Throwing: Decrease Injury by Improving Mechanics

I'm happy to have Kristin Johnson, pro athlete turned physical therapist, share her insights on a growing problem in our sport. Here's the background on Kristin so you know what you're getting is great information!

Kristin Johnson:

2 Time All-American University of Iowa

4 Year Pro Athlete- NPF Akron Racers

9 Year NCAA College Coach

8 Years as a Physical Therapist

Teaching players how to throw is one of the basic skills we instruct at every level of softball. Unfortunately, there is and increasing number of throwing injuries among youth softball and baseball players. These injuries are not only leading to time lost from playing but to an alarming increase in the number of shoulder and elbow surgeries performed on young throwing athletes. Among baseball players there has been a seven-to-tenfold increase in Tommy John surgeries to the elbow since the year 2000. Personally, over the course of my collegiate coaching career I saw an increase in the number of incoming softball players who had undergone shoulder surgeries as teenagers, mostly arthroscopic debridement. This is a red flag. When the number one predictor of injury is previous injury I am hesitant to recruit a player who has known shoulder or elbow issues (and likely poor throwing mechanics as the cause). Highlighted below are some basic coaching tips you can use to improve your players’ throwing mechanics which will maximize their velocity and accuracy as well as decrease their chance for injury.

So what makes for good throwing mechanics? What puts the least amount of stress on the shoulder and the elbow? What optimizes the efficiency of energy transfer through the kinetic chain, from the legs up, to generate speed and accuracy on the throw? How much is too much?

Pitch Counts

Dr. James Andrews is one of the leading experts on throwing injuries and he has published the commonly adopted pitch count recommendation for youth baseball leagues. He has also published pitch count recommendations for softball although these numbers are not as well researched as the baseball numbers. While these guidelines are based more on expert opinion than hard data they at least offer some general guidelines:

Recommended Softball Pitch Count Guidelines:

Girls < 12 yrs old – only 2 days of consecutive pitching

Girls > 12 yrs old – only 3 days of consecutive pitching

Differences between Baseball and Softball Injuries

Most of the published research on throwing mechanics and throwing injuries are on baseball players. Thankfully the throwing mechanic is generally the same for both sports so we can extrapolate some of the findings from baseball to softball. Before going over this common throwing mechanic a few of the differences include:

  • Biceps muscle activity is twice as high during the softball windmill pitching motion as that during baseball pitching. Not surprisingly there is an increase incidence of anterior shoulder pain and biceps tendonitis/tendonosis in softball pitchers.

  • Baseball pitchers elbow injury rate is higher than softball pitchers or position players. In a study of high school aged baseball and softball athletes, 50.2% of elbow injuries occurred while pitching in baseball but only 11% occurred while pitching in softball. Interestingly, if all injuries occurring during pitching were removed than the difference between elbow injury rate for baseball and softball would no longer be significant.

  • Softball players have a greater propensity for injury of the lower extremities in all phases of the sport (not just throwing).

  • More softball injuries occur as base runner or batter than pitcher.

The Kinetic Chain

In a study by baseball researcher Glenn Fleisig, he found that when comparing youth league, high school, college, and pro pitchers the successful pitchers at all levels had virtually the same mechanics. Harmful force and torque placed on the joints of the arm weren’t just proportional to body weight (i.e. how big the pitcher was) but the force and torque were more proportional to good or bad mechanics.

In other work, Kibler and Chandler calculated that a 20% decrease in kinetic energy delivered from the hip and trunk to the arm requires a 34% increase in the rotational velocity of the shoulder to impart the same amount of force to the hand. In layman terms: decreased leg drive can lead to compensation with the arm.

Coaching Tips

There are 5 (to 6) phases of the overhand throw that include: wind-up, stride/cocking (early and late), acceleration, deceleration, follow-through. This can be a complex motion but you don’t need to be a biomechanical expert to give helpful coaching tips. Below are a few coaching pointers to help your athletes achieve some of the critical phases of throwing:

“Hips lead the throw” Once you start your body moving toward the target your hips should be ahead of your upper body. This ensures good leg drive and energy transfer from the ground up. Without good leg drive we try to compensate with the arm. I love the picture of the softball catcher here because this principle can even be achieved with a throw from the knees.

“Keep your hand on top of the ball” During the wind-up when the hands first separate (i.e. ball out of glove) the throwing hand should be on top of the ball, pointing the ball toward the ground. Too often young kids, girls especially, point the ball up or back in order to try to grip the ball. Unfortunately, this can lead to early shoulder external rotation and horizontal ABD causing strain on the anterior shoulder and its structures. The hand should still be on top of the ball at foot contact (when stride leg first hits the ground).

“Shoulder and elbow up”

Once your lead foot contacts the ground the throwing elbow should be up near its highest point and the shoulder should be at 90 degrees ABD (i.e. can draw a 90 degree angle from torso through upper arm). If the elbow is low this can again lead to anterior shoulder as well as medial elbow strain. The good news is that Fleisig found that this principle can be achieved regardless of arm slot. So whether the trunk is upright as with an overhand throw or leaning to the side with three-quarter or sidearm throws it’s still possible to keep the optimal 90 degree shoulder angle and thereby protect the arm.

“Keep the lead shoulder and foot

toward your target”

Keeping your shoulders and hips closed will facilitate the entire body moving in one direction. The front foot is planted slightly inward or to 3B side (for a right-handed pitcher). If the lead shoulder or hips open too early the body’s forces are pulling in different directions and the arm is left in a vulnerable position as it whips through the throwing motion. Sometimes we teach our players to point their glove at the target but this may actually lead them to open their shoulder up too early.

“Keep a long follow through”

After releasing the ball let the arm finish long, over and across the body, and down toward the ground with the trunk leaning forward. Pulling the arm up short doesn’t allow enough time for the rotator cuff to keep the arm in a neutral position. This is a critical phase because as you throw your arm is trying to come out of the shoulder socket and your arm muscles are counteracting this force which can be upwards of 1.5x your body weight.

Do’s & Don’ts

In light of what I’ve learned as a physical therapist I’ve had to rethink some of the throwing drills I’ve commonly used with my players. For example, in college we started every practice throwing dart throws from our knees then progressing to half-kneel in which we waved “bye-bye” with the ball before throwing toward our partner. While these drills were well intentioned I would argue that they are not the best drills. Wrist flicks and dart throws are basically pointless as this is the end of the kinetic chain which has far more important phases (highlighted above) that lead to throwing accuracy, velocity, and preservation of the arm. And waving “bye-bye” with the ball can lead to early shoulder external rotation and horizontal ABD which causes increased strain on the anterior shoulder.


  • wave “bye-bye”

  • point the glove or the toe directly at the target (opens shoulders/hips too early)

  • follow through with a whipping, short arm action

  • throw with fatigue (youth baseball pitchers who threw with fatigue had a 36 to 1 chance to injure their shoulder or elbow)

  • waste time on wrist flick drills


  • drive hips toward target

  • keep hand on top of ball/point ball toward ground when hands separate and still some at foot contact

  • plant foot slightly closed

  • long slow follow-through with arm down toward ground and trunk forward

  • allow your athletes at least 3 months (4 may be better) of no throwing

  • encourage your athletes to play other sports or to have several months off of a single sport. Specializing in a single sport by playing it more than 8 months per year has been correlated with serious overuse injuries, anterior knee pain, and hip injuries.

  • train your adolescent or older athletes in core and shoulder stability exercises which have been shown to increase velocity up to 3 mph

A few of the resources referenced above:

Davis, J.T. The Effect of Pitching Biomechanics on the Upper Extremity in Youth and Adolescent Baseball Pitchers. Am J Sports Med 2009 37: 1484


[Epidemiological Comparison of Elbow Injuries among US HS Baseball and Softball Players, 2005 – 2015, Pytiak A Sports Health March/April 2018 Vol 10

#throwingmechanics #baseball #softball #throwinginjuries #softballtraining