive players get, the more imperative it becomes to take part in an individualized, balanced training program to keep them healthy.  Of course we will never be able to eliminate 100% of hamstring strains in baseball, but they certainly are preventable in a large way. 

Author: Jacob Buffa

References

Berra, Lindsey. “Why Are There so Many MLB Hamstring Injuries?” MLB.com, 16 June 2017, www.mlb.com/news/why-are-there-so-many-mlb-hamstring-injuries/c-236844162.

Camp, Christopher L., et al. “Summative Report on Time Out of Play for Major and Minor League Baseball: An Analysis of 49,955 Injuries From 2011 Through 2016.” The American Journal of Sports Medicine, Sept. 2018, p. 036354651876515., doi:10.1177/0363546518765158.

Silvers-Granelli, Holly, et al. “HAMSTRING INJURIES IN MAJOR AND MINOR LEAGUE BASEBALL: ARE THEY PREVENTABLE?” British Journal of Sports Medicine, BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine, 1 Feb. 2017, bjsm.bmj.com/content/51/4/389.1.