It is no secret that elbow injuries have been on the rise in MLB as well as all levels of baseball.  I see far too many adolescent baseball pitchers in my clinic with medial elbow pain.  Often it is related to pathological GIRD and proximal imbalances in the shoulder complex.

Researchers have been studying biomechanics for years.  It has long been a belief that younger pitchers should focus on fastballs and change-ups, while minimizing curveballs. Currently, the prevailing thought and latest evidence seems to suggest that velocity may be the bigger risk factor or determining factor in leading to UCL injuries.


A paper in the August 2016 edition of the American Journal of Sports Medicine from Rush University Medical Center sought to determine factors associated UCLR among MLB pitchers.  The hypothesis was that those pitchers who underwent UCLR would have a higher pre injury pitch velocity.

This retrospective case controlled study looked at data for pitch velocity, type and number for every pitcher and game were gathered from the PitchFx database from April 2, 2007 to April 15, 2015.  Data from 2013 – 2015 was excluded to avoid lead in time bias, as pitches in these seasons may contribute to injuries in pitchers who have not yet undergone UCLR. Pitchers were classified as control, pre injury or postoperative.


  • 1,327 pitchers were included and 309 had undergone UCLR (26.8%) and of those, 145 had pre injury velocity data
  • Peak pitch velocity was 1.2 mph higher (93.3) in pre injury pitchers compared to control pitchers (92.1 mph) – this was considered significant
  • Higher weight (BMI) and age are secondary predictors but only explain 7% of the variance in the UCLR rates
  • No significant difference in overall # of pitches between control and preoperative pitchers
  • Pre injury pitchers threw more breaking pitches but there was no correlation once peak velocity, BMI and age were factored in
  • Likelihood of subsequent UCLR increased sequentially with velocity with 20% of pitchers with peak velocity > 95.7 mph requiring surgery, while only 7.8% of pitchers throwing < 86.9 mph requiring UCLR – a 2.6-fold reduction

Key takeaways

  1. Fatigue is a factor not well understood and one difficult to measure, although recent changes with pitch counts have sought to address this ( and we need more work in this arena
  2. Pitch velocity is the primary risk factor predictive of UCLR in MLB pitchers based on this data.  While it is not a prospective study and relies on public data, it is a large sample size and correlates with prior work published by Bushnell et al.
  3. Pitch velocity along with size and age seem to be potential markers for predisposing pitchers to injury.  This translates to youth baseball as the bigger kids and the hardest throwers are sought after and more likely to pitch too much in the year-round win now environment our kids are going up in today.

What do other papers say? A recent study from the JSES disagrees with the current findings from Chlamers et al. in the AJSM paper in that pitch velocity is not different between injury and control groups, but that the quantity of fastballs is the key factor. Click here to read that abstract

However, a paper from the Orthopaedic Journal of Sports Medicine found that greater velocity (not pitch type) with fastballs, sliders, curveballs, split finger fastballs and change-ups were seen in those pitchers undergoing UCLR.  Click here to read that abstract

In my humble opinion, I feel too much hard throwing at an early age likely contributes to repetitive micotrauma and potentially sets players up for serious elbow injury should they continue to pitch into college and beyond as those in these studies did.  Clearly, we need prospective studies to help validate these findings as well as continued work on looking at other variables that may impact injury risk.

As a physical therapist, coach and father of a hard throwing 6’1″ fourteen year-old left handed pitcher I subscribe to the following:

  • We need to limit pitches and innings per year for those pitchers who throw harder and demonstrate long term potential
  • Young pitchers should learn to throw a change-up at an early age
  • We need to look at how many fastballs hold be thrown at one time
  • Pitchers should refrain from throwing at least 2 months out of the year
  • Youth pitchers should be assessed yearly for asymmetry/imbalances by a medical professional once per year to identify injury risk
  • Players should not pitch and catch in the same game and ideally choose to focus on one or the other as coaches/parents unknowingly abuse young arms by allowing them to do both
  • Arm care is a must for all pitchers and should begin as early as 9 or 10 years old
  • We need to continue to look at the impact of long toss on on throwing mechanics and pitching injuries

I love baseball.  I played for many years and suffered a premature arm injury at age 13 that derailed my pitching.  I have rehabbed MLB pitchers coming back from shoulder and UCL injuries.  Unfortunately, I see too many young people suffering from overuse and fatigue in the climate around me.

My son has potential to pitch and play for some time if he can stay healthy.  My goal is to learn, educate and impact as many parents, players and coaches I can.  Hopefully, we can all continue to gain a better understanding of why we are seeing this epidemic of arm injuries and determine how be a force for positive change in the days, months and years ahead.