Welcome to Driveline’s pitching research page

Here is where we will start our review of studies and their relation to baseball.

You can see a longer list of the studies we have collected here.

If have any interesting studies to share you can send them to support@drivelinebaseball.com and we may review and post them with attribution.

How to use this page:

We do our best to experiment and validate much of the research that we read. We will link to the abstract of each paper to encourage you to do your own investigation/observation/experimentation. These studies should be taken as a jumping point for your own research. Each is simply a piece of the puzzle not law of the land.

“If you don’t experimentally validate research you picked up out of a textbook or published paper, that’s not science. That’s faith.”

New Studies

Correlation of Shoulder and Elbow Kinetics with Ball Velocity in Collegiate Baseball Pitchers (Open Access)

With a group of 67 NCAA D1 pitchers, the researchers examined the correlations between elbow-valgus torque, shoulder-distraction force and shoulder external-rotation torque and ball velocity. The hypothesis was that there would be a moderate positive correlation between those factors and ball velocity. Meaning the harder that an athlete throws the more force and torque they experience on their arm.

A weak positive correlation was found between ball velocity and shoulder-distraction force (r=0.257) but no significant correlations were observed between ball velocity and elbow-valgus torque or ball velocity and shoulder external-rotation torque.

This is an interesting finding considering other research pointing toward increase in velocity being and increase in stress on the arm. What it does suggest is that changes in forces of the arm are more individualized than previously believed.

The researchers also bring up an interesting point that having a sample size of D1 baseball players may bring a type of ‘survival bias’ into play. The relationship very well may change when looking at a different sample of pitchers.

Relationships between ball velocity and throwing mechanics in Collegiate Baseball Pitchers

This study wanted to investigate between pitching mechanics and how they related to throwing velocity. 54 pitchers were included (34 right handed pitchers and 20 left handed pitchers) from NCAA and  NAIA schools. 26 body landmarks were tracked and the researchers looked only at the three fastest fastballs thrown for strikes.

The researchers found 10 variables that ended up accounting for 68% of the variance in ball velocity. They were: body weight, time from stride foot contact (SFC) to max external rotation (MER), knee flexion at SFC, elbow angle at SFC, length of time the head stayed behind the hips, maximum shoulder external rotation, maximum upper trunk rotation speed, peak elbow extension angular velocity, knee flexion at ball release and forward trunk tilt at ball release.

The average ball velocity of the 54 pitchers was 79 MPH. It would be interesting to see if these findings stood up with pitchers throwing at higher velocities (90 MPH). As pitchers get to elite velocities (85+) there is a good chance that the importance of different variables would change.

It’s also interesting that those 10 variables only accounted for 68% of variance of velocity was accounted for. Leaving an open question for what measurables could make up the other 32%.

Effects of Acute Static Stretching of the Throwing Shoulder on Pitching Performance of National Collegiate Athletic Association Division III Baseball Players

The researchers had 6 pitchers and 6 position players go through 2 separate throwing protocols, one control group and one group that went through a 6 static stretch routine.The literature on static stretching before exercise has been mixed, usually showing either a decrease or no change in performance.

In the experiment each athlete held the 6 stretches for 30 seconds. The stretches included a horizontal adduction, horizontal abduction, external rotation, internal rotation, flexion and extension stretch.

The 6 stretches did not have any significant effect of pitching performance, velocity or accuracy. This is in line with previous research by Young et al. which proposed that participants with well-developed movements patterns wouldn’t be significantly affected by acute static stretching. This would also somewhat explain why position players experience less accuracy than the pitchers in the study. The pitchers obviously have more experience throwing off a mound.

This study only recorded 10 pitches and there was a rest period of 5-10 minutes before each athlete pitched. This rest may have negated the effects of the static stretching. Results may be different with different time between the stretching and throwing or having the participants throw more pitches.

  • This study was brought to our attention by Jarad Vollkommer

Contributing Factors for Increased Bat Swing Velocity

This is an excellent review of forty abstracts, papers and books of what training methods have been investigated for improving baseball and softball swing velocity.

Research on improving bat speed, using weighted bats in the on-deck circle and using under and overweight bats is included. The review also investigated whether significant relationships could be found between different strength and power metrics or resistance training and bat swing velocity.

Specific training with under and overweight bats was found to improve bat velocity, bat velocity will also increase with resistance training programs. Players with the greatest bat swing and batted-ball velocities had more lean body mass, greater strength and power.
There was a mix of conclusions in the literature of the importance of grip strength but the researchers concluded that additional forearm and grip exercises do not contribute to increase bat velocity.

The Marc Pro Device Improves Muscle Performance and Recovery from Concentric and Eccentric Exercise Induced Muscle Fatigue in Humans: A Pilot Study (Open Access)

This paper consists of reviews of 2 studies. The first wanted to examine the effects of the Marc Pro on delayed onset muscle soreness (DOMS) of 14 participants. The goal was to compare perception of soreness, muscular endurance, and DOMS between legs.

In the first study researchers had each participant perform leg extensions and then use the Marc Pro on only one of their legs for one hour. After the workout the perception of soreness assessment showed less muscle soreness and discomfort on the leg that used the Marc Pro. Participants were able to complete more repetitions on average with the leg that received treatment from the Marc Pro than the leg with no stimulus.

The second study had 13 participants hike up and down Bulls Hills reservation of greater Boston until they achieved quadriceps muscular fatigue. Subjective soreness assessments showed significantly less discomfort in the leg that received stimulation via the Marc Pro versus the control leg. The researchers also split the exercise groups up into high and low response groups which found both groups experienced a decrease in DOMS and increase in muscular endurance.

The studeis suggests that the Marc Pro may significantly reduce DOMS caused by eccentric exercise. Though these findings were on middle age participants.  It would be encouraging to see a similar study carried out within a younger consistently trained population.

Effects of Electrical Stimulation Using the Marc Pro Device during the Recovery Period on Calf Muscle Strength and Fatigue in Adult Fitness Participants (Open Access)

This study wanted to compare strength and recovery in adults who followed an exercise program over a period of 10 weeks. Two studies are included in this review. Both studies split the participants in half with one group using the Marc Pro after exercise on both calf muscles while the other didn’t use the Marc Pro.

Calf muscle strength was measured at the beginning and after 10 weeks by a 3 repetition maximum load. Calf muscle fatigue was assessed on a subjective 9-point rating scale.

Percent body fat, fat weight and lean weight were also measured and there was no significant difference between Marc Pro and no Marc Pro groups. But there were significant changes in calf muscle strength and fatigue.

Both studies showed increase in strength with the Marc Pro group experiencing a significantly greater increase in strength over the no Marc Pro group. This suggests that using the Marc Pro after resistance training may be effective for increasing muscle strength.

One study showed a significant difference of experienced calf fatigue between the Marc Pro and no Marc Pro groups. With the group using the Marc Pro showing the larger difference. The second study showed no statistically significant difference in calf muscle fatigue.

The groups that used the Marc Pro also experienced a greater decrease in feelings of calf fatigue when compared to the no Marc Pro group.

The researchers propose that “the enhanced muscle recovery associated with MPD (Marc Pro Device) electrical stimulation may be due to increased micro circulation, muscle loading, and angiogenesis” Better muscle recovery would of course provide a greater opportunity to increase work capacity which may promote greater strength gains.

Relationship Between grip, pinch strength and Anthropometric Variables, types of pitch throwing among Japanese High School Baseball Pitchers (Open Access)

133 high school pitchers participated in the study where grip strength and pinch grip strength were measured using a digital dynamometer. The researchers hypothesized that frequency of pitch types in pitchers would be influenced by grip and pinch strength measurements. The theory being that pitchers who are stronger in certain grip positions would then have a higher frequency of certain offspeed pitches thrown.

Grip Strength, tip, and palmar pinch strength and muscle mass of upper extremity of the pitchers dominant side were statistically greater than those of the non-dominant side. But key pinch strength of the non-dominant side was greater than dominant side.

The researchers found no significant correlation between throwing ratio of difference pitches and grip strength of tip, key or palmar pinch.
Additional research should be pursued in older populations to see if the results change or if there are any additional findings.

Shoulder Rotator Muscle Dynamometry Characteristics: Side Asymmetry and Correlations with Ball-Throwing Speed in Adolescent Handball Players (Open Access)

This study wanted to compare shoulder external/internal rotator muscle peak and average measurements and then determine the correlations between those measurements and throwing velocity.

The researchers found positive correlations between certain isokinetic measurements and ball speed. The correlation between external rotator muscle peak torques and ball speed was (r=0.69) higher than internal rotator muscle peak torque and ball speed (r=0.61) at the fastest velocity measured(240 degrees/second). This suggests that external rotational force may be more important to higher velocity that internal rotation force. More research is need, especially with baseball players, to examine the relationship between external and internal rotational force and velocity.

There was no significant asymmetry in shoulder external/internal rotator muscle peak torques and average power values at the measured speeds.

Weighted Ball Training

The exact mechanism on how weighted baseballs increase velocity is unknown. However, Soviet-science research on over/underweight implements provides a great hypothesis: With underweight training the arm will move at higher speeds with less muscle force generated. Overload training causes the arm to move at a slower speed but with greater muscle force. Over- and under-weighted-ball training can be seen as a form of “speed-strength” or “power” training for the arm. Power training by definition conditions the neuromuscular system to develop the greatest amount of force in the least amount of time.

Expand for Vocab
Neuromuscular system – combination of how the nervous system and muscles work together in movement

Effect of Baseball Weighted Implement Training: a Brief Review

Authors: DeRenne, Coop; Szymanski, David

This is the study to start with if you are interested in learning about weighted baseballs and weighted-bat training. Between reading the review and looking up the references, we found a solid research base in the support of weighted-implement training in baseball. This is a great complement to the decades of research in support of weighted-implement training in Track and Field.

  • This paper looked at 11 weighted-baseball studies and suggests that weighted-ball training not only increases velocity but also may be used for injury prevention.
  • It also looked into the use of weighted bats and their use in warm-ups and improving swing velocity.

Effects of Throwing Overweight and Underweight Baseballs on Throwing Velocity and Accuracy

Authors: Escamillia, RF; Speer, KP; Flesig, GS; Barrentine, SW; Andrews, JR

This study reviewed a number of weighted-ball studies and how different training protocols affected velocity and accuracy.

  • Four out of five studies found that training or warming-up with an overweight baseball produced an increase in the velocity of the baseball.
  • Warming-up with heavier baseballs was not found to increase velocity for that training day.
  • More research is needed on the effects of warm-up with baseballs of different weights.
  • No study found that accuracy was improved by using heavier baseballs in training.
  • Ten of the eleven studies showed an increase in velocity using both over- and underweight balls.
  • No injuries were reported, but more research should be done on arm stress with baseballs, specifically ones of varying weight.
  • More research should be done on the kinetic and kinematic difference between throwing a baseball versus and over- and underweight balls.

This paper does an excellent job of breaking down the variety of training protocols that have been experimented with using weighted baseballs. The relationship between accuracy and weighted baseballs is something we are currently investigating with different training protocols.

Expand for Vocab
Kinetic – using physics to study motion and its causes, namely forces occurring in the pitching motion in this instance

Kinematic – branch of mechanics that describes the motion of points using math and geometry to figure the velocity or acceleration of various points of the body, in this case of a pitcher

Effects of Under- and Overweighted implement training on pitching velocity

Authors: DeRenne, Coop; Buxton, Barton P; Hetzler, Ronald K; Ho, Kwok W

Weighted-baseball training using over- and underweight baseballs can be beneficial in increasing velocity when implemented under various training schedules. Both groups of weighted-ball trainees showed statistically significant velocity gains over the control group. No participant reported shoulder pain or injury during the 10-week training period.

No other weight training program was used during the study

Expand for Vocab
Statistically significant – the likelihood that a relationship is caused by something other than mere random chance.

Comparison of Kinematics Between Overarm Throwing with 20% Underweight, Regular, and 20% Overweight Balls

Authors: Van den Tillaar, Roland; Ettema, Gertjan

This study examined different joint movements during a throw in experienced female handball players. Maximal angles, angles at ball release, and maximal angular velocities of the joint and their timings were analyzed during the throw.

Both maximal internal-rotation velocity of the shoulder and maximal elbow-extension velocity significantly changed when throwing the weighted balls. The timing of the maximal elbow-extension velocity changed significantly as well as the timing of the maximal external-rotation angle of the shoulder. Maximal external rotation of the shoulder occurred closer to ball release when throwing the light ball when specifically compared to the other balls.

Previous studies by van den Tillaar and Ettema (2004, 2007) showed that the internal rotation of the shoulder and elbow extension were the main contributors for the maximal ball-velocity at release.

This supports the notion that weighted baseballs improve velocity by training internal rotation and elbow extension. Motor-learning research shows training small variations of a movement results in faster learning rather than repeating the same skill.

Effect of Different Training Programs on the Velocity of Overarm Throwing: A Brief Review

Authors: van den Tillaar, Roland 

This is a large review of how different training studies affect velocity. The studies were divided into 4 categories for review:

(a)  specific resistance training with an overload of velocity.

(b) specific resistance training with an overload of force.

(c) specific resistance training with a combination of overload of force and velocity.

(d) general resistance training according to the overload of force.

If you are looking to read further on results of using weighted balls in controlled settings, this study is a great resource. This review looks critically at how these studies were run with control groups, group sizes, training age, number of throws, etc.

The data presented indicates that training with underweight balls alone or in combination with overweight training enhances velocity. Training studies with overweight balls gave conflicting results.

A Force-Velocity Relationship and Coordination Patterns in Overarm Throwing

Authors: van Den Tillaar, Roland; Ettema, Gertjan

This study examined the force-velocity relationship with handball players using ball weights varying from 0.2 to 0.8 kg. An examination of the data found a significant, negative relationship between force and maximal-ball velocity, as well as between ball weight and maximal-ball velocity. This means that the heavier the ball weight, the lower velocities that were seen. It was also seen that the heavier the ball weight, the more time it took before release. Angular velocities of the arm joints also decreased with the increasing ball weight.

It was also found that there were no changes in the relative timing of the different joints, suggesting that the overall coordination pattern of throwing is independent of ball weight.

Internal rotation of the shoulder (63%) and elbow extension (32%) were found to be the main contributors to total ball velocity at release. Maximal internal-rotation of the shoulder occurred at ball release and maximal extension of the elbow occurred on average 0.01 seconds before ball release. Elbow extension preceded the onset of the internal shoulder rotation. These joints most likely obtain these high speeds by making use of slower movements in other joints in a kinetic chain of movement.

Baseball Reviews

Ball Speed and Release Consistency Predict Pitching Success in Major League Baseball

Authors: Whiteside, David; Martini, Douglas N.; Zernicke, Ronald F.; Goulet, Grant C.

This study aimed to quantify which metrics could best predict pitching success. The study included 190 pitchers. They took one hundred fastballs, changeups, curveballs and sliders to analyze for each pitcher for a total of 400 pitches.

The regression model used found that pitch speed, release-location consistency, variation in pitch speed, and horizontal-release location were significant predictors of Fielding Independent Pitching (FIP). Yet those factors only explain 24% of the variance of FIP.

Pitch speed was a significant predictor that explained 10.4% of the variance of FIP. Based on the regression model, a 1% increase in pitch speed produced a 2.3% improvement in FIP. This suggests that, of the metrics analyzed, increasing pitch speed may be the most beneficial factor in improving performance. Of course, it is also believed that increased pitch speed also comes with greater loads on the arm.

Release-location variability of all four pitches was significantly correlated to FIP. Suggesting that throwing all pitches from the same release point, paired with an increasing pitch speed, should be main focuses of training.

Variation in pitch speed, the speed difference between a pitcher’s fastballs and offspeed throws, was another significant predictor of FIP. Interestingly, pitch-speed variation did not significantly correlate with FIP in any of the individual pitch types, which suggests that the pitch-speed difference should be examined over a pitcher’s whole repertoire, not individually.

A more pronounced horizontal-release location was also a predictor of FIP. The reasoning for this is unclear, but in theory this would suggest that lower-arm slots, like sidearm pitchers, have lower FIPs. Another reason could be that sidearm pitchers are more rare, but both are purely speculative.


Should We Limit Innings Pitched After Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers?

Authors: Erickson, Brandon J; Cvetanovich, Gregory L.; Bach, Bernard R; Bush-Joseph, Charles A; Verma, Nikhil N; Romeo, Anthony A.

This study examined whether putting pitchers who were coming back from Tommy John surgery on pitch counts reduced their chance of having a revision UCL surgery.

The study included 154 pitchers who underwent UCL surgery from the year 1974-2015 , and 135 did not require revision UCL surgery. When comparing the two groups of pitchers, no significant difference was found between the number of innings pitched in the season after UCL surgery, number of pitches thrown, number of innings pitched in the pitcher’s career post op, and number of pitches thrown in the pitcher’s career post op. There was also no difference in revision rate between pitchers who pitched more or less than 180 innings in their first full season back from injury.

This study suggests that restricting innings and pitches post surgery doesn’t guarantee that a pitcher will stay healthy. However, this doesn’t mean that pitch counts wouldn’t be successful in keeping pitchers healthy preemptively. A study examining a preemptive reduction in workload and pitchers health would be an interesting compliment.

MLB pitchers are much more physically mature that youth and high school athletes. Studies should also examine the effectiveness of pitch counts on younger athletes over many years of playing.

Is Tommy John Surgery Performed More Frequently in Major League Baseball Pitchers From Warm Weather Areas? (Open Access)

Authors: Erickson, Brandon J., Harris, Joshua D., Tetreault, Matthew, Bush-Joseph, Charles; Cohen, Mark; Romeo, Anthony

This study wanted to see if being raised in a warm-weather climate had an effect on Tommy John risk for MLB pitchers. Warm- and cold-weather climates were divided using the 33rd parallel, with every state that the parallel goes through being a “warm-weather” state. Every state above the 33rd parallel was considered a “cold-weather” state.

Using this criteria, the researchers found:

  • In MLB history 64.5% of all players were from cold-weather areas.
  • 35.5% were from warm-weather areas.

Of a total of 247 MLB pitchers that had Tommy John surgery as of June 1, 2014

  • 56.3% pitched in high school in warm weather areas
  • 43.7% pitched in high school in cold weather areas

This data shows that playing high school in a warm-weather climate is linked to pitchers having UCL reconstruction more frequently than pitchers who played in a cold-weather climate. This is most likely do to pitching for longer periods of time and throwing more innings in a calendar year.


Anthrompometric and Performance Comparisons in Professional Baseball Players

Authors: Hoffman, Jay R; Vazquez, Jose; Pichardo, Napoleon; Tenebaum, Gershon

This study assessed 343 professional baseball players for height, weight, body composition, grip strength, vertical jump power, 10-yd sprint speed, and agility. The playing levels ranged from MLB to Rookie ball, and all testing was done at the beginning of spring training.

Rookie- and A-ball players were significantly leaner and had lower lean-body mass than AA, AAA, or MLB players. Grip strength was higher in MLB and AAA than in Rookie and A ball. AAA reported the highest grip strength. Significant correlations were seen between grip strength and home runs, total bases and slugging percentage.

MLB players were faster than all other levels (.03-.07 secs faster). MLB players had higher vertical-jump measures than AA, A, and Rookie ball (.3-1.1 inches higher).

No significant differences were found in vertical-jump height, but MLB players had significantly greater peak and mean jump power than players in lower levels.

No significant differences were found in vertical jump height but MLB players had significantly greater peak and mean jump power than players in lower levels.

Regression analysis revealed that performance measures accounted for 25-31% of the variance in baseball-specific power production. Anthropometric measures failed to add any additional explanation to the variance.

Effect of age on Anthropometric and Physical Performance Measures in Professional Baseball Players

Authors: Manquine, GT; Hoffman, JR; Fragala, MS; Vazquez, J; Krause, MC; Gillett, J; Pichardo, N

This study broke professional baseball players into 7 cohorts based on age (from under 20-35+) to compare how different physical and performance metrics changed between age brackets. Lower-body jump power, speed, agility, grip strength and body composition were all examined.

Players from age group 20-22 were significantly lighter than players in age group 23-31. In general, pitchers were heavier than position players. A significant correlation was seen between age and weight, but age only explains about 7% of the variability of body mass changes. Lean body mass only had a significant increase in players over 23, with peak LBM coming in ages 29-31.

No significant differences were found between age groups in the 10-yd sprint times. An 18% difference in grip strength was found between the lowest strength group (under 20) and peak strength (age 29-31).

Vertical jump was consistent between players under 20-28 and became significantly lower in athletes playing in their 30s. This primarily came from a reduction in vertical jump in pitchers as position players maintained their verticals. This being said, there has been little evidence of a strong relationship between vertical-power and vertical-jump measures and pitching performance. It’s more likely that pitchers, as they age, rely more on pitching specific skills than any one performance measure.

The researchers do note an important caution at the end of the research paper. This was a cross-sectional study, not a longitudinal study examining the same players over the course of their careers. Results in this case will be influenced by genetics and skill.

Relationship between Shoulder and Elbow Isokinetic Peak Torque, Torque Acceleration Energy, Average Power, and Total Work and Throwing Velocity in Intercollegiate Pitchers (Open Access)

Authors: Pawlowski, David; Perrin, David H

These researchers wanted to see if there was a relationship between strength and power of certain muscles and velocity. Data collection occurred using isokinetic testing using a Cybex II isokinetic dynamometer.

Shoulder flexion/extension, shoulder internal/external rotation, elbow flexion and extension were tested at speeds of 60 and 240 degrees/second. Ten pitchers were tested for peak torque (PT), torque acceleration energy (TAE), average power (AP) and total work (TW).

For shoulder internal rotation at 240 deg/sec, significant correlations were found between throwing velocity and PT, TAE, AP, and TW. Significant correlations were also found between throwing velocity and shoulder external rotation (240 deg/sec), PT, AP, and TW. Interestingly enough, no significant correlations were found between throwing velocity and shoulder internal/external rotator muscle groups at 60 deg/sec.

The results of the study do not establish a direct cause-and-effect relationship. But they do suggest specificity of exercise for training shoulder internal- and external-rotator muscle groups. The study also points out that the speed that throwing a ball occurs at approximately 9,000 deg/sec, so isokinetic measurements at faster speeds (240 deg/sec) may better represent testing that relates to throwing velocity.

Baseball Athletic Test: A Baseball-Specific Test Battery

Authors: Spaniol, Frank J.

This researcher examined current baseball literature to create a baseball-specific testing protocol by referencing body composition, flexibility, muscular strength, leg power, rotational power, agility, running speed, throwing velocity and bat speed studies.

This study is a great collection of data that creates an easy reference point for any coach who wants to compare measures of players of different ages and abilities by specifically comparing high school, NAIA, and D1 athletes.


Elbow Injuries and Tommy John

Performance, Return to Competition and Reinjury after Tommy John Surgery in Major League Pitchers

Authors: Makhni, EC; Lee, RW; Morrow, ZS; Gualtieri, AP; Gorroochurn, P; Ahmad, CS

Tommy John is absolutely not a simple surgery with a guaranteed success rate. We often only hear of the pitchers who exceed expectations and come back quicker or of the ones that can still play at a high level. We fail to realize the number of players who do not return or only return for a short period of time.

Statistics that stood out:

  • 147 pitchers were considered active before undergoing TJ (played >1 MLB game from 1999–2011).
  • 29 pitchers (20%) failed to return to MLB competition.
  • 19 pitchers (13%) returned but pitched less than 10 innings.
  • 99 pitchers (67%) were left who returned to throw 10+ innings in MLB.
  • More than 50% of players returned to the DL because of injuries to their throwing arms after returning from surgery.

This study excluded 10 players who had multiple surgeries (21 combined)

Rate of Return to Pitching and Performance after Tommy John Surgery in Major League Baseball Pitchers

Authors: Erickson, BJ; Gupta, AK; Harris, JD; Bush-Joseph, C; Bach, BR; Abrams, GD; San Juan, AM; Cole, BJ; Romeo, AA

For Tommy John studies it is required that you investigate the numbers and do not blindly accept the conclusion. For example, this study concluded “…reconstruction of the UCL allows for a predictable and successful return to professional baseball.” It is simply not that straightforward.

Statistics that stood out:

  • 179 active MLB pitchers were considered active from 2010–2013 (7 pitchers were excluded for revision UCL tears, and 37 were excluded because they were <18 months post op).
  • 148 (83%) returned to pitch at minimum 1 inning in MLB.
  • 26 (14.2%) returned only to the minor leagues.
  • 5 (2.8%) never pitched again.
  • At the start of the 2013-2014 season (last year of the study), 56 (32%) pitchers were still active in the MLB.

“A player was deemed to have returned to pitching if he pitched in any MLB game after surgery.”

Possibly the most important quote from the study: “To date, there (is) no data to support or even consider prophylactic (preventative) UCL reconstruction to improve throwing velocity or prevent injuries in the future.”

Authors: Jiang, Jimmy; Leland, J

This study looked at MLB pitchers between the 2008-2010 MLB seasons and analysed pitcher velocity pre and post surgery.

  • 41 pitchers in total had UCL reconstruction between those years
    • 3 were excluded for revision UCL surgery
    • 1 retired, 7 never returned to the majors
    • 1 fractured a forearm and 1 lacked insufficient prestudy data
    • This leaves 28 pitchers available for statistical analysis
    • No pitcher returned with a high average velocity compared to before surgery

Velocity of fastball and changeup(s) thrown by pitchers who return to MLB after UCL reconstruction decreased by a small, but statistically significant, values from preinjury to postinjury years. There was not a significant difference in the mean velocity of those pitches when compared to a control group of pitchers without a known UCL injury.

Although the velocity difference was small, there is a much smaller chance of a team signing a pitcher who was 90-92 then had Tommy John and came back 88-90. More can and should be done in training these athletes when coming back from surgery.

Outcomes in revision Tommy John surgery in Major League Baseball pitchers

Authors: Liu, Joseph; Garcia, Grant; Conte, Stan; El Attrache, Neal; Altchek, David; Dines, Joshua

  • Since 1999, 235 pitchers underwent Tommy John, 31 (13.2%) underwent revision surgery
  • Of those 31 pitchers, 26 were available for return to play analysis, 17 (65.4%) returned to pitch at least 1 MLB game
  • only 11 (42.3%) returned to established play (pitch in 10+ games)
  • the number of UCL revision reconstructions per year performed on MLB pitchers from 1999 to 2014 significantly increased to one-third of all Tommy John surgeries in 2014

This study strongly suggests that the risk of having revision surgery after Tommy John surgery may be increasing. This is a trend that will need to be watched closely. More attention should be focused on the rehabilitation and training of athletes coming back from surgery.

The Effects of Medial Ulnar Collateral Ligament Reconstruction on Major League Pitching Performance

Note: the Ulnar Collateral ligament (UCL) can also be referred to as the Medial Ulnar Collateral Ligament.

Authors: Keller, Robert; Steffes, Matthews; Zhuo, David; Bey, Michael; Moutzouros, Vasilios

  • 168 Pitchers were included in the study between the years 1982-2010
  • Those pitchers pitched in at least 1 major league game before undergoing MUCL surgery
  • 87% of pitchers returned to pitch (1 inning) in MLB
  • There was a statistically significant decline in pitching performance that improves in the 2nd and 3rd year but not fully to previous levels.
  • Pitching performance declined the year before surgery

The last bullet is interested and suggests the fact that Tommy John may be multi-causal. Pitchers may attempt to try and pitch through some sort of injury that over time may get worse or lead to a different injury such as a UCL tear.

A Systematic Review of Ulnar Collateral Ligament Reconstruction Techniques

Authors: Watson, Jonathon; McQueen, Peter; Hutchinson, Mark

Because of the increase in Tommy John surgery this study wanted to compare the success rates of different techniques of Tommy John. Comparing these techniques would allow patients and surgeons to see if one technique had fewer complications or an improved return-to-play rate.

  • Total of 21 studies (7 biomechanical and 14 clinical) met the inclusion criteria.
  • This included 1368 patients that underwent surgery
    • 239 (17.5%) were high school or recreational athletes
    • 585 (42.8%) were college athletes
    • 481 (35.2%) were professional athletes
    • 63 (4.5%) were not classified into the previously mentioned groups.
  • 18.6% (255/1368) had complications with the surgery

In comparing the Jobe technique, modified Jobe technique and docking technique the docking technique resulted in a significantly higher rate of return to play and a lower complication rate. It’s important to note that some techniques may be used because each surgery is different and may have complications so that one technique may be eliminated. The techniques of the surgery are still evolving which should continue resulting in high rates of return and less complications across the board.

Lastly most UCL reviews look at just professional athletes were this study included high school, recreational and college athletes who are going to have very different resources available for rehab than professional athletes.

Medial Collateral Ligament Reconstruction in the Baseball Pitcher’s Elbow

Authors:  Erne, HC; Zouzias, IC; Rosewasser, MP 

The Medial Collateral Ligament (MCL) is composed of: the anterior bundle, the posterior bundle, and the oblique bundle (or transverse ligament). It is the anterior bundle (located on the inside of the elbow, closest to the body) that is most vulnerable to valgus stress with the elbow extended. The posterior band is more vulnerable with the elbow flexed.

The highest amount of force on the elbow is seen when pitchers transition from the cocking to acceleration phase of the throwing motion, at maximal external rotation. It is repetitive valgus stress that make pitchers prone to elbow injuries.

When an injury has occurred there is often a decrease in velocity and command along with pain. But not all elbow pain is an MCL injury. If an athlete is experiencing pain they should see a doctor or physical therapist.

Pitch Velocity Is a Predictor of Medial Elbow Distraction Forces in the Uninjured High School-Aged Baseball Pitcher (Open Access)

Authors: Hurd, Wendy J; Jazayeri, Reza; Mohr, Karen; Limpisvasti, Orr; El Attrache, Neal S; Kaufman, Kenton R.

It’s believed that the cause of medial elbow injuries is excessive ligament tension during the late arm cocking phase. There is also a relationship between pitch velocity and elbow injuries.

This study wanted to look specifically at the relationship between pitch velocity and high medial elbow adduction moments.

The researchers found that the pitchers who had the greatest pitch velocity also have greater medial elbow adduction moments. The joint moments found were biomechanically related to pitch velocity. Therefore youth pitchers who throw at a high velocity may be at increased risk for elbow injury.

It was also recommended that coaches take the velocity of their pitchers into account when measuring workloads in pitches. “The pitcher who throws 100 pitches in a game with an average velocity of 83 MPH would experience a greater volume of work compared with a pitcher throwing 100 pitches with an average velocity of 75 MPH.”
The harder a pitcher throws, at any age, means that there is going to be more stress.

Public Perceptions of Tommy John Surgery

Authors: Ahmad CS; Grantham, WJ; Greiwe RM

Questionnaires about Tommy John surgery were sent and filled out by 189 players, 15 coaches, and 31 parents. The results of the questionnaires show that there is a large gap between the realities and the perception of Tommy John surgery.

51% of high school athletes, 26% of collegiate athletes, 30% of coaches, 37% of parents believe that UCL surgery should be performed on players pre-injury to enhance performance. This has been shown to be false, surgery does not improve performance. Doctors would not perform unnecessary surgery on athletes.

A percentage of all groups believed that pitching control, speed, and performance improved in pitchers post surgery. 74% of high school athletes, 61% of college athletes, 93% of coaches and 92% of parents also believed that arm pain was greatly diminished post Tommy John.

Interestingly enough all groups underestimated the percentages of players that return to their previous level of play post surgery. The highest guess was the high school groups at 67%, while actual return to play rates are around 80%. It was also found that many greatly underestimated the time needed to rehab post surgery.

The misconceptions seemed highest in the younger individuals. Coaches and parent should be better educated on Tommy John surgery and what it can entail. Education will play a big part in helping players, coaches and parents make better decisions to keep pitchers healthy.


Biomechanical Comparison of Baseball Pitching and Long-Toss: Implications for Training and Rehabilitation (Open Access)


Authors: Fleisig, GS; Bolt, B; Fortenbaugh, D; Wilk, KE; Andrews JR

This study compared max-distance (long-toss) throws with flat ground throws on a line and pitching on a mound. Long tosses produced the greatest elbow and shoulder torques compared to flat ground and pitching. There were also changes in kinematics with long-toss throws compared to flat ground and pitching.

Progressive loading of the elbow and shoulder is needed to increase work capacity and velocity. Throwing long tosses does exceed the stress that is seen on a mound. This can be good because we don’t want pitching on a mound to be the most stressful event for a pitcher. We want to progressively push limits in practice so pitchers learn to apply more force in a controlled setting. Long toss is one of the ways this can be achieved.

More research on long toss is needed, ideally under a longer time period with more distances and with more athletes. This study also emphasized that clinicians and trainers should have a closer relationship when working with athletes who are coming back from surgery or injury.
Expand for Vocab

Elbow and Shoulder Torque – Measure of how much force is acting on the elbow and shoulder during rotation of pitching

Kinematics – branch of mechanics that describes the motion of points using math and geometry to figure the velocity or acceleration of various points of the body, in this case of a pitcher

Variability in Baseball Pitching Biomechanics among various levels of Competition 


Authors: Fleisig, G; Chu Y; Weber A; Andrews J

A total of 93 pitchers had 5 fastballs analysed: 20 youth, 19 high school, 20 college, 20 minor league, and 14 Major League pitchers. Kinematic, temporal, and kinetic parameters were examined with the goal of being able to compare individual standard deviations among groups.

A significant difference was found in six of the eleven kinematic parameters analysed: foot placement, knee flexion, pelvis angular velocity, elbow flexion, shoulder external rotation, and trunk forward tilt.

Youth pitchers had the largest variability in the placement of their front foot and of the amount of flexion at foot plant. A focus of practice for youth athletes should consider consistency of landing and flexion of the front leg.

There was no significant difference in the timing of biomechanics found between the various competition levels.

Standard deviations of variability tended to be the biggest for the youth pitchers and decreased as the level of competition increased. This means pitchers at high levels of competition exhibit less variability in their pitching motion. This is most likely because of increased years of repetition and greater neuromuscular development.

Baseball Pitching Biomechanics in Relation to Injury Risk and Performance (Open Access)


Authors: Fortenbaugh, Dave; Fleisig, Glenn S; Andrews, James R

This study reviewed all available literature on pitching biomechanics related to performance and injury. It is important to note that different institutions use an assortment of methods to measure biomechanics, which can make direct comparisons among them difficult.

This is a great review that touches on many aspects that should be of interest to coaches or trainers. Kinematics, kinetics, fatigue, youth pitchers, and pitch types are all covered along with what biomechanics markers have been shown to be helpful and harmful to pitchers across these studies. This is a great study for coaches and trainers who are looking to start educating themselves on biomechanics.

Remember that performance enhancement and injury prevention often go hand in hand when discussing pitching biomechanics.

Expand for Vocab
Pitching biomechanics – examining the forces applied to the body during the pitching motion to gain a greater understanding of how the body works and to reduce injuries

Kinematics – branch of mechanics that describes the motion of points using math and geometry to figure the velocity or acceleration of various points of the body, in this case of a pitcher

Kinetics – using physics to study motion and its causes, namely forces occurring in the pitching motion in this instance

Radio-ulnar joint supinates around ball release during baseball fastball pitching

Authors: Matsuo, Tomoyuki; Jinji, Tsutomu; Hirayama, Daisaku; Nasu, Daiki; Ozaki, Hiroki

A primer for pronation and supination: If you hold your arm up so your elbow is at 90 degrees with your thumb pointed at your ear, pronation would be moving the thumb to point at the front or anterior part of your body. Supination would be pointing your thumb behind you or at the posterior part of your body. It has been pointed out in previous studies that pronation of the hand/forearm is linked to internal rotation and supination in linked to external rotation.

The authors used a 16-camera–motion-analysis system at 1000 Hz to record the pitching motion of 20 healthy male semi-professional pitchers. A significant relationship was found between the pronation angle at the moment of ball release and the external rotation angle of the shoulder, as well as pronation angle and shoulder horizontal-adduction angle. There was a clear supination phase around the instant of ball release in all trials, but there was no consistent pattern among pitchers. The supination period lasted from just before to just after ball release.

It is reasonable to assume that the orientation of the palm correlates with the direction of the ball. After max external rotation, the arm goes into internal rotation at a very high speed. Nearing ball release, a supination phase may be needed for redirection of the ball towards its target.



The Impact of Fatigue on Baseball Pitching Mechanics in Adolescent Male Pitchers

Authors: Erickson, Brandon J; Sgori, Terrance; Chalmers, Peter; Vignona, Patrick; Lesniak, Matthew; Bush-Joseph, Charles; Verma, Nikhil; Romeo, Anthony

This study wanted to determine what kinematic factors changed as pitchers fatigued when throwing a simulated game. Pitching velocity, accuracy and pain levels were also tracked.

Adolescent males aged 13-16 thru a total of 90 pitches broken into groups of 15 pitches. As pitchers threw they experienced more fatigue, more pain and threw at lower velocities. Knee flexion at ball release progressively increased, although the researchers mention that it is likely a clinically insignificant change. Hip-to-shoulder separation significantly decreased as the simulated game went on as well.

Upper arm kinematics remained unchanged throughout, external rotation and total range of motion in the pitching shoulder significantly increased after pitching.

Because pitchers in the study experienced regular pain and fatigue the authors suggested that pain and fatigue may not be reliable measures of an impending injury.

Other interesting points in the studies included: 46% of subjects pitched for multiple teams, 39% pitched for more than 9 months a year, 61% participated in showcases and 11% had returned to the mound after being removed.

Keep in mind there is a big difference between pitchers who are adolescents and those whom are physically mature. It is an interesting finding that even those velocity did slightly decrease the kinematics of the throwing arm remained unchanged.

The Kinetic Chain revisited: New Concepts on Throwing Mechanics and Injury

Authors: Chu, SK; Jayabalan, P; Kibler, WB’ Press, J 

This paper looks at the entire kinetic chain of the pitching motion and breaks the pitching motion down into mechanical phases. Six mechanical phases are defined in the paper. It may be interesting for coaches and athletes to read what the phases the paper claims makes up the pitching motion to compare those to their own opinions.
One issue is the definition of the phases do not take into account the amount of variance that can be found in pitchers deliveries. It is also not clear if the paper suggests that all pitchers should throw exactly like the descriptions of the phases.

 Correlation of Throwing Mechanics with Elbow Valgus Load in Adult Baseball Pitchers

Authors: Aguinaldo, Arnel L; Chambers, Henry

This study examined pitching mechanics of sixty nine adult baseball players to try and determine what mechanics are correlated to increased valgus torque. Valgus torque is the stress put on the elbow, which is believed to cause UCL tears in some athletes.

Elbow valgus torque was most significantly influenced by peak shoulder external rotation, elbow flexion at peak valgus torque and elbow valgus loading rate.

Pitchers who initiated trunk rotation before front-foot contact exhibited significantly more elbow valgus torque than the pitchers who rotating their trunks after front-foot contact.

Elbow valgus torque increased with greater degrees of shoulder external rotation but decreased with more elbow flexion at ball release. It’s expected that higher shoulder external rotation will increase elbow valgus torque, but the finding that valgus stress is decreased with elbow flexion challenges the common belief that the elbow should be straighter during the delivery.

Fourteen of the pitchers threw sidearm. Those pitchers averaged a significantly higher average elbow valgus torque that pitchers who threw overhand. Suggesting pitching sidearm puts more stress on a pitcher’s arm than throwing overhand.

Youth Pitchers

Arm Pain in Youth Baseball Players: A Survey of Healthy Players (Open Access)

Authors: Makhni, Eric C; Morrow, Zachary S.; Luchetti, Timothy J; Mishra-Kalyani, Pallavi S; Gualtieri, Anthony P; Lee, Randall W Ahmad, Christopher S.

Of the 203 youth players surveyed 26% reported a prior injury to their throwing arm while 23% reported an injury that was concerned with overuse. 11% of players claimed to be currently playing with some sort of arm pain or discomfort. 26% of players stated that they were not having any arm pain.

Other statistics that stood out were 80% of players described having some sort of pain the day after throwing and 82% described having arm fatigue during a game or practice.
54% of players responded that arm pain at some point limited the number of innings they could play and 74% said pain limited how hard they could throw. Interestingly enough 71% did not believe that arm pain limited the number of leagues or teams they could participate in.

The Curveball as a Risk Factor for Injury: A Systematic Review

Authors: Grantham, W. Jeffery; Iyengar, Jaicharan J.; Byram, Ian R.; Ahmad, Christopher S.

The researchers aimed to review the current literature on the risk of throwing curveballs at a young age to see if it increases injury risk or not. 10 biomechanical studies and 6 epidemiologic studies were included in the analysis.

In the epidemiologic studies, the results were somewhat mixed but ⅗ found no association of arm injury/pain and throwing a curveball. All 5 studies suggested that increased amount of innings pitched as a significant risk factor related to arm pain.

Of the biomechanical studies none found increased force or torque at the glenohumeral joint when comparing throwing a curveball versus a fastball. There were differences found within forearm supination, greater supination was found in curveballs along with decreased pronator teres activation. Training supination should be included in youth practices, which is easiest to do in constraint drills.

“Youth pitchers with the highest pitch counts are likely the better pitchers on the team and therefore more inclined to throw a curveball earlier in their careers, further emphasizing overuse as a confounding variable.”
There is limited scientific support in this review to the belief that curveballs lead to injuries more often when compared to a fastball.

A Biomechanical Comparison of Youth Baseball Pitches: Is the Curveball Potentially Harmful?

Authors: Dun, Shouchen; Loftice, Jeremy; Fleisig, Glenn; Kingsley, David; Andrews, James

This study wanted to look just at youth pitchers and examine whether there was a difference in biomechanics between 5 fastballs, curveballs and changeups.

The fastball produced the highest elbow varus torque, shoulder internal rotation torque, elbow proximal force and shoulder proximal force. The curveball was the next highest and the changeup was the lowest. Wrist flexion torque and forearm supination torque were unsurprisingly highest for the curveball compared to a fastball or changeup.
These finding suggest that kinematic and temporal differences were found between all three pitch types but the data doesn’t not support the hypothesis that the curveball is potentially more harmful than the fastball.


Effects of Three Recovery Protocols on Range of Motion, Heart Rate, Rating of Perceived Exertion, and Blood Lactate in Baseball Pitchers During a Simulated Game

Authors: Warren, CD; Szymanski, DJ; Landers, MR

This study wanted to examine the effects of three different recovery protocols on range of motion, heart rate, rate of perceived exertion and blood lactate concentration in 21 D1 baseball players. The recovery methods were used in between innings of a simulated game where each pitcher threw 14 fastballs at 95% or higher intensity for 5 innings. They did this 3 times with 4 days between games.

Passive rest was defined as sitting in the dugout, active rest was using a pedal arm trainer and then EMS was used for the third group. Each between inning break was for 6 minutes.

The researchers found that the method of recovery did not affect range of motion but did significantly influence blood lactate concentration, heart rate and rate of perceived exertion.

Blood lactate levels did not change due to passive or active recovery methods but did decrease significantly due to EMS recovery. EMS was the preferred method by 18/21 participants. Active recovery had a negative effect on pitchers blood lactate levels. Heart rate decreased during all conditions but decreased significantly more after EMS and passive recovery.

It should be noted that even though blood lactate levels decreased with EMS the blood lactate levels were never high enough to cause skeletal muscle fatigue or decreased pitching velocity. If possible this study should be replicated under the unpredictable conditions of a live game.

Effect of Three Different Between-Inning Recovery Methods on Baseball Pitching Performance

Authors: Warren, CD; Brown, LE; Landers, MR; Stahura, KA

Active rest, passive rest or use of an EMS (electromuscle stimulation), which one is best for recovery? This study looked into use of active rest vs passive rest vs EMS between innings. EMS was shown to decrease BLa (Blood Lactate levels) and had the best self-reported recovery in pitchers. The case for using a EMS modalities post throwing can be made because they can used for longer time. This eventually lead us to discovering the Marc Pro, which we now have all of our pitchers use post throwing.
Expand for Vocab

Electromuscle stimulation – creating a muscle contraction using electric impulses. Often in a rehab setting using a TENS, Marc Pro or similar unit

Active rest – in this case the active rest used between innings was jogging

Passive rest – sitting in between innings on the bench

Blood Lactate levels – measure of the amount of lactic acid in the blood stream

Musculoskeletal overuse injuries and heart rate variability: Is there a link?

Authors: Gissleman, Angela Spontelli; Baxter, G. David; Wright, Alexis; Hegedus, Eric; Tumilty, Steve 

This study proposed a hypothesis that Heart Rate Variability is a useful measure to include when trying to measure the workload and possible overtraining that an athlete may be experiencing. Heart Rate Variability (HRV) is an indirect measure of the autonomic nervous system (ANS). In a not entirely understood why ANS activity has been shown to be important to the health and repair of somatic tissue after injury but there is believed to be a link.

HRV should be used in conjunction with psychological and biomechanical markers of stress in a more complete athlete profile. This may help improve our interpretation of an athlete’s response to training.
Admittedly previous research trying to link HRV to an athlete’s negative or positive adaptation to training has been conflicting. But since it is a relatively new technology it is worth looking into HRV tracking in relation to prevention of overuse injuries and rehabilitation of injured tissues to see if any patterns exist.

Weight Room and Workouts Training

Baseball Throwing Velocity: Comparison of Med ball and weight training

Authors: Newton, Robert; McEvory, Kerry

When deciding to train athletes with either medicine ball training or weight lifting it is more beneficial to use weight lifting. This study directly compared 8 weeks of medicine ball chest pass and overhead throws with bench pressing and pullovers and its effect of velocity. “…only group with a significant change in velocity pre- to post training was the weight training group.”

Medicine ball training can be beneficially but only as a supplement after the trainee can prove a high level of strength in the weight room. This is why we emphasize focusing on getting stronger in the weight room as a top priority.

Medicine Ball Training Implications for Rotational Power Sports (Open Access)

Authors: Earp, Jacob; Kraemer, William

When working with rotational athletes medicine ball training should be included as a supplemental to sport-generic exercises (ex; squats, bench press, deadlift). Coaches should also know if the sport is reactive (hockey), stationary (golf), or both (baseball) in nature when choosing medicine ball exercises to include in a training program.

It’s important to perform movements which mimic those in your sport and to keep the weight of the medicine ball in mind. Especially in highly coordinated movements. Excessive repetitions should be stayed away from as to not enforce poor motor patterns. The right dosage will need to be integrated with other strength work (ex squats) for the best results.

The Serape Effect: A Kinesiological Model for Core Training (Open Access)

Authors: Santana, Juan Carlos

This study proposes a new way of thinking about rotational training called the ‘serape effect’. The serape effect proposes thinking of how certain muscles involved in rotation (rhomboids, serratus anterior, external obliques and internal obliques) align in the form of an X on the trunk. This is similar to the idea of ‘muscular slings’ talked about in Anatomy Trains by Thomas Myers.
Rotational training is an interesting topic with some debate on how it is best trained in the weight room. Some coaches, such as Dan John, suggest that you can only train anti-rotation in the gym with the appropriate rotation training coming by practicing your sport. Training for rotation will be something that will be continued to be refined hopefully producing healthier and better athletes in the future.

Relationship Between throwing Velocity, Muscle Power, and Bar Velocity During Bench Press in Elite Handball Players

Authors: Marques, MC; van den Tillaar, Roland; Vescovi, JD; Gonzalex-Badillo, JJ

This study wanted to examine the relationship between velocity of a 3-step running throw in handball with dynamic strength, power, and bar velocity during a concentric-only bench press.

Each volunteer had used a free-weight barbell bench and started with an initial weight of 26 kg in the concentric-only portion of the lift. The weight was then increased in increments of 5-10 kgs. The last bearable load was determined as the athlete’s 1 rep max.

There were significant correlations between maximal strength, peak bar velocity, and peak power measures during concentric bench press and ball-throwing velocity. This would suggest that the 3-step throw velocity is related to an athlete’s ability to move lower external load with maximal velocity.

They do warn that the correlations are not higher because a throw requires more whole body coordination than a bench press. The study also included a sample size of 14 suggesting that there should be more research with a large group of athletes.


Coaching Instructions and Cues for enhancing Sprint Performance (Open access)

Authors: Benz, Adam, Winkelman, Nick; Porter, Jared; Nimphius, Sophia

Verbal instruction especially cues and feedback are essential to successful communication in coaching. This study looked specifically at sprint related cues but it is our belief that the types of cues matters in all sports. When comparing internal, external and neutral cues, external and neutral cues outperformed internal ones when looking at performance measures.

These results can be explained through the constrained action hypothesis (CAH). The CAH states “directing attention externally allows the motor control system to operate under nonconscious automatic processes by which movement occurs reflexively, leading to superior performance outcomes.” Future studies should investigate the effect of quantity of verbal cues on performance.

It worth exploring in baseball to use cues that are neutral or external in nature.


“Explode through your hips.” / “Explode off your back leg”


“Explode off the ground.” / “Explode off the rubber.”


“Complete the sprint as fast as you can.” / “Throw as hard as you can.”

Enhancing the Learning of Sport Skills through external-focus feedback

Authors: Wulf, G; McConnel, N; Gartner, M; Schwarz, A

What we took from this study:

  • Internal cues/feedback are instructions that refer to the coordination of their body movements / performers appear to actively intervene in the control processes, resulting in degraded performance and learning
  • External cues/feedback direct the learners’ attention to the effects of their movements on the environment (apparatus, implement) / performers use more automatic control processes when attending to the movement effect than when attending to the actual movements
  • This study reviewed some literature on previous studies on cues and included two experiments.
  • One saw that external-focus feedback had better accuracy and retention scores in a tennis style volleyball serve.
  • The second study looked at frequency of feedback in using external and internal cues. More often external feedback (100%) was more effective that less often (33%) which was the reverse of what happened in the internal-focus feedback group.

When dealing with athletes this study suggests external cues are more beneficial to learning a skill than internal cues.

Frequent external-focus feedback enhances motor learning (open access)

Authors: Wulf, G; Chiviacowsky, S; Schiller, E; Avila, L

What we learned from this study:

  • So far there is little evidence that feedback/cues provided after every practice trail causes learners/athletes to become dependent on it.
  • Adoption of an external focus has been shown to facilitate automaticity in movement control and efficiency.
  • Directing attention inward (internal cues) tends to result in conscious control attempts that constrain the motor system, disrupt automaticity and lead to superfluous muscular activity.
  • 48 children between the ages of 10-12 were broken into four groups. External cues (100% or 33%) and Internal cues (100% or 33%) were used with a focus on form for a soccer throw in. External-focus feedback provided after every trail (100%) resulted in more effective learning than less frequent feedback (33%).

More feedback was better but it’s important to keep the context. This was in relation to 10-12 year olds in gaining better form. Which would be different than a 20 year old who is working on control/accuracy. Keep in mind not only who you are teaching to but also if you are giving feedback/cues on form, performance or result measures.

More research is needed on how the frequency of external feedback affects the accuracy/control of certain skills in older adolescents or young adults.

Increased Jump Height and reduced EMG activity with an External Focus

Authors: Wulf, Gabriele; Dufek, Janet S; Lozano, Leonardo; Pettigrew, Christina

Previous research has show jump height increases when athletes were given an external focus versus an internal or no focus. This study wanted to examine whether there were underlying neurophysiological changes based on EMG with a change of focus.

Electrodes were placed on the following right side leg muscles: rectus femoris (RF), bicep femoris (BF), vastus lateralis (VL), lateral gastrocnemius (LG), and the anterior tibialis (AT). Each athlete had 10 jump trials for both the internal and external focus conditions.

The group with the external focus jumped an average of 1.4 cm higher relative to an internal focus. EMG activity was lower with the external focus for all muscle groups except for the lateral gastrocnemius. The timing of the muscle activation did not change significantly between the internal and external focus.

This results in decreased EMG activity, combined with more effective results (higher jump height) as a result of an external focus. The data also suggests that external focus provides the most efficient coordination of muscles.

Shoulder Injuries

Risk Factors for Shoulder and Elbow Injuries in High School Baseball Pitchers

Authors: Tyler, TF; Mullaney, MJ; Mirabella, MR; Nicholas, SJ; MCHugh, MP

Baseline testing found: athletes dominant arms had less internal rotation (IR), more external rotation (ER) but minimal difference in total range of motion (ROM) in comparison to non-dominant arms.

-This was a study on adolescent (High School) pitchers with relatively low pitching volume whose musculoskeletal systems might not have properly adapted to a pitching motion. There was no conclusive indication that excessive loss of IR or total ROM increased risk of shoulder or elbow injuries. But this does warrant further research of IR and ROM in pitchers of specific populations.

-Preseason supraspinatus weakness (one of four rotator cuff muscles that abducts the shoulder) was related to an increased risk for major injuries (>3 missed games). A training focus should be made of strengthening the supraspinatus (and rotator cuff) in an attempt to prevent injury.

Expand for Vocab
Internal rotation (IR) – term referring to rotation towards the center of the body. If an athlete was laying of their back with their hand at 90 degrees pointing upward, internal rotation would be the motion of the hand going towards the hip.

External rotation (ER) – term referring to rotation away from the body. If an athlete was laying on their back with their hand at 90 degrees pointing upward, external rotation would be the motion of the hand going towards the hip.

Total range of motion (ROM) – Combining internal and external rotation into one measurement

Supraspinatus – one of the four muscles of the rotator cuff muscles. Abducts the arm at the shoulder

Rotator Cuff – group of tendons and muscles in the shoulder that provide stability to the shoulder and connect the upper arm (humerus) to the shoulder blade (scapula)

Preseason Shoulder Strength Measurements in Professional Baseball Pitchers

Authors: Byram, Ian; Bushnell, Brandon; Dugger, Keith; Charron, Kevin; Harrell, Frank; Noonan, Thomas

What we learned from this study:

This study looked at Major and Minor league pitchers from the years 2001-2005. Strength was assessed for prone internal rotation (IR), prone external rotation (PER) seated external rotation (SER) and supraspinatus (one of four rotator cuff muscles that abducts the shoulder).

  • No players were eliminated from the study because of prior injury.
  • There was no control for overuse or type of pitches thrown.
  • There was a significant association between shoulder external rotator and supraspinatus weakness and injury requiring surgery.
    • 70 injuries were found in 50 players, 10 player suffered injuries in multiple seasons
    • 42 injuries were treated nonoperatively, 28 were treated surgically
        • Preseason strength data may help identify players at risk for injury

During throwing motion the glenohumeral joint relies on the rotator cuff and surrounding musculature such as latissimus dorsi and pectoralis major to resist distraction forces. Weakness of the external rotators can lead to a lack of muscular control during lack cocking and deceleration. Therefore strength training plans should be formulated for the rotator cuff as a preventive measure to injury.

Posterior Shoulder Capsules are Thicker and Stiffer in the Throwing Shoulders of Healthy College Baseball Players

Authors: Takenaga, T; Sugimoto, K; Goto, H; Nozaki, M; Fukyoshi, M; Tsuchiya, A; Murase, A; Ono, T; Otsuka, T

It has been reported that the posterior (back) shoulder muscles are thicker in throwing arms than non throwing, which has a relationship to GIRD. This study used Shear-wave ultrasound elastography to measure the stiffness of the thickened capsules.

The posterior capsule, below the infraspinatus, had significantly greater thickness and elasticity (stiffness) in the throwing shoulder vs non throwing. The posteroinferior capsule, below the teres minor, was also significantly thicker and stiffer in the throwing shoulder than non throwing. This suggests that capsular elasticity could more strongly affect GIRD than capsular thickness. More studies are needed with a bigger group size to see if measuring shoulder elasticity in this manner can help identify players at risk.
We want to be able to look at differences in athletes and distinguish common adaptations to repetitive throwing from pathological changes. More progressive studies, like this use, using new non invasive modalities are encouraged.

Relationship between maximum shoulder external rotation angle during throwing and physical variables (Open Access)

Authors: Miyashita, Koji; Urabe, Yukio; Kobayashi, Hirokazu; Yokoe, Kiyoshi; Koshida, Sentaro; Kawamura, Morio; Ida, Kunio

40 high school position players and pitchers participated in a study looking at the relationship between maximum shoulder external rotation (MER) during throwing motions, passive ROM and kinematic variables at stride foot contact (SFC).

MER showed a significant moderate linear correlation with ER and extension angles at SFC in the early cocking phase. It was suggested because of these findings to avoid excessive shoulder IR and extension angles at SFC and to strengthen the internal rotator muscles. There is also a need to maintain passive ROM of ER in a normal range.
Because of the limitations of the study design the researchers were unable to conclude whether the increase of MER was a cause or result of the physical and kinematic variables. More research is needed to find factors contributing to the increase of MER.

Shoulder Adaptations Among Pitchers and Position Players Over the Course of a Competitive Baseball Season

Authors: Laudner, KG; Lynall, R; Meister, K

This study compared 16 pitchers and 16 position players before and after a 140 game season. They were measured in: scapular upward rotation (0,60,90,120 degrees), forward scapular posture. glenohumeral head (GH) range of motion (horizontal adduction, bilateral GH internal rotation ROM). The pitchers in this study completed a team-mandated shoulder exercise program during the season, this was not required of the position players

  • No significant differences in GH horizontal adduction were found
  • No significant differences in  bilateral internal rotation ROM
  • Forward scapular posture and scapular upward rotation at 0 degrees and 120 degrees of humeral elevation were not significantly different
  • Pitchers developed significantly less scapular upward rotation at 60 degrees and 90 degrees of humeral elevation compared to position players

Proposed reasons for this were changes in length tightness and strength of various periscapular muscles such as pectoralis minor, rhomboids, and levator scapulae. Strengthening and stretching of these muscles during the season was suggested.

More studies are needed in comparing ROM of pitchers versus position players over longer time frames such as pre and post season.

Glenohumeral Rotational Range of Motion in Collegiate Overhead-Throwing Athletes During an Athletic Season (Open Access)

Authors: Dwelly, Priscilla; Tripp, Brady; Tripp, Patricia; Eberman, Lindsey; Gorin, Steven

This was an observational study looking at 29 healthy baseball athletes and 19 healthy softball athletes. Measurements were taken over 3 time during one athletic season: prefall, pre spring and post spring. The measures were of glenohumeral ROM: external rotation (ER), internal rotation (IR), total arc and GIRD.

Athletes had increased ER and total arc (because of the ER gains) but their IR did not change significantly over their season.

Both calculations for GIRD (IR difference between dominant and nondominant arms and percentage of total arc) appeared to quantify a specific characteristic of relative ROM, yet they reflected different deficits. More studies are needed to compared the these two measurements of GIRD long term.


Differences in Scapular Upward Rotation between Baseball Pitchers and Position Players

Authors: Laudner, KG; Stanek, JM; Meister K

Baseball pitchers have significantly less scapular upward rotation than do position players at high angles of humeral elevation (60 & 90).

The body will compensate through loss of range of motion in the scapula. Which can impact the function of the kinetic chain and put the shoulder at risk for instability, impingement and further injury

It was suggested that muscle tightness of the rhomboids, levator scapula and pectoralis minor may limit how much upward rotation is available. Because of this we suggest athletes use a lacrosse ball to massage these areas before throwing.

Further studies are needed to investigate the role that joint laxity and muscle fatigue play in the differences of upward rotation of the scapula.

Ground Reaction Forces

Rate of Force Acceptance as an Injury Prevention Strategy in Athletic Populations (Open Access)

Authors: Jeronimo, Luis; Pelot, Tim

Looking at ground reaction forces in previous studies it suggests that injuries are typically correlated with eccentric muscle actions. Making the ability to rapidly absorb force a key part of injury prevention. Having poor deceleration may be a precursor to injuries in the lower half, evidence suggests that most ACL injuries occur during deceleration, pivoting or landing. If certain muscles are not able to absorb the force effectively the ligament may be forced to pick up the slack.

It was suggested that training with light and heavy loads (15-35% and 85-90% of 1RM) in certain exercises may help train athletes in injury prevention. Training with lighter loads leads to faster movements while heavier loads lead to higher force production.

Training to tolerate high eccentric forces in the lower half and arm may play a key role in injury prevention in an athlete’s training.

Stride Leg Ground Reaction Forces Predict Throwing Velocity in Adult Recreational Baseball Pitchers

Authors: McNally, Michael P.; Borstad, John D.; Onate, James A.; Chaudhari, Ajit M.W 

18 former competitive baseball players threw off of a mound to measure ground reaction forces under both the drive and stride legs.

Stride leg ground reaction forces during the arm-cocking and arm-acceleration phases were strongly correlated with ball velocity. Drive leg ground reaction forces showed no significant correlations.

More specifically the ground reaction forces of the stride leg in the vertical and posterior directions, as well as resultant ground force, were strongly correlated to peak wrist velocity. Meaning that force against the direction of the throw appears to contribute strongly to velocity as it explained 61% of the variance in wrist velocity.

Not all of the baseball players in the study were pitchers previously and none of the players were currently playing competitively. These findings do suggest that the study should be replicated with pitchers who are playing competitively to compare the results.

It also is suggested that improving eccentric knee flexion control through single-leg exercises and plyometrics would improve stride leg forces and ball velocity.

Countermovement Jump Height: Gender and Sport-specific Differences in the force-time variables

Authors: Laffaye, Guillaume; Wagner, Phillip; Tombleson, Tom 

This study looked at different markers of the vertical jump to see what differences there were with different genders and athletes who play different sports.

The study looked critically at average eccentric rate of force development, total time, eccentric time, ratio between eccentric and total time, and average force. These were taken from force-time curves in a countermovement jump.

Athletes used jumping strategies which reveal specific constraints of the sport that they played. It was found that football and baseball players tended to display more explosive profile. Usually having high values of average eccentric rate of force development, average force as well as higher value in jump height. This suggests that even though football and baseball aren’t focused on vertical jumping they require more maximal rested explosive muscular actions which translates to a higher vertical jump. This could mean that the force component is dependent on the muscle-tendon system regardless of the direction of the ground reaction force.

Correlation of Throwing Velocity to the Results of Lower-Body Field Tests in Male College Baseball Players

Authors: Lehman, Graeme; Drinkwater, Eric J; Behm, David

There is a lack of research examining throwing velocity with frontal and unilateral exercises. This study aimed to examine a number of lower-body tests with velocity: medicine ball scoop toss, medicine ball squat throw, bilateral vertical jump, left leg vertical jump, right leg vertical jump, broad jump, triple board jump, hop and stop from left to right, hop and stop from right to left, lateral to medial jump right (LMJR), lateral to medial jump left (LMJL), 10-yd sprint, 60-yd sprint, and both left and right single-leg 10-yd hop for speed.

The lateral to medial jumps were found to have a consistent correlation to high velocity in both right and leg handed throwers. The lateral to medial jump is a unilateral jump in the frontal plane that mimics the stride.

This finding suggests that the ability to push of the trail leg is correlated to velocity. In theory having a powerful leg drive sequenced into the pitching delivery would enable more energy to be transferred up the kinetic chain. This is in agreement with the findings of MacWilliams et al. in “Characteristic ground-reaction forces in baseball pitches”.

Future studies should examine different training in the frontal plane to see if increases throwing velocity occur.

Characteristic Ground-Reaction Forces in Baseball Pitching (Open Access)

Authors: MacWilliams, Bruce; Choi, Tony; Perezous, Mark; Chao, Edmund; McFarland, Edward

This study found high correlations between push off and landing forces with different sections of the pitching delivery.  Specifically push-off forces during with cocking phase and the landing force with ball release.

Within the group of pitchers there was a lot of variance. Some pitchers exhibited increasing ground forces with an increase in wrist velocity and others demonstrated the opposite. The more force they produced the slower wrist velocity. This likely means that the amount of force you can produce shouldn’t be the sole focus of training but the timings of those forces.

The authors also found that pitchers that produced the highest forces (normalized to body weight) threw the fastest. Which would contradict the theory that pitchers should have a ‘controlled fall’.

Timing of the Lower Limb Drive and Throwing Limb Movement in Baseball Pitching (Open Access)

Authors: Elliott, Bruce; Grove, Robert; Gibson, Barry

This study wanted to examine if ground reaction forces of the back leg changed during the windup versus the stretch position and between throwing a fastball or curveball.

Vertical and Horizontal force of the back leg reached its peak during the arm cocking phase for both the fastball and curveball in both the stretch and windup.

Some interesting difference appeared when splitting the pitchers into high velocity and  low velocity groups. The maximum forces were similar with both groups peaking at arm cocking. The slower pitchers seemed to begin their back leg drive earlier. The forces decreased faster between the cocked position and stride-foot landing for the slower pitchers. The faster pitchers had higher force readings on their back let at front-foot landing. The researchers found that the faster pitchers had the ability to drive the body over a stabilized front leg.

This study only included 6 pitchers. Further research should be completed with a larger sample size and with a force plate at front foot landing as well.
The researchers found that pitchers should find a balance between ‘pushing off as hard as they can’ and ‘having a controlled fall.’ Trunk rotation and forward movement of the throwing arm did not occur until after the stride foot had planted.

Other Throwing Sports

Strength and Power Correlates of Throwing Velocity on Subelite Male Cricket Players

Authors: Freeston, JL; Carter, T; Whitaker, G; Nicholls, O; Rooney, KB

This study aimed to examine difference strength and power measurables to see which were correlated to cricket throwing velocity.

Dominant leg Lateral to Medial Jump and dominant side medicine ball rotational throw had the highest correlations to stretch and shuffle throw velocity. Followed by medicine ball chest pass.

A non-significant trend was observed for vertical jump height. But after a multiple regression analysis vertical jump height reached statistical significance (r=0.51). The study found medicine ball rotation throw velocity and medicine ball chest pass distance to explain 70% of the variance.

Medicine ball training has been shown to be correlated to throwing velocities meaning that is should be included in a well rounded S & C program. A follow up study to compare the results of the same tests with elite cricket or baseball players would provide an interesting comparison.

Predicting the throwing velocity of the ball in Handball with Anthropometric variables and isotonic tests 

Authors: Debanne, T; Laffaye, G

The researchers wanted to investigate the level of influence of anthropometric, handball-specific anthropometric variables, and upper-limb power and strength on throwing velocity. They attempt to predict velocity based on those factors using multiple regression methods.

Positive correlations were found between ball velocity and general anthropometric measures (body mass, height, BMI, lean mass). Handball specific parameters (Hand perimeter, finger span, ring finger length, middle finger length, arm span) were found to be lower correlated that previous studies suggest.

Correlation of strength variables (force, power, and bar velocity in the bench press, medicine-ball throwing performance) ranged from .45 to .80. With medicine-ball throwing being the highest. The medicine ball throw was done kneeling, holding the ball over their heads, with distance being measured.

Ball velocity had a high correlation (.65) with maximum power in the bench press. A strong correlation (.6) was also found between bar velocity at 20 kg. Bench press at lower loads showed better correlations than higher loads when examining power and force outputs.

The best anthropometric model was only able to explain 41% of the total variance. A model including the medicine ball throwing performance and body mass (the highest anthropometric measurement) predicted 72.76% of total variance. The highest model included body mass, medicine ball performance and force output at 20 kg at 74.28%.