Epidemiologic Comparison of Pitching Mechanics, Pitch Type, and Pitch Counts Among Healthy Pitchers at Various Levels of Youth Competition.

PURPOSE: To determine differences among healthy pitchers at various levels of competition regarding pitching history, pitching mechanics, and prevalence of breaking pitches. METHODS: Demographic, anthropometric, pitching history, and kinematic data were collected on healthy youth pitchers using dual orthogonal high-speed video analysis. Players were grouped by maturity level (9 to 12 [prepubescent], 13 to 15 [pubescent], 16 to 17 [mature], and 18 to 22 years [adult]). Groups were compared regarding pitch counts, pitching mechanics, and use of breaking pitches. Mechanics were assessed for favorable observational parameters (e.g., closed foot orientation at foot-strike) and measurable parameters at cocking, foot-strike, and ball release (e.g., knee flexion). RESULTS: Two hundred ninety-five pitchers were included. Sixty-three were 9 to 12, 130 were 13 to 15, 78 were 16 to 17, and 24 were 18 to 22 years of age. Older pitchers threw more pitches per game (41, 52, 69, and 50 by age group; P < .001), per season (766, 975, 1,079, and 881; P = .017), and per year (901, 1,343, 2,064, and 1,302; P < .001). They were more likely to pitch for multiple teams, for more than 9 months, in showcases, and in violation of pitch count recommendations. Older pitchers were more likely to maintain their hand on top of the ball, maintain closed shoulders at foot-strike, achieve hip and shoulder separation, and lead with their hips. Older pitchers achieved greater relative stride-length, greater knee flexion at front-foot contact, and increased lead hip flexion at ball release. Pitchers began throwing curveballs and sliders at 12.6 and 13.5 years, respectively. CONCLUSIONS: As pitchers age, they throw more pitches per game, per season, and per year and are more likely than younger pitchers to violate pitch count recommendations. Older pitchers tend to pitch with improved mechanics and velocity. The proportion of pitchers throwing breaking pitches increases with age, with the greatest increase occurring between ages 12 and 13. LEVEL OF EVIDENCE: Level II, cross-sectional study.

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

PURPOSE: To determine if shoulder and elbow kinematics, pitching velocity and accuracy, and pain change during a simulated baseball game in adolescent pitchers. METHODS: Adolescent male pitchers aged 13 to 16 years were included. Pitchers were excluded if they had undergone previous shoulder or elbow surgery, currently had a known shoulder or elbow injury, or were unable to complete the simulated game for any reason. Shoulder range of motion was assessed before and after the game. Velocity and accuracy were measured for every pitch, and every 15th pitch was videotaped from 2 orthogonal views in high definition at 240 Hz. Quantitative and qualitative mechanics were measured from these videos. Perceived fatigue and pain were assessed after each inning using a visual analog scale. Data were statistically analyzed using a repeated-measures analysis of variance. RESULTS: Twenty-eight elite adolescent pitchers were included. These pitchers, on average, were aged 14.6 ± 0.9 years (mean ± standard deviation), had been pitching for 6.3 ± 1.7 years, and threw 94 ± 58 pitches per week. Our experimental model functioned as expected in that pitchers became progressively more fatigued (0.3 ± 0.6 to 3.5 ± 2.1), had more pain (0.1 ± 0.4 to 1.6 ± 2.2), and pitched with a lower velocity (73 ± 5 mph to 71 ± 6 mph) as pitch number increased (P < .001, P = .001, and P < .001, respectively). Knee flexion at ball release progressively increased (49° ± 15° to 53° ± 15°) with pitch number (P = .008). Hip-to-shoulder separation significantly decreased as pitch number increased, from 90% ± 40% at pitch 15 to 40% ± 50% at pitch 90 (P < .001). Upper extremity kinematics remained unchanged (P > .271 in all cases, 91% power for elbow flexion at ball release). External rotation and total range of motion in the pitching shoulder significantly increased after pitching (P = .007 and P = .047, respectively). CONCLUSIONS: As pitchers progress through a simulated game, they throw lower-velocity pitches, become fatigued, and have more pain. Core and leg musculature becomes fatigued before upper extremity kinematics changes. CLINICAL RELEVANCE: On the basis of these results, there is the potential that core strengthening and leg strengthening may be valuable adjuncts to prevent upper extremity injury. Further studies specifically looking at this must be conducted.

Correlates With History of Injury in Youth and Adolescent Pitchers.

PURPOSE: To determine the factors within pitcher demographic characteristics, pitching history, and pitch kinematics, including velocity, that correlate with a history of pitching-related injury. METHODS: Demographic and kinematic data were collected on healthy youth and adolescent pitchers aged 9 to 22 years in preseason training during a single preseason using dual orthogonal high-speed video analysis. Pitchers who threw sidearm and those who had transitioned to another position were excluded. Players were asked whether they had ever had a pitching-related shoulder or elbow injury. Multivariate logistic regression analysis was performed on those variables that correlated with a history of injury. RESULTS: Four hundred twenty pitchers were included, of whom 31% had a history of a pitching-related injury. Participant height (P = .009, R(2) = 0.023), pitching for more than 1 team (P = .019, R(2) = 0.018), and pitch velocity (P = .006, R(2) = 0.194) served as independent correlates of injury status. A model constructed with these 3 variables could correctly predict 77% of injury histories. Within our cohort, the presence of a 10-inch increase in height was associated with an increase in a history of injury by 20% and a 10-mph increase in velocity was associated with an increase in the likelihood of a history of injury by 12%. Playing for more than 1 team increased the likelihood of a history of injury by 22%. CONCLUSIONS: Pitch velocity, pitcher height, and pitching for more than 1 team correlate with a history of shoulder and elbow injury. Current recommendations regarding breaking pitches may not prevent injury. Pitchers should be cautioned about pitching for more than 1 team. Taller pitchers and high-velocity pitchers may be at risk of injury.

Predictors of throwing velocity in youth and adolescent pitchers.

BACKGROUND: Shoulder and elbow injuries are a common cause of pain, dysfunction, and inability to play in overhead throwers. Pitch velocity plays an integral part in the etiology of these injuries; however, the demographic and biomechanical correlates with throwing velocity remain poorly understood. We hypothesized that pitchers with higher velocity would have shared demographic and kinematic characteristics. METHODS: Normal preseason youth and adolescent pitchers underwent dual-orthogonal high-speed video analysis while pitch velocity was collected with a radar gun. Demographic and pitching history data were also collected. Kinematic data and observational mechanics were recorded. Multivariate regression analysis was performed. RESULTS: A total of 420 pitchers were included, with a mean pitching velocity of 64 ± 10 mph. After multivariate logistic regression analysis, the most important correlates with pitch velocity were age (P < .001; R(2) = 0.658), height (P < .001; R(2) = 0.076), separation of the hips and shoulders (P < .001; R(2) = 0.027), and stride length (P < .001; R(2) = 0.016); in combination, these 4 variables explained 78% of the variance in pitch velocity. Each year of age was associated with a mean 1.5 mph increase in velocity; each inch in height, with 1.2 mph; separation of the hips and shoulders, with 2.6 mph; and a 10% increase in stride length, with 1.9 mph. CONCLUSION: Pitch velocity is most strongly correlated with age, height, separation of the hips and shoulders, and stride length.

Design of a synthetic simulator for pediatric lumbar spine pathologies.

OBJECT: Simulation has become an important tool in neurosurgical education as part of the complex process of improving residents' technical expertise while preserving patient safety. Although different simulators have already been designed for a variety of neurosurgical procedures, spine simulators are still in their infancy and, at present, there is no available simulator for lumbar spine pathologies in pediatric neurosurgery. In this paper the authors describe the peculiarities and challenges involved in developing a synthetic simulator for pediatric lumbar spine pathologies, including tethered spinal cord syndrome and open neural tube defects. METHODS: The Department of Neurosurgery of the University of Illinois at Peoria, in a joint program with the Mechanical Engineering Department of Bradley University, designed and developed a general synthetic model for simulating pediatric neurosurgical interventions on the lumbar spine. The model was designed to be composed of several sequential layers, so that each layer might closely mimic the tensile properties of the natural tissues under simulation. Additionally, a system for pressure monitoring was developed to enable precise measurements of the degree of manipulation of the spinal cord. RESULTS: The designed prototype successfully simulated several scenarios commonly found in pediatric neurosurgery, such as tethered spinal cord, retethered spinal cord, and fatty terminal filum, as well as meningocele, myelomeningocele, and lipomyelomeningocele. Additionally, the formulated grading system was able to account for several variables involved in the qualitative evaluation of the technical performance during the training sessions and, in association with an expert qualitative analysis of the recorded sessions, proved to be a useful feedback tool for the trainees. CONCLUSIONS: Designing and building a synthetic simulator for pediatric lumbar spine pathologies poses a wide variety of unique challenges. According to the authors' experience, a modular system composed of separable layers that can be independently replaced significantly enhances the applicability of such a model, enabling its individualization to distinctive but interrelated pathologies. Moreover, the design of a system for pressure monitoring (as well as a general score that may be able to account for the overall technical quality of the trainee's performance) may further enhance the educational applications of a simulator of this kind so that it can be further incorporated into the neurosurgical residency curriculum for training and evaluation purposes.