The Development of a Novel Pitching Assessment Tool

Posture based ergonomic assessment tools are widely used to evaluate posture and injury risk for many workplace/occupational tasks. To date, there is no validated equivalent that can be used to assess the posture of a pitcher during baseball pitching. Therefore, the purpose of this study was to develop an inexpensive tool which can allow for the rapid assessment of a pitcher’s posture at lead foot strike, and establish the inter- and intra- rater reliability of the tool. For this study, 11 participants threw 30 pitches (15 fastballs, 15 curveballs) off an indoor pitching. Full body 3D kinematics were measured using reflective markers attached to anatomical landmarks and rigid bodies attached to body segments using a 10-camera Vicon Motion Capture system along with two high-speed video cameras (rear and side view) to record each pitch during the experimental trials. The kinematic data was analyzed, after which the highest velocity fastball of each of the 11 pitchers was selected for further analysis. A Pitching Mechanics Tool was designed to evaluate 16 different parameters at lead foot strike. Each of the 16 parameters had posture ranges or categories established based on scientific literature. Six evaluators with at least five years of experience working with adult pitchers completed the Pitching Mechanics Tool. Findings showed moderate to good levels of repeatability across multiple sessions as well as across multiple evaluators. Additionally, PMT results suggested that 2D qualitative analysis is a viable alternative to 3D motion capture

The relationship between angular momentum of the lower trunk and shoulder joint forces in overarm throwing athletes

Overarm throwing athletes utilize the kinetic chain, which allows forces generated by the lower body to be transmitted to the throwing arm in a proximal-to-distal sequence. Efficient force transmission from the lower body to the throwing arm can improve performance and reduce risk for injury. The purpose of this thesis was to explore the relationship between the lower trunk (pelvis) maximum angular momentum and the joint resultant forces at the shoulder during the overarm throwing motion of baseball athletes. I hypothesized that there would be a negative correlation between the maximum angular momentum about the superior-inferior axis of the lower trunk during the arm cocking phase and the throwing shoulder joint anterior shear force at ball release, and that there would be a negative correlation between the maximum angular momentum about the superior-inferior axis of the lower trunk during the arm cocking phase and the throwing shoulder joint compressive force at ball release. Two high-speed video cameras were used to record twenty-four competitive male baseball players executing an overarm throw. The videos were digitized, and 3D landmark coordinates were obtained using the Direct Linear Transformation procedure. Lower trunk angular momentum, shoulder joint compressive force, and shoulder joint anterior shear force were calculated from the 3D landmark coordinates and anthropometric data. Bivariate correlations were computed to determine if an association existed between maximum lower trunk angular momentum and shoulder joint anterior shear force at release or shoulder joint compressive force at release. There was no association between lower trunk maximum angular momentum and shoulder joint anterior shear force (r = 0.149, p = 0.244). There was also no association between lower trunk maximum angular momentum and shoulder joint compressive force (r = 0.222, p = 0.149). The lack of association between the lower trunk maximum angular momentum and shoulder joint forces may indicate that this relationship is not determinative of overarm throwing technique. An alternative explanation is that the subjects exhibited inefficient mechanics and an improper timing sequence of the kinetic chain. Future work should investigate the sequencing of force transmission between the lower body and upper body

Stride Leg Ground Reaction Forces Pre- and Post-Fatigue in Collegiate Baseball Pitchers

Context: Baseball pitching requires the coordination of the lower and upper extremities to effectively generate and transfer force to the ball. High-velocity pitchers have been found to have significantly greater stride leg force generation than low-velocity pitchers. The influence of stride leg fatigue on pitching has yet to be investigated. Objective: The purpose of this study was to examine the effect of stride leg fatigue on peak vertical ground reaction forces (vGRFs) and hand velocity. Design: Pretest-posttest. Setting: Biomechanics laboratory. Patients or Other Participants: A convenience sample of 11 collegiate baseball pitchers (19.27 ± 0.64 years old; 85.88 ± 12.16 kg; 1.84 ± 0.07 m; eight right-handed, three left-handed) volunteered. To be included, participants needed to be listed as a pitcher on a collegiate baseball roster without reported injuries to the upper or lower extremity that resulted in decreased training volume during the fall baseball season. Interventions: Simultaneous three-dimensional kinematic (200 Hz; Vicon Motion System Ltd., Oxford,UK) and kinetic data (1,000 Hz, Kistler Inc., Amherst, NY, USA) were collected. Participants utilized a self-selected, competition-style warm-up. Retro-reflective markers were placed on bony landmarks of the stride leg, trunk, and throwing arm. Participants threw maximal effort fastballs into a net placed 5.0 meters from the portable pitching mound’s rubber. Participants were positioned so that the stride leg foot landed on the force platform. After 10 rested-state pitches, participants performed a fatigue protocol of stride leg Bulgarian split squats at 60 beats/minute for maximum repetitions. One-minute rest was given between each of the four sets. Following the fatigue protocol, participants threw 10 fatigued-state maximal effort pitches. Main Outcome Measures: Outcome measures included peak vGRFs of the stride leg and hand velocity at release. The means of valid trials (minimum of seven) were used for analyses. Peak vGRFs were reported as body weight [BW=GRF/(kg·9.81m/s2)]. One-tailed, paired t-tests (α = 0.05) were utilized to test for statistical significance between rested and fatigued conditions and a Pearson product-moment correlation were used to examine the relationship between vGRFs and hand velocity. Statistics were computed in SPSS. Results: Participants completed 81.36 ± 21.94 total Bulgarian split squat repetitions and reported an RPE score of 7.82 ± 1.60. Paired t-tests revealed significant decrease (p = 0.005) between peak Fz1 vGRF values in rested-state (1.57 ± 0.49 BW) compared to fatigued-state (1.31 ± 0.62 BW). Hand velocity in the rested-state (23.32 ± 1.60 m/s) was significantly (p=0.004) higher than fatigued-state (22.61 ± 1.55 m/s), but not functionally relevant. Peak vGRF and hand velocity at release were not significantly correlated in either condition (rested-state Fz1: r = 0.162, p = 0.318; Fz2: r =.151, p = 0.329; fatigued-state Fz1: r = 0.228, p = 0.250; Fz2: r = 0.277, p = 0.410). Conclusions: Peak vGRFs Fz1 and hand velocity decreased when the stride leg fatigued to a level of statistical significance. Due to the small sample size, the variable does warrant future investigation. Increased understanding of the influence of the stride leg upon pitching endurance and performance could influence rehabilitation and training programs

Comparison of lower body segment alignment of elite level hockey players to age-matched non-hockey players

Master's Project (M.A.) University of Alaska Fairbanks, 2015Lower body overuse and insidious onset injuries are thought to have an underlying biomechanical component which may be predisposing to injury. The purpose of this study was to compare lower body biomechanical characteristics for elite hockey players to matched controls. I hypothesize that elite hockey players have a greater degree of anterior pelvic tilt, greater varus knee angle, a higher foot arch and feet held in parallel more during gait than a matched non-skating population. Measures were taken of elite level, college aged, male hockey players and compared to cross country runners (ten subjects in each group) who served as controls for trunk angle, pelvic tilt angle, knee alignment, (varus/valgus angle), foot angle, arch index (arch height), hip, center of range of motion, hip external rotation, hip internal rotation, hip total range of motion (ROM), knee transverse plane ROM, and step width. The results obtained support the hypothesis for anterior pelvic tilt and foot angle during gait. Although knee angle was in the expected varus direction it was not significant and no differences were observed in the foot arch between the groups. All other measurements not directly related to the hypothesis were not significantly different with the exception of mean step width. The obtained results are important as recent literature describes a lower body posture of medial collapse into "dynamic valgus" as being predisposing to injury. Results show, on the spectrum from lower body varus to lower body valgus, hockey players are on the varus side of the spectrum in all attributes except arch height, which was similar in both populations. Since lower body alignment is thought to be coupled, this inconsistency appears contrary to the "medial collapse into dynamic valgus" model and may explain why foot orthotics and athletic shoes used as an injury intervention often fail

Biomechanics of the lower extremity during a windmill style fast-pitch

The windmill style fastpitch involves an array of motor skills requiring sequential coordination of the upper and lower extremities. Characteristic of the motion is a powerful drive and rapid transfer offeree on to the striding lower extremity. This may result in a substantial breaking force over a short period of time. The purpose of this study was to determine the kinematic responses and magnitude of ground reaction forces (GRF) created by the stride leg in selected windmill pitches. Five female intercollegiate fastpitch softball pitchers (age: 22.6 yrs, body mass: 69.0 kg) performed 5 pitches of the fastball (FB), changeup (CH), dropball (DB), curveball (CB) and riseball (RB). Simultaneous recordings of video (60hz) and GRF (1000 hz) were obtained and synchronized for each trial. Kinematic variables evaluated included stride length, ball velocity, joint angle at contact (JAC), maximum angle (MAX), time to maximum angle (TMAX), minimum angle (MIN) and time to minimum angle (TMIN). Primary kinetic variables evaluated were first peak force (F1), second peak force (F2) and maximum brake force (Fb). Single factor ANOVAs revealed significant kinematic differences (p \u3c 0.05) between pitches for MAX and MIN for hip, knee and ankle, as well as, differences in JAC for hip and knee. Stride lengths of the participants in this study indicate that different strategies were used in the delivery of the various pitches. Stride lengths were longest for the riseball and shortest for the change-up. In general, the pitchers adopted a style characterized by extended hip and knee joint and plantarflexed ankle joint. Comparison of stride lengths to total body range of motion at contact indicated that longer stride lengths are associated with a less upright position of the body. In general the fastball, curveball and riseball had longer stride lengths and greater total body range of motion. In contrast, the body assumes a more upright position in pitches with a shorter stride length, such as the change-up and dropball. The results also indicated trends of slower ball velocities with a more upright body position. Peak vertical forces during pitching are higher than those reported in walking and low impact aerobics. In addition, peak vertical forces experienced during pitching appear to be similar to those reported in distance running and high impact aerobics. However, peak forces are lower than those reported in jump/landing skills in basketball and volleyball. Maximum braking forces of pitching are higher than those reported in running and walking. In addition, the braking forces produced in pitching are higher than common movements performed in basketball, with the exception of landing after a layup shot. The riseball had the highest braking force followed by the fastball, whereas the lowest braking force occured in the change-up. The findings indicate a trend that pitches with the highest F1 values are accompanied by high maximum braking forces and vice versa for pitchers with the lowest F1 values. These findings indicate trends that the pitches with the highest F1 values are accompanied by high maximum braking forces and vice versa for pitchers with the lowest F1 values

Analysis of the backpack loading efects on the human gait

Gait is a simple activity of daily life and one of the main abilities of the human being. Often during leisure, labour and sports activities, loads are carried over (e.g. backpack) during gait. These circumstantial loads can generate instability and increase biomechanicalstress over the human tissues and systems, especially on the locomotor, balance and postural regulation systems. According to Wearing (2006), subjects that carry a transitory or intermittent load will be able to find relatively efficient solutions to compensate its effects.info:eu-repo/semantics/publishedVersio

Effects of Trunk Movement on Pitching Biomechanics and Performance in High School Baseball Pitchers

Pitching-related upper extremity injuries affect a large number of high school baseball pitchers. Therefore, it is important to develop an intervention strategy to prevent these injuries. One of the suggested risk factors for the pitching-related upper extremity injuries is an improper technique that results in an added stress on the shoulder and elbow joints. Therefore, the purpose of the study was to examine the effects of selected pitching technique parameters on joint loading, performance, and overall quality of pitching technique, by focusing on the observable technical errors of the trunk. The specific technical errors examined were: 1) open shoulder, 2) backward lean at stride foot contact, 3) lateral lean at stride foot contact, 4) lateral lean at maximal shoulder external rotation (LLMER), and 5) inadequate forward trunk tilt at ball release. The pitching biomechanics of 73 high school baseball pitchers were captured using a motion capture system, two high speed cameras, and a radar gun. The presence of each error was determined by the raters who reviewed the pitching trial videos. The joint loading, performance, and quality of pitching technique were compared between the pitchers who did and did not demonstrate each error. We observed that the pitchers with LLMER demonstrated a higher ball speed but also experienced an increased joint loading at the shoulder and elbow joints. This suggests that LLMER is a strategy that pitchers take in order to achieve a higher ball speed at an expense of increased joint loading. Additionally, there was a trend that an inadequate (45°) forward trunk tilt (FTT) angle at the ball release may influence the joint loading that are linked to injuries. These technical errors should be avoided considering the negative consequences of injuries. Since these technical parameters can be observed using video cameras, screening of pitching technique can be used to identify pitchers with these technical errors. Possible strategies to modify LLMER and FTT angle at ball release were also identified. Using these strategies, it may be possible to correct the technical errors and thereby prevent the pitching-related upper extremity injuries.Doctor of Philosoph

Test-Re-test Reliability of Sahrmann Lower Abdominal Core Stability Test for DII Baseball Athletes

Context: Baseball athletes need to maintain a strong core for functional activities. The core not only transfers the energy from the hips to the throwing arm, but maintains stability and can decrease injury rates. There are several tests represented in the literature to measure core stability, but none have been advocated to use for baseball. Objective: The purpose of this study was to determine the reliability of the Sahrmann lower abdominal core stability in baseball. Design: The study was conducted as a prospective test re-test design. Setting: The testing took place at one location and only one clinician administered the testing. Data collection took place at the athletic facilities on the campus of a Division II Mid-Atlantic University. Patients and Other Participants: A totally of 30 participants from a D-II baseball program will be used for this study. The subjects were 19.73+/-1.41 year\u27s old, 83.93+/-6.94 kg in weight and 180.68+/-5.06 cm in height. All participants volunteered for the study and were current players encompassing a variety of positions, and were injury free within 6 months. Interventions: The participants were asked to complete as much of the Sahrmann lower abdominal core stability test correctly. There was no warm up prior to testing. The testing protocol was demonstrated and there was a training period consisting of 2 sub-max trials. The data was collected over a two week period. Main Outcomes Measures: The dependent variable was the result of the Sahrmann lower abdominal core stability test. Results: Overall, the ICC score for the Sahrmann lower abdominal test was ICC33,1=0.649 (95% confidence interval =.257 to .832, P=.003). This ICC value reflects moderate reliability for the Sahrmann lower abdominal test. The standard error of the measurement (SEM) value that is reported is SEM=0.302, which would be described as low. Conclusions: Until further studies are conducted it is difficult to determine whether Sahrmann lower abdominal core test is a valid core stability test because there is no core stability gold standard. Determining a gold standard to measure core specifically may be difficult. There are multiple concepts and philosophies about core, stability, strength, endurance, and power. The Sahrmann core stability test has moderate reliability when used with Division II baseball athletes at one institution

Next generation cricket bowling machine

Cricket is a traditional team sport played in over 100 countries around the world. Unlike many mainstream sports, cricket has seen little research and development within the equipment used to play the game. Ball launching machines have been used as a training aid in a number of sports including cricket, however, as with the playing equipment used, these too have seen little development. Current cricket bowling machines enable players to train at a high intensity producing repeatable deliveries for batsmen to hone their skills. A need has been established by the coaching staff of the England and Wales Cricket Board (ECB) for a cricket training system that provides batsmen with a match realistic environment in which to train. Existing cricket bowling machines do not offer batsmen pre-release visual information that they would receive in a match situation and the most popular models release moulded, dimpled balls that do not replicate the performance of cricket balls.... cont'd

Hip Flexibility Associated with Pitching Technical Errors

Pitching technical errors have been linked to increased upper extremity injurious forces in baseball pitchers. Hip flexibility plays a key role in dynamic movement and may affect the ability of a pitcher to properly distribute force throughout a pitch. This could lead to certain technical errors and predispose a pitcher to injury. The purpose of this study was to determine if hip extension, internal rotation and external rotation range of motion is associated with baseball pitching technical errors in adolescent baseball pitchers. Each participant had their hip range of motion measured then pitched 15 fastballs while being filmed from the frontal and sagittal views. The videos were graded for technical errors. Point biserial Pearson r correlations were run between stance leg extension, bilateral hip internal rotation, bilateral hip external rotation and each technical error. No significant correlations were found. While it is still believed that hip flexibility plays a role in force transfer throughout the pitching sequence, this study did not support passive hip range of motion being correlated with technical errors. However, the majority of adolescent males did have restricted hip range of motion values compared to normative values. Active hip range of motion may be a more suitable measurement to use given the dynamic nature of baseball of pitching.Master of Art