Comparing the Unconventional Marshall Pitching Motion to a Refined Conventional Pitching Motion

This report compares and contrasts two different baseball pitching motions as related to their athletic fitness levels. To clarify, these pitching motions will henceforth be referred to as the “Unconventional Marshall Motion” and “Refined Conventional Motion.” As demonstrated by the case subject, biomechanical hallmarks of each motion and their applied techniques will be detailed in later sections.

Scientific biomechanical study of baseball pitching poses some significant challenges. The fastest human athletic activity known, elite level pitching arm accelerations take place in less than two hundredths of a second. Recording body segments moving at these speeds requires equipment that operates at micro-second levels…tools like high speed video, high speed film and, more recently, motion sensors.

Although no two athletes perform the baseball pitching motion in exactly the same way there are commonalities in deliveries. Researching a more efficient and anatomically sound way to throw is difficult because the sample size is always one: one pitcher. This study is unique because it is the focus of a professional caliber athlete who has learned two distinct ways to throw.

The study subject is a 23 year-old male, 6′-4, 215-pound, left-handed pitcher, previously drafted by a Major League Baseball club in 2003. From June 2004 to May 2007 the subject participated in three years of intensive physical training while learning an alternate mechanic under the direct guidance and supervision of Dr. Mike Marshall. In the eighteen months prior to this study the subject reports experiencing significant pain in the left anterior shoulder. Medical evaluation revealed signs of partial shoulder dislocation that correlates with the subject’s training experience. Portions of this study were designed specifically to identify stressors in the Unconventional Marshall Pitching Motion that might have contributed to anterior shoulder pain.

Methodology & Scientific Assumptions When analyzing the pitching motion and assessing the value of a model for the perfect pitching motion there are individual-specific issues that need to be assessed for each pitcher; they are like fingerprints and each is unique. Due to variances of an individual’s skeletal and muscular structure his pitching technique bears a unique biomechanical signature. It is suggested that assessments be made on each individual, focusing on the overall stress conduit relative to their physical ability to perform, repeat, and maintain the specific movements of their technique. To say that there is a perfect model for pitching is a misnomer and should be viewed as such. There have been cases of longevity among pitchers and their pitching motions over the years. Most of the case subjects have physically trained their bodies to accept specific amounts of stress at certain points of the kinetic chain sequence. The repetitive movements specific to their motion are very consistent and maintain that consistency throughout their career, thus decreasing the chance of mistake or injury.

In this study we are examining the consistencies, durability potential, stress factors, kinetic chain sequences and overall injury parameters that would present potential injury or decreased longevity to the subject athlete, as compared between the Refined Conventional Motion and the Unconventional Marshall Pitching Motion. The study collected objective data utilizing 3D-motion tracking sensors strategically placed on key body segments to extract biomechanical information necessary for comparative analysis. This analysis was not designed to provide an indication of the subject’s ability to perform a given task (though some insights about inherent ability were gained). Rather it is a measure of the relative efficiency of the ability of the two motions to efficiently transfer energy from one body segment to the other and the fitness levels needed to perform each motion as demonstrated by the subject.

All objective data was obtained using the E-Factor motion capture system, and was systematized in part through analysis of elite athletes using data gathered from nine years of studies. Fitness levels (muscle strength relative to specific actions or motions) and relative ideals used in the study were derived from anatomically correct kinetic chaining sequences. Ideal sequencing was determined in part through longevity of the subjects from past studies and from existing Torque Stand studies involving over 48,000 test cases. Using integrated system software, fitness levels were evaluated on the basis of the sum of muscle torques developed by main muscle groups under static conditions (ISI – isometric strength indicator). Measurements were based in part on previous studies using an isometric muscle torque stand (local make), which enabled the direct measuring of torques for flexors and extensors of elbow, shoulder, knee and hip joints and flexors and extensors of trunk. Angle positions for all joints were 90 deg (with 180 deg meaning full extension) with the exception of shoulder joint (45 deg).

The stand enabled each group of muscles to be measured with simultaneous elimination of the influence of any other forces on the result [Jaszczuk et al.1987]. Kinematic anatomical sequencing was examined by recording and comparing Maximum Rotational Speeds and Progressive Speed Gains for each major body segment, measured in degrees per second. Directional speeds in the X, Y, and Z planes were measured. Hand speeds, relative tempo, posture at stance, posture at balance point, posture at hand break, posture at toe touch, posture at delivery and posture at finish were all derived from the data. The biomechanical structures were analyzed and then mathematically assessed to determine the efficiency of the two specific pitching motions. The diagram below shows the coordinate system used by the E-Factor analysis software used in this study. The axes shown are used to determine spatial position as well as orientation. All movements are recorded using sensors placed on the body that are constantly monitored by an electromagnetic global reference frame surrounding the athlete.

Comparative Accuracy & Efficiencies Summary Data obtained from this study lead to the conclusion that the Refined Conventional Motion is: 1) more accurate, and 2) more efficient, when compared to the Unconventional Marshall Motion. As demonstrated by the subject it was found that considerably lower hand speed efficiencies were generated in the Unconventional Marshall Motion as compared to the Refined Conventional Motion. Based on data compiled for both accuracy and efficiency the subject’s hand speed generated by the Unconventional Marshall Motion was 25.4 % and the hand speed generated by the Refined Conventional Motion was 58.3%. Accuracy in the pitching motion references the proportional number of times that the pitcher is likely to deliver pitches to the strike zone. Objectively comparing the Refined Conventional Motion to the Unconventional Marshall Motion it was found that the test subject was more likely to be inconsistent in delivering pitches to the strike zone when utilizing the Unconventional Marshall Motion based on inconsistencies in delivery repeatability as measured by relative efficiencies and variations in driveline displacement.

Prior to release, using the Unconventional Marshall Motion, a significant disconnect of the sequential energy transfer was noted, disrupting the kinematic sequencing from the arm to the wrist. Also noted is a major 7.5 inch shift of the Center of Gravity to the right side lead leg position. This shift (along with the arm lagging significantly behind torso rotation) places significant stress on the shoulder capsule and was noted to correspondingly decelerate the arm, wrist and hand. Ultimately this would result in lower velocity of the baseball. At the point of ball release, using the Unconventional Marshall Motion, the subject’s Pelvis Rotation was 119.93 degrees per second and the Head Side Bend was -27.21 degrees per second and the overall Upper Body Bend was -48.61 degrees per second indicating significant lateral displacement of the body before, during, and after release. This inefficiency correlates with lowered release velocities as torsion force is directed laterally away from the target rather than towards it.

Unconventional Marshall Motion: Analysis Summary Date of Test: 14 January 2008 Location: Mtn. Pointe Three-dimensional motion tracking sensors were strategically placed on key body segments to extract data. Breakdown of efficiency scores follows. (Higher scores represent a more biomechanically efficient motion.) Efficiency Summary HandSpeed 25.4% Tempo 69.3% Posture at Stance 64.2% Posture at Balance Point 55.1% Posture at Hand Break 53.3% Posture at Toe Touch 51.2% Posture at Delivery 26.8% Posture at Finish 31.8% Unconventional Marshall Motion: Rotational Speeds and Progressive Speed Gains The graph and charts in this section depict the relative speeds and sequencing of the subject’s left side joints, prior to and at ball release. Efficient ballistic athletic events will follow a sequential delivery and forward passage of peak joint linear velocities from the ground up through the wrist and hand. The graph below represents the trial kinematic sequence from address to finish. The red line represents rotational speed of the pelvis. The green line represents rotational speed of the upper body.

The blue line represents rotational speed of the arm. The yellow line represents rotational speed of the hand. Max Rotational Speed (degrees/sec) Segment Subject Ideal Pelvis 570.27 500.00 Upper Body 822.90 850.00 Arm 5197.09 5000.00 Hand 3248.23 7000.00 Progressive Speed Gains (degrees/sec) Segment Subject Ideal Pelvis to UBody 570.27 350.00 UBody to Arm 822.90 4150.00 Arm to Hand 5197.09 2000.00 Kinematic Sequence Ideal Kinematic Sequence: Pelvis, Torso, Arm, Hand Subjects Kinematic Sequence: Pelvis, Torso, Hand, Arm It is notable that the subject peaks his linear hip, shoulder, elbow and wrist velocities in proper sequence but there is a significant drop in peak velocities at the elbow and wrist joints approximately 0.4 seconds before ball release. Each body segment in the kinematic sequence must transfer energy efficiently to the next segment. Power created, beginning with the feet, is transferred through the legs, pelvis, torso and arms to be delivered at the hand or sports implement. Each segment adds its distinct energy increase to total power. It is important that energy increases transfer smoothly and in proper sequence. Correct sequencing allows for a biomechanically fluid motion that contributes more power, explosiveness and efficiency while reducing workload and risk of injury.

Abrupt gains or losses from one segment to the next can be indicative of potential problem areas or specific injury risks. Unconventional Marshall Motion: Hand Speeds The graph and chart below depicts the subject’s hand speed during the trial from stance to finish. The red line represents the hand speed towards or away from the target (X-Axis). The green line represents hand speed laterally across the body (Y-Axis). The blue line represents hand speed up or down (Z-Axis). The yellow line represents overall hand speed and is calculated based on all three vectors (X-, Y-, and Z-Axes) Overall Hand Speed Efficiency: 25.4% Direction Max (MPH) Min (MPH) At Delivery (MPH) Res. At Delivery (%) X Direction 46.62 -10.05 +35.33 76.1 Y Direction 9.88 -22.75 -20.97 -45.1 Z Direction 21.15 -28.36 -21.67 -46.7 Resultant 47.02 0.07 +46.45 n/a In the table above: · X Direction defines movement toward and away from the target. Positive values indicate hand speed toward the target. Negative values indicate hand speed away from the target. · Y Direction defines movement toward and away from the body laterally. Positive values indicate lateral hand speed away from the body. Negative values indicate lateral hand speed toward the body. · Z Direction defines movement up and down. Positive values indicate hand speed upwards. Negative values indicated hand speed downwards.

Overall hand speed efficiency is an indicator of both accuracy and biomechanical efficiency. The higher the score the more likely any given pitch will be delivered to the target. Higher scores also predict less fatigue and less injury risk. The subject’s overall hand speed efficiency of 25.4%, using the Unconventional Marshall Motion, places him at risk for both substantial fatigue and injury and predicts that he will have difficulty in throwing strikes with this delivery. Unconventional Marshall Motion: Body Posture at Toe Touch Toe touch is defined as the moment when the stride foot lands and weight has transferred in a straight line towards the target. Simultaneously the pitcher should initiate forward movement of the throwing arm and rotation of the pelvis and upper body. Posture at toe touch is vital if a pitcher is to be in a strong, athletic position where upper and lower body can work together to transfer energy efficiently. Overall Efficiency of Body Posture At Toe Touch: 51.2% Body Segment Subject Posture Ideal Posture Difference Pelvis Rotation 35.60 Open 45.00 Open 9.60 Closed Spine Rotation 19.91 Closed 15.00 Closed 4.91 Closed Upper Body Rotation 15.63 Open 30.00 Open 14.37 Closed Head Rotation 70.31 Open 75.00 Open 4.69 Closed Trail Foot Rotation 84.20 Closed 35.00 Open 119.20 Closed Lead Foot Rotation 94.93 Open 80.00 Open 14.93 Open Pelvis Forward-Backward Bend 0.77 Forward 2.00 Forward 1.23 Backward Spine Forward-Backward Bend 0.51 Forward 6.00 Forward 5.49 Backward Torso Forward-Backward Bend 0.86 Forward 8.00 Forward 7.14 Backward Head Forward-Backward Bend 3.71 Forward 10.00 Forward 6.29 Backward Trail Foot Dorsi-Plantar Flexion 69.28 Up 25.00 Up 44.28 Up Lead Foot Dorsi-Plantar Flexion 6.22 Up 0.00 Up 6.22 Up Pelvis Side Bend 1.10 Lead 3.00 Lead 1.90 Trail Spine Side Bend 9.00 Trail 5.00 Trail 4.00 Trail Torso Side Bend 7.70 Trail 2.00 Trail 5.70 Trail Head Side Bend 27.50 Lead 5.00 Trail 32.50 Trail Trail Foot Pronation-Supination 5.52 Outward 20.00 Inward 25.52 Outward Lead Foot Pronation-Supination 9.38 Inward 0.00 Outward 9.38 Inward (Note: All measurements in degrees; Data taken from frame 743)

Unconventional Marshall Motion: Body Posture At Ball Release Delivery or release point is defined as the instant in which the pitcher’s hand is furthest from the body in the direction of the target while the middle finger is still in contact with the ball. Every athlete must reach this point immediately at ball release. Overall Efficiency of Body Posture At Ball Release: 26.8% Body Segment Subject Posture Ideal * Posture Difference Pelvis Rotation 122.64Open 90.00Open 32.64 Open Spine Rotation 0.69 Closed 0.00 Open 0.69 Open Upper Body Rotation 138.62 Open 90.00 Open 48.62 Open Head Rotation 140.72 Open 90.00 Open 50.72 Open Trail Foot Rotation 209.78 Closed 80.00 Open 289.78 Closed Lead Foot Rotation 93.24 Open 80.00 Open 13.24 Open Pelvis Forward-Backward Bend 15.72 Forward 10.00 Forward 5.72 Forward Spine Forward-Backward Bend 24.50 Forward 15.00 Forward 5.72 Forward Torso Forward-Backward Bend 38.89 Forward 25.00 Forward 13.89 Forward Head Forward-Backward Bend 26.14 Forward 2.00 Forward 24.14 Forward Trail Foot Dorsi-Plantar Flexion 42.16 Upward 85.00 Upward 42.84 Downward Lead Foot Dorsi-Plantar Flexion 9.00 Upward 0.00 Upward 9.00 Upward Pelvis Side Bend 2.43 Trail 0.00 Trail 2.43 Trail Spine Side Bend 48.94 Lead 10.00 Trail 58.94 Trail Torso Side Bend 44.38 Lead 10.00 Trail 54.38 Lead Head Side Bend 26.98 Lead 0.00 Trail 27.98 Lead Trail Foot Pronation-Supination 2.04 Outward 7.00 Inward 9.04 Outward Lead Foot Pronation-Supination 34.52 Inward 0.00 Outward 34.52

Inward (Note: All measurements in degrees; Data taken from frame 805) * Note that in the subject’s graphs and charts derived from the E-Factor system the word IDEAL is used. This is not based on a conceptualized model but rather a computation of all of the analysis done in the past of subjects who scored high with respect to overall fitness to their specific athletic endeavor. It was noted that the subject’s linear movement reaches peak approximately 0.3 seconds prior to ball release and his rotational momentum reaches peak at ball release. This indicates a pre-release linear braking motion of the body. This action will place higher stress on the anterior of the shoulder joint as it positions itself for energy transfer to the elbow, wrist and hand. The following chart and robotic representation of the subject addresses the relative positions of shoulders vs. hips at ball release using the Unconventional Marshall Motion. It is noted that at ball release the subject’s shoulders are only 17 degrees forward of his hips. This indicates poor utilization of trunk rotational torque in the delivery of the pitch. Refined Conventional Motion: Analysis Summary Date of Test: 14 January 2008 Location: Mtn. Pointe Three-dimensional motion tracking sensors were strategically placed on key body segments to extract data. Breakdown of efficiency scores follows. (Higher scores represent a more biomechanically efficient motion.)

Efficiency Summary

Hand Speed 58.3%

Tempo 66.5%

Posture at Stance 51.9%

Posture at Balance Point 44.1%

Posture at Hand Break 44.3%

Posture at Toe Touch 37.8%

Posture at Delivery 28.1%

Posture at Finish 31.0%

Refined Conventional Motion: Rotational Speeds and Progressive Speed Gains The graph and charts in this section depict the relative speeds and sequencing of the subject’s left side joints, prior to and at ball release. Efficient ballistic athletic events will follow a sequential delivery and forward passage of peak joint linear velocities from the ground up through the wrist and hand. The graph below represents the trial kinematic sequence from address to finish. The red line represents rotational speed of the pelvis. The green line represents rotational speed of the upper body. The blue line represents rotational speed of the arm. The yellow line represents rotational speed of the hand. Max Rotational Speed (degrees/sec) Segment Subject Ideal Pelvis 619.96 500.00 Upper Body 868.52 850.00 Arm 5905.61 5000.00 Hand 4391.86 7000.00 Progressive Speed Gains (degrees/sec) Segment Subject Ideal Pelvis to UBody 248.56 350.00 UBody to Arm 5037.10 4150.00 Arm to Hand -1513.95 2000.00 Kinematic Sequence Ideal Kinematic Sequence: Pelvis, Torso, Arm, Hand Subjects Kinematic Sequence: Pelvis, Torso, Hand, Arm Each body segment in the kinematic sequence must transfer energy efficiently to the next segment.

Power created, beginning with the feet, is transferred through the legs, pelvis, torso and arms to be delivered at the hand or sports implement. Each segment adds its distinct energy increase to total power. It is important that energy increases transfer smoothly and in proper sequence. Correct sequencing allows for a biomechanically fluid motion that contributes more power, explosiveness and efficiency while reducing workload and risk of injury. Abrupt gains or losses from one segment to the next can be indicative of potential problem areas or specific injury risks. Refined Conventional Motion: Hand Speeds The graph below represents subject hand speed during the trial from stance to finish. The red line represents the hand speed towards or away from the target (X-Axis). The green line represents hand speed laterally across the body (Y-Axis). The blue line represents hand speed up or down (Z-Axis).

The yellow line represents overall hand speed and is calculated based on all three vectors (X-, Y-, and Z-Axes) Overall Hand Speed Efficiency: 58.3% Direction Max (MPH) Min (MPH) At Delivery (MPH) Res. At Delivery (%) X Direction 60.28 -18.73 47.38 97.2 Y Direction 13.14 -21.76 -10.56 -21.7 Z Direction 22.65 -31.18 -4.32 -8.9 Resultant 62.04 0.06 48.73 n/a In the table above: · X Direction defines movement toward and away from the target. Positive values indicate hand speed toward the target. Negative values indicate hand speed away from the target. · Y Direction defines movement toward and away from the body laterally. Positive values indicate lateral hand speed away from the body. Negative values indicate lateral hand speed toward the body. · Z Direction defines movement up and down. Positive values indicate hand speed upwards. Negative values indicated hand speed downwards. Overall hand speed efficiency is an indicator of both accuracy and biomechanical efficiency. The higher the score the more likely any given pitch will be delivered to the target. Higher scores also predict less fatigue and less injury risk.

The subjects overall hand speed efficiency of 58.3%, using the Refined Conventional Motion, places him at risk for fatigue yet lowers the risk of injury as compared to the Unconventional Marshall Motion. Refined Conventional Motion: Body Posture at Toe Touch Toe touch is defined as the moment when the stride foot lands and weight has transferred in a straight line towards the target. Simultaneously the pitcher should initiate forward movement of the throwing arm and rotation of the pelvis and upper body. Posture at toe touch is vital if a pitcher is to be in a strong, athletic position where upper and lower body can work together to transfer energy efficiently. Overall Efficiency of Body Posture At Toe Touch: 37.8% Body Segment Subject Posture Ideal Posture Difference Pelvis Rotation 51.06 Open 45.00 Open 6.06 Open Spine Rotation 33.93 Closed 15.0 Closed 18.93 Closed Upper Body Rotation 17.01 Open 30.00 Open 12.99 Closed Head Rotation 75.66 Open 75.00 Open 0.66 Open Trail Foot Rotation 84.48 Open 35.00 Open 49.48 Open Lead Foot Rotation 93.90 Open 80.00 Open 13.90 Open Pelvis Forward-Backward Bend 2.52 Backward 2.00 Forward 4.52 Backward Spine Forward-Backward Bend 7.10 Backward 6.00 Forward 13.10 Backward Torso Forward-Backward Bend 7.66 Backward 8.00 Forward 15.66 Backward Head Forward-Backward Bend 2.67 Forward 10.00 Forward 7.33 Backward Trail Foot Dorsi-Plantar Flexion 66.68 Up 25.00 Up 41.68 Up Lead Foot Dorsi-Plantar Flexion 7.65 Up 0.00 Up 7.65 Up Pelvis Side Bend 2.82 Trail 3.00 Lead 5.82 Trail Spine Side Bend 7.84 Lead 5.00 Trail 12.84 Lead Torso Side Bend 4.09 Lead 2.00 Trail 6.09 Lead Head Side Bend 37.71 Lead 5.00 Trail 42.71 Lead Trail Foot Pronation-Supination 4.78 Outward 20.00 Inward 24.78 Outward Lead Foot Pronation-Supination 18.34 Outward 0.00 Outward 18.34 Outward (Note: All measurements in degrees; Data taken from frame 664)

Refined Conventional Motion: Body Posture At Ball Release Delivery or release point is defined as the instant in which the pitcher’s hand is furthest from the body in the direction of the target while the middle finger is still in contact with the ball. Every athlete must reach this point immediately at ball release. Overall Efficiency of Body Posture At Delivery: 28.1% Body Segment Subject Posture Ideal Posture Difference Pelvis Rotation 118.98 Open 90.00 Open 28.98 Open Spine Rotation 6.83 Closed 0.00 Open 6.83 Closed Upper Body Rotation 134.46 Open 90.00 Open 44.46 Open Head Rotation 134.09 Open 90.00 Open 44.09 Open Trail Foot Rotation 150.00 Open 80.00 Open 70.00 Open Lead Foot Rotation 93.38 Open 80.00 Open 13.38 Open Pelvis Forward-Backward Bend 21.48 Forward 10.00 Forward 11.48 Forward Spine Forward-Backward Bend 20.31 Forward 15.00 Forward 5.31 Forward Torso Forward-Backward Bend 40.73 Forward 25.00 Forward 15.73 Forward Head Forward-Backward Bend 17.18 Forward 2.00 Forward 15.18 Forward Trail Foot Dorsi-Plantar Flexion 57.13 Upward 85.00 Upward 27.87 Down Lead Foot Dorsi-Plantar Flexion 10.48 Upward 0.00 Upward 10.48 Upward Pelvis Side Bend 4.32 Trail 0.00 Trail 4.32 Trail Spine Side Bend 47.97 Lead 10.00 Trail 57.97 Lead Torso Side Bend 41.91 Lead 10.00 Trail 51.91 Lead Head Side Bend 24.37 Lead 0.00 Trail 24.37 Lead Trail Foot Pronation-Supination 4.61 Outward 7.00 Inward 11.61 Outward Lead Foot Pronation-Supination 4.55 Inward 0.00 Outward 4.55 Inward (Note: All measurements in degrees; Data taken from frame 706)

The following chart and robotic representation of the subject addresses the relative positions of shoulders vs. hips at ball release using the Refined Conventional Motion. System-generated robotic representation of the subject at ball release while, pitching using the Refined Conventional Motion. Conclusions & Outcomes Within a reasonable degree of scientific probability, the subject’s Unconventional Marshall Motion pitching technique was contributing to an acute overuse syndrome of the anterior left shoulder. When using the Refined Conventional Motion it was determined that the subject’s point of release was more consistent as well as his ability to throw the ball to spots accurately without pain in the anterior left shoulder capsule. The subject, after 3 days of training with the Refined Conventional Motion, was adjusting to his new pitching style. He was pain free and pitching at 100% effort, although feeling that he is only applying 85% of his effort. During the Refined Conventional Motion assessment, the motion direction of player’s center of gravity is consistent with the direction of ball flight, so it has an initial velocity before release. The results of strength assessments (both under static and dynamic conditions) cannot be directly compared to others results because the unconventional measurements procedure was applied.

Overall hand speed efficiency is an indicator of both accuracy and biomechanical efficiency. The higher the score the more likely any given pitch will be delivered to the target. Higher scores also predict less fatigue and less injury risk. The subjects overall hand speed efficiency of 25.4%, using the Unconventional Marshall Motion, places him at risk for both substantial fatigue and injury and predicts that he will have difficulty in throwing strikes with this delivery. When tested using the Refined Conventional Motion, the hand speed efficiencies were 58.3%, which is a considerable improvement from the Marshall Pitching Motion, yet will require a specific training regimen to minimize fatigue. Recommendations From a biomechanical prospective, to minimize shoulder stress in this subject’s pitching technique, it was recommended that he strive to relax his shoulder and utilize better control of trunk torque in the delivery of forces from the ground through the hand. He should delay ball release somewhat until his torso is in a more forward flexed posture and the upper arm segment is oriented more towards a parallel ground position. This will shift the stress point away from the anterior shoulder capsule.

The additional body stretch and torque will eventually translate to higher kinetic energy and faster ball delivery. It was stressed that changing his pitching style from the Unconventional Motion to a more revised Conventional Motion will adversely effect his accuracy and ball delivery ability until he re-adjusts his body coordination. It will be necessary for him to work on total body flexibility in order to achieve the new desired ball release position. Discussion The subject’s basic form is good in demonstrating both motions, but there is room for improvement in all aspects of his delivery. He is noted to have a pre-mature braking action of forward momentum causing him to release the ball in an upright posture that places the burden of shoulder capsule stress in the anterior compartment. This release posture was verified by examining the relatively close positioning of shoulders vs. hips and left shoulder vs. center of gravity. Additionally, using the glove-side arm to generate downward planar tilt to the shoulder line before torso rotation occurs appears to be a significant solution both in theory and in practice. Narrowing the rotational axis of shoulder/torso rotation as viewed from overhead provides a more linear Z vector. In theory, this could minimize the impact of destructive centrifugal forces.

Although there is some centrifugal force generated it appears likely that an athlete can control this with a more vertical forearm through release, initiated in part by action of the pronator teres and pronator quadratus. Many researchers who have investigated an overhand throw have indicated that muscle strength is a very important factor influencing throwing velocity [Pauwels 1978, Pedegana et al.1982, Amin et al.1985, Pawlowski and Perrin 1989, Renne et al.1990, Wooden et al.1992, Bartlet et al.1993, Eliasz 1993, Marczinka 1993]. In this work statistical analysis has shown that the muscle strength of trunk flexors is one of the most significant velocity determinants in analyzed throws (this variable is in all presented equations). Abdominal muscles (rectus abdominis, external and internal oblique muscles) serve as the primary trunk flexors. These muscles, acting together, are involved in forward bending but trunk rotation is caused by one-side shortening action of external and internal oblique muscles. Both types of motions can be observed during throwing, before release [Atwater 1980, Joris et al.1985, Eliasz 1993, Marczinka 1993]. The investigation has some practical applications.

There are two significant possibilities to improve throwing velocity, likely in all pitching techniques: (1) by developing strength of specific abdominal muscles, and (2) by improving speed of external and internal rotation at shoulder joint. [Joris et al.1985, Eliasz 1993]. It also appears that using the glove side arm to keep the front shoulder closed by adding a linear/angular refinement to the conventional pitching motion can reduce stress on the anterior throwing shoulder. These statements need further practical verification in the training process. Modern technological application of biomechanical principles can be an extremely useful problem-solving tool for sports medicine professionals. The clinician must be prepared to make judgments based on objective data when addressing the issue of returning the injured athlete to his or her sport. Often adjustments can be made in athletic technique to de-stress the injured body part, either on a temporary or permanent basis. In the case presented here, permanent change was necessary to allow this athlete to fully return to his sport and pursue his dream. Discussion With The Subject: Dissecting Problematic Unconventional Marshall Motion Teaching Cues Because of the controversial nature of the pitching motion Dr. Marshall has devised it was interesting to compare specific teaching cues he utilizes with the objectively measured results they produced in the subject’s technique. Marshall Instructional Cue: Point the glove arm straight at home plate.

The shoulder line and torso, as found using the JZZ system, is open 30-45º to the driveline beginning at toe touch, minimizing the total available pelvis and torso rotation. As demonstrated this leads to loss of hand speed and contributes substantially to release inconsistency. With this technique premature release of the leading side opens the shoulders very early and initiates complete rotational movement of the shoulders and takes away from angular rotation of the shoulders within the linear plane to the target. Marshall Instructional Cue:Walk forward off the mound. At toe touch the pelvic line, as taught by Dr. Marshall and as demonstrated by the subject, is open at stride 30-45º to the driveline, robbing power and minimizing total rotation before release. To compensate for this Dr. Marshall teaches a ‘drop stride’ for specific pitches. It was observed that with this technique the subject’s center of mass deflects laterally sideways. Biomechanically this was shown to be very inefficient and very inconsistent. It was observed that the drop step regains degrees of pelvic rotation, yet at release the torso still has not made up the difference and the arm lags behind leading to a disconnected linear-rotational-linear kinematic sequence. Marshall Instructional Cue: Rotate the hips; drive them through and then push off the stride foot. It was observed and measured that this cue disrupts the subject’s timing and disconnects kinematic sequencing. This kinetic disconnect, where the body rotates too fast, too soon, measurably diminishes hand speeds and resultant ball velocities.

The throwing arm and shoulder is also noted to lag far behind torso rotation and demonstrates great likelihood of causing a serious anterior shoulder problem. For an athlete with long levers like the study subject this is particularly problematic. Marshall Instructional Cue: Punch the throwing hand at the target. It was observed that this technique disconnects the kinetic chain, resulting in hand-first movement instead of arm-first movement. It was also observed and documented that when the hand leads this severely limits hand speed and resultant velocity. Marshall Instructional Cue: Force couple the glove and throwing hands and lean back at release. It was observed that the subject’s lead shoulder opens very early in the kinematic sequence, resulting in part from premature backward movement of the glove arm. This action of the glove arm and glove-side torso is observed to contribute significant stress to the anterior throwing arm shoulder. It was also observed that this simultaneously exaggerates torso tilt, displacing the subject’s center of gravity laterally, and also contributes to pre-mature braking of forward movement.

The torsional bending observed in this technique significantly displaces the head as a counterbalance and places significant stress on the neck and lower back. Marshall Instructional Cue: Driveline for the ball just above the ear. This teaching cue was demonstrated to be inaccurate in part because of the significant upward force applied to the ball hand in the Z-axis. For the forearm to approach vertical at ball release (highly desirable for spinning the ball in innovative ways), the minimum driveline is well above the head. If the body rotates far enough, as Dr. Marshall describes, with the forearm driving vertical (the upper arm then must be close to horizontal with very minimal torso tilt) the resultant force is simply a driving forearm arc. This technique and driveline is not linear as described by Dr. Marshall.

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