LOWER BODY CONTRIBUTIONS TO PELVIS ENERGY FLOW AND PITCH VELOCITY IN COLLEGIATE BASEBALL PLAYERS

The aims of this study were to examine the generation, absorption, and transfer of energy through the pelvis at the drive hip, stride hip, and lumbosacral joints and to determine predictors of ball speed during baseball pitching. Motion capture and ground reaction force (GRF) data from 20 collegiate pitchers were analysed using energy flow and LASSO regression analyses. Energy was transferred from the drive leg to the pelvis during the stride phase while energy was transferred from the pelvis to the stride leg and trunk during arm-cocking. Drive leg GRF, impulse, and stride hip generation contribute to pitch velocity

PELVIS ENERGY FLOW AND GROUND REACTION FORCE PREDICTORS OF ELBOW TORQUE IN HIGH SCHOOL AND COLLEGIATE BASEBALL PITCHERS

High joint forces and torques are associated with injury risk in baseball pitching. Energy flow (EF) analyses have provided valuable information on how segment and joint powers influence the pitching motion but have not been used to investigate EF influence on elbow torque. The purpose of this study was to determine the relationship of pelvis EF and ground reaction force (GRF) with elbow valgus torque in a sample of high school and collegiate baseball pitchers using regularized regression and statistical parametric mapping. A set of 14 GRF and EF variables were found to be predictors of maximum elbow valgus torque. Both groups differed in pitch velocity and elbow torque but exhibited similar patterns of energy generation and transfer at the stride hip and L5S1 joints. These findings could translate to lower body strategies to reduce the injury risk of high school and collegiate pitchers

RELATIONSHIP OF SEGMENTAL ENERGY FLOW AND ELBOW VALGUS LOADING DURING BASEBALL PITCHING

The purpose of this study was to examine the relationship of intersegmental power with elbow valgus load during pitching in adult baseball players. Kinematic and kinetic data from 24 male baseball pitchers (college n = 8; professional n = 16) were analysed using marker-based motion analysis and multiple linear regression. The segmental powers delivered by trunk rotation and shoulder internal rotation torques in the arm cocking phase accounted for 72% of the variance in peak elbow valgus torque (r = .848, p \u3c 0.01). Furthermore, the power supplied by trunk rotation was the only significant predictor of ball speed (r = .840, p \u3c 0.01). This segmental power analysis reinforces evidence that the rotational torques at the trunk and shoulder have the greatest effect on the development of elbow valgus load

THE EFFECTS OF COMPRESSION TIGHTS ON DYNAMIC KNEE MOTION DURING A DROP VERTICAL JUMP IN FEMALE COLLEGE ATHLETES

The purpose of this study is to evaluate the ability of compression tights to influence knee motion during a drop vertical jump (DVJ) in healthy college-aged female athletes. 23 athletes participating in jumping sports (volleyball, basketball, and soccer) were tested. A standard Helen-Hayes 29-marker set was applied to the subjects and recorded using 8 visible-red cameras and 2 force plates. Average hip internal rotation was reduced by 1.9° (p= 0.005), hip abduction range of motion was 2.4° less (p= 0.002), hip abduction angle at initial contact was reduced by 2.7° (p= 0.018), and knee valgus angle at initial contact was also reduced by 1.7° (p= 0.029). These changes support the idea that compression tights may aid in injury prevention and rehabilitation. In the future EMG could be use to identify differences in muscle activation patterns

ENERGY FLOW AND IMPULSE PREDICTORS OF BAT SPEED DURING BASEBALL TEE BATTING USING THE LEAST ABSOLUTE SHRINKAGE AND SELECTION OPERATOR (LASSO) REGRESSION

The purposes of this study were to examine how energy is generated, absorbed, and transferred through the pelvis during the baseball swing and to identify the best model of ground reaction force (GRF) and energy flow (EF) predictors of bat speed using a LASSO regression, which reduced the dataset to a model of four EF and two impulse variables that best predicts bat speed. The findings indicate that the mechanical energy flows from the trunk to the lead leg via the pelvis as these segments rotate during the swing. It is hoped that these findings will aid coaches and athletes in better understanding which elements of the swing movement are most closely related to bat speed. Thus, coaches may be able to develop and implement training strategies accordingly to improve bat speed and player performance

DIFFERENCES IN THE ENERGY FLOW, GROUND REACTION FORCE, AND IMPULSE DURING BASEBALL TEE BATTING BETWEEN HIGH SCHOOL AND COLLEGIATE BASEBALL PLAYERS

The purposes of this study were to examine the differences in the peak impulses and ground reaction forces (GRF) of the lead and back legs as well as how energy flows (energy absorption, generation, and transfer) in the back hip, front hip, and L5S1 joints during the baseball swing phases between high school and collegiate baseball players. The findings indicate that the mechanical energy flows down the chain from the L5S1 joint to the pelvis into the lead leg during the bat acceleration phase of the swing in both participant groups. It is hoped that these findings may help coaches and athletes understand which kinetic components of the swing improve bat speed. Thus, coaches may develop training strategies to improve bat speed and player performance

BALL SPEED PREDICTORS IN SLIDE ATTACKS IN FEMALE VOLLEYBALL PLAYERS

The purpose of this study was to investigate ball speed predictors of slide attacks and provide direct parameters for their proper execution. Healthy collegiate female volleyball players (n = 8) were recruited. After a warm-up, 3 successful slide attacks per participant and their ball speed were recorded using an 8-camera motion capture system and a radar gun. COM approach speed, maximum angular velocity of pelvis and torso rotation in the arm cocking phase, and maximum angular velocity of torso rotation, shoulder IR, and elbow extension in the arm acceleration phase were calculated for the trial with the fastest ball speed. The multiple stepwise regression was not statistically significant (p = .098). The findings indicate that peak torso rotation angular velocity in the arm cocking phase and peak shoulder IR and peak elbow extension angular velocities in the arm acceleration phase may be important contributors to the ball speed in slides

MULTI-SEGMENT CONTRIBUTIONS TO INDUCED BALL VELOCITY IN COLLEGIATE BASEBALL PITCHERS

The purpose of this study was to implement an induced acceleration analysis (IAA) to estimate the contributions of multi-segment motion to the forward velocity of the ball in collegiate baseball pitchers. Marker-based motion capture and ground reaction force data were collected from a sample of 17 pitchers throwing off an instrumented mound. Kinematic and kinetic data were extracted to drive the IAA model to calculate the muscular and non-muscular contributions to ball velocity. The shoulder joint torque and velocity-dependent torque collectively made up the largest contribution to the total induced velocity of the ball at 61% and 37%, respectively. The model underestimated ball speed by 16%, owing to limitations in distal segment definitions. Although this IAA showed that the proximal segments make a small, direct contribution to forward ball velocity, decomposition of the velocity-dependent torque could further clarify the extent to which the legs, pelvis, and trunk indirectly contributes to ball velocity

GROUND REACTION FORCES IN RUNNING SHOES WITH TWO TYPES OF CUSHIONING COLUMN SYSTEMS

The purpose of this investigation was to evaluate the effects of running shoes with two types of cushioning column systems on impact forces during running. Kinematic and ground reaction force data were collected from ten normal subjects wearing shoes with the following cushions: 4-column MPU elastomer (Shoe 1), 4-column thermoplastic polyester elastomer (Shoe 2), and 1-unit EVA foam (Shoe 3). Subjects exhibited significantly lower impact force (p =.02) and loading rate (p =.005) with shoe 2 (1.84 ± .24 BW; 45.6 ± 11.6 BW/s) compared to shoe 1 (1.94 ± .18 BW; 57.9 ± 12.1 BW/s). Both cushioning column shoes showed similar impact force characteristics to those of a topmodel running shoe (shoe 3). This study showed that even in similar shoe types, impact force and loading rate values could significantly vary with midsole cushion constructions

RELATIONSHIP BETWEEN GROUND REACTION FORCE AND THROWING ARM KINETICS IN HIGH SCHOOL AND COLLEGIATE BASEBALL PITCHERS

The purpose of this study was to examine the relationship of ground reaction force (GRF) of the drive and stride leg and kinetics of the throwing arm in high school and collegiate baseball pitchers. Several studies have examined the relationship between GRF and ball velocity, but no one has examined the effect of GRF on maximum shoulder rotation torque (MERT) and maximum elbow valgus torque (MEVT). Understanding this relationship will be important to both enhancing performance and avoiding injury. Data that were previously collected during a pitching evaluation were analyzed. Twenty-two high school pitchers and 13 collegiate pitchers had received a pitching evaluation. Multiple regression analysis was used to examine the relationships between variables. Only the drive leg medial force (β = .372, p = .015) and stride leg braking force (β = .401, p = .009) were significant predictors of MERT