Effect of three different between-inning recovery methods on baseball pitching performance

A decrease in blood hydrogen ions (H) may allow for the recovery of a muscle, which should allow for greater performance in subsequent activity. The purpose of this study was to determine which of 3 forms of recovery were the most effective after an inning of pitching in baseball. Three different measurements were used to determine which recovery method was most effective; the difference in blood lactate (BLa) levels was used as a biological measurement, average pitching speed was the physiological measurement, and the psychological measurement was done on how the pitchers perceived their pitching and recovery. The recovery methods that were used were passive recovery (PR), active recovery (AR), and electromuscular stimulation (EMS). Seven college men aged 21 (±2 years) who were National Collegiate Athletic Association Division II college baseball pitchers were assessed during game play simulations. Blood lactate levels decreased significantly from the premeasurement to the postmeasurement with the EMS recovery method (p < 0.0005); however, BLa did not change for PR (p = 0.017) or AR (p = 0.134). Perceived recovery was also found to be best in the EMS and PR conditions. These findings suggest that EMS is an effective recovery method between innings of pitching.     

Lower-extremity ground reaction forces in collegiate baseball pitchers

The purpose of this study was to investigate ground reaction forces (GRF) in collegiate baseball pitchers and their relationship to pitching mechanics. Fourteen healthy collegiate baseball pitchers participated in this study. High-speed video and force plate data were collected for fastballs from each pitcher. The average ball speed was 35 ± 3 m/sec (78 ± 7 mph). Peak GRFs of 245 ± 20% body weight (BW) were generated in an anterior or braking direction to control descent. Horizontal GRFs tended to occur in a laterally directed fashion, reaching a peak of 45 ± 63% BW. The maximum vertical GRF averaged 202 ± 43% BW approximately 45 milliseconds after stride foot contact. A correlation between braking force and ball velocity was evident. Because of the downward inclination and rotation of the pitching motion, in addition to volume, shear forces may occur in the musculoskeletal tissues of the stride limb leading to many of the lower-extremity injuries seen in this athletic population.     

Relationship of biomechanical factors to baseball pitching velocity: within pitcher variation

To reach the level of elite, most baseball pitchers need to consistently produce high ball velocity but avoid high joint loads at the shoulder and elbow that may lead to injury. This study examined the relationship between fastball velocity and variations in throwing mechanics within 19 baseball pitchers who were analyzed via 3-D high-speed motion analysis. Inclusion in the study required each one to demonstrate a variation in velocity of at least 1.8 m/s (range 1.8-3.5 m/s) during 6 to 10 fastball pitch trials. Three mixed model analyses were performed to assess the independent effects of 7 kinetic, 11 temporal, and 12 kinematic parameters on pitched ball velocity. Results indicated that elbow flexion torque, shoulder proximal force, and elbow proximal force were the only three kinetic parameters significantly associated with increased ball velocity. Two temporal parameters (increased time to max shoulder horizontal adduction and decreased time to max shoulder internal rotation) and three kinematic parameters (decreased shoulder horizontal adduction at foot contact, decreased shoulder abduction during acceleration, and increased trunk tilt forward at release) were significantly related to increased ball velocity. These results point to variations in an individual's throwing mechanics that relate to pitched ball velocity, and also suggest that pitchers should focus on consistent mechanics to produce consistently high fastball velocities. In addition, pitchers should strengthen shoulder and elbow musculature that resist distraction as well as improve trunk strength and flexibility to maximize pitching velocity and help prevent injury.     

The relationship between balance and pitching error in college baseball pitchers

The objective of the study was to examine the relationship between balance and pitching error in college baseball pitchers. Sixteen college baseball pitchers, 9 National Association of Intercollegiate Athletics (NAIA) and 7 National Collegiate Athletic Association (NCAA) Division III, participated in the study. Balance ability, expressed as average sway velocity (deg.s(-1)), during dominant leg unilateral stance with eyes open and eyes closed was quantified for each subject utilizing the Balance Master System 7.04 (long force plate). Additionally, each subject underwent sensory organization testing on the SMART EquiTest System providing information regarding the effective use of the somatosensory, visual, and vestibular inputs. Pitching error was assessed with a high-speed video camera recorder during spring practice. A JUGS radar gun measured pitch velocity. The mean pitching error was 37.50 cm with a mean pitch velocity of 78 miles.h(-1) (35 m.s(-1)). No significant correlation was demonstrated between unilateral stance eyes open and pitching error (r = -0.24; p = 0.36) or unilateral stance eyes closed and pitching error (r = -0.29; p = 0.27). A significant negative correlation was demonstrated between sensory organization test 5 and pitching error (r = -0.50; p = 0.05) and between sensory organization test 5/1 and pitching error (r = -0.50; p = 0.05). Additionally, unilateral stance eyes closed demonstrated a positive correlation with pitch velocity (r = 0.52; p = 0.04). The results reveal that low levels of vestibular input utilization may lead to high levels of pitching error in college baseball pitchers.     

Shoulder joint movement of the non-throwing arm during baseball pitch—comparison between skilled and unskilled pitchers

The shoulder of a non-throwing arm during a baseball pitch must be in a constant position while the shoulder of the throwing arm moves in a nearly circular path around it. However, it has not been investigated whether a skilled pitch requires less shoulder-joint movement. It was hypothesized that pitchers with less shoulder movement of the non-throwing arm can be considered to have higher skill and to attain higher initial ball velocity. Nine baseball pitchers were used as subjects. The coach classified them into a skilled and an unskilled group. The pitching motions were recorded using two high-speed cameras. The time series of three-dimensional landmark coordinates of the shoulder joint of the non-throwing arm during the baseball pitch were calculated using the direct linear transformation method. The shoulder-joint movement (SJM) index, which expresses the movement (displacement) of the shoulder joint of the non-throwing arm quantitatively, was proposed to compare the SJM at different skill levels and investigate the relationship between SJM and initial ball velocity. The SJM of the skilled pitchers was smaller than that of the unskilled pitchers, and the smaller value of the SJM led to faster initial ball velocity. The data suggest that the less SJM of the non-throwing arm is required to attain a skilled pitch and higher initial ball velocity.     

The relationship between age and baseball pitching kinematics in professional baseball pitchers

Joint range of motion and physical capacities have been shown to change with age in both throwing athletes and non-athletes. The age of professional baseball pitchers could span from late teens to mid-40s. However, the effects of age on the pitching kinematics among professional baseball pitchers are still unknown. In this study, 67 healthy professional baseball pitchers were tested using a 3D motion analysis system. Their mean age was 23.7+/-3.3 years (range 18.8-34.4). The 12 pitchers more than one standard deviation older than the mean (i.e., older than 27.0 years) were categorized into the older group, and the 10 pitchers more than one standard deviation younger than the mean (i.e., younger than 20.4 years) were defined as the younger group. In all, 18 kinematic variables (14 position and 4 velocity) were calculated, and Student's t-tests were used to compare the variables between the two groups. Six position variables were found to be significantly different between the two groups. At the instant of lead foot contact, the older group had a shorter stride, a more closed pelvis orientation, and a more closed upper trunk orientation. The older group also produced less shoulder external rotation during the arm cocking phase, more lead knee flexion at ball release, and less forward trunk tilt at ball release. Ball velocity and body segment velocity variables showed no significant differences between the two groups. Thus, differences in specific pitching kinematic variables among professional baseball pitchers of different age groups were not associated with significant differences in ball velocities between groups. The current results suggest that both biological changes and technique adaptations occur during the career of a professional baseball pitcher.     

Effects of upper trunk rotation on shoulder joint torque among baseball pitchers of various levels

High rotational torques during baseball pitching are believed to be linked to most overuse injuries at the shoulder. This study investigated the effects of trunk rotation on shoulder rotational torques during pitching. A total of 38 pitchers from the professional, college, high school, and youth ranks were recruited for motion analysis. Professional pitchers demonstrated the least amount of rotational torque (p = .001) among skeletally mature players, while exhibiting the ability to rotate their trunks significantly later in the pitching cycle, as compared to other groups (p = .01). It was concluded that the timing of their rotation was optimized as to allow the throwing shoulder to move with decreased joint loading by conserving the momentum generated by the trunk. These results suggest that a specific pattern in throwing can be utilized to increase the efficiency of the pitch, which would allow a player to improve performance with decreased risk of overuse injury.     

Kinematic and kinetic comparison of baseball pitching among various levels of development

Proper biomechanics help baseball pitchers minimize their risk of injury and maximize performance. However previous studies involved adult pitchers only. In this study, 23 youth, 33 high school, 115 college, and 60 professional baseball pitchers were analyzed. Sixteen kinematic (11 position and five velocity), eight kinetic, and six temporal parameters were calculated and compared among the four levels of competition. Only one of the 11 kinematic position parameters showed significant differences among the four levels, while all five velocity parameters showed significant differences. All eight kinetic parameters increased significantly with competition level. None of the six temporal parameters showed significant differences. Since 16 of the 17 position and temporal parameters showed no significant differences, this study supports the philosophy that a child should be taught ‘proper’ pitching mechanics for use throughout a career. Kinetic differences observed suggest greater injury risk at higher competition levels. Since adult pitchers did not demonstrate different position or temporal patterns than younger pitchers, increases in joint forces and torques were most likely due to increased strength and muscle mass in the higher level athlete. The greater shoulder and elbow angular velocities produced by high-level pitchers were most likely due to the greater torques they generated during the arm cocking and acceleration phases. The combination of more arm angular velocity and a longer arm resulted in greater linear ball velocity for the higher level pitcher. Thus, it appears that the natural progression for successful pitching is to learn proper mechanics as early as possible, and build strength as the body matures.     

The impact of pitch counts and days of rest on performance among major-league baseball pitchers

Although the belief that overuse can harm pitchers is widespread, there exists little evidence to show that the number of pitches thrown and the days of rest affect future performance and injury among adults. The purpose of this study is to quantify the effects of pitches thrown and the days of rest on pitcher performance. We examined performances of major-league baseball starting pitchers from 1988 to 2009 using fractional polynomial multiple regression to estimate the immediate and cumulative impact of pitches thrown and the days of rest on performance, while controlling for other factors that likely affect pitcher effectiveness. Estimates indicate each pitch thrown in the preceding game increased earned run average (ERA) by 0.007 in the following game. Each pitch averaged in the preceding 5 and 10 games increased the ERA by 0.014 and 0.022, respectively. Older pitchers were more sensitive to cumulative pitching loads than younger pitchers were, but they were less affected by pitches thrown in the preceding game. Rest days were weakly associated with performance. In summary, we found that there is a negative relationship between past pitches thrown and future performance that is virtually linear. The impact of the cumulative pitching load is larger than the impact of a single game. Rest days do not appear to have a large impact on performance. This study supports the popular notion that high pitching loads can dampen future performance; however, because the effect is small, pitch-count benchmarks have limited use for maintaining performance and possibly preventing injury.     

Effects of a 4-week youth baseball conditioning program on throwing velocity

Effects of a 4-week youth baseball conditioning program on throwing velocity. This study examined the effects of a 4-week youth baseball conditioning program on maximum throwing velocity. Thirty-four youth baseball players (11-15 years of age) were randomly and equally divided into control and training groups. The training group performed 3 sessions (each 75 minutes) weekly for 4 weeks, which comprised a sport specific warm-up, resistance training with elastic tubing, a throwing program, and stretching. Throwing velocity was assessed initially and at the end of the 4-week conditioning program for both control and training groups. The level of significance used was p < 0.05. After the 4-week conditioning program, throwing velocity increased significantly (from 25.1 ± 2.8 to 26.1 ± 2.8 m·s) in the training group but did not significantly increase in the control group (from 24.2 ± 3.6 to 24.0 ± 3.9 m·s). These results demonstrate that the short-term 4-week baseball conditioning program was effective in increasing throwing velocity in youth baseball players. Increased throwing velocity may be helpful for pitchers (less time for hitters to swing) and position players (decreased time for a runner to advance to the next base).     

Mean muscle activation comparison between fastballs and curveballs with respect to the upper and lower extremity

Baseball research on muscle activity (upper and lower extremity) during the throwing motion is important to understanding pitching mechanics for the future. Therefore, it is the purpose of this research study to compare the lower extremity muscle and upper extremity muscle activation patterns associated with the curveball pitch and the fastball pitch from the stretch position. Twelve skilled (NCAA collegiate level) pitchers volunteered to be in this study, with a mean age of 22.3 ± 4.53 years, mean height of 1.74 ± 0.13 m, and mean mass of 89.0 k ± 10.97 kg. The pitchers were fitted with six surface electromyography (EMG) bipolar electrodes on the stride leg biceps femoris, medial gastrocnemius, ipsilateral side lower trapezius, upper trapezius, triceps brachii and biceps brachii. Each pitcher underwent maximum voluntary isometric contraction (MVIC) testing and then performed the fastball & curveball pitching sequence. All EMG variables of interest were normalized using MVIC data and compared between pitching type. A repeated measures ANOVA was conducted for all muscle activity as well. If significance was found a pairwise analysis (Bonferroni) was performed between pitch type, using SPSS (p 0.05). Significant differences in the mean muscle activity for the fastball and curveball pitched from the stretch were observed. A higher level of muscle activity was found for the stretch fastball when compared to the stretch curveball. This study was able to provide a baseline measurement of muscle activity; however, kinematics and kinetics should be measured in future studies.     

Muscle activation patterns of the upper and lower extremity during the windmill softball pitch

Fast-pitch softball has become an increasingly popular sport for female athletes. There has been little research examining the windmill softball pitch in the literature. The purpose of this study was to describe the muscle activation patterns of 3 upper extremity muscles (biceps, triceps, and rhomboids [scapular stabilizers]) and 2 lower extremity muscles (gluteus maximus and medius) during the 5 phases of the windmill softball pitch. Data describing muscle activation were collected on 7 postpubescent softball pitchers (age 17.7 ± 2.6 years; height 169 ± 5.4 cm; mass 69.1 ± 5.4 kg). Surface electromyographic data were collected using a Myopac Jr 10-channel amplifier (RUN Technologies Scientific Systems, Laguna Hills, CA, USA) synchronized with The MotionMonitor? motion capture system (Innovative Sports Training Inc, Chicago IL, USA) and presented as a percent of maximum voluntary isometric contraction. Gluteus maximus activity reached (196.3% maximum voluntary isometric contraction [MVIC]), whereas gluteus medius activity was consistent during the single leg support of phase 3 (101.2% MVIC). Biceps brachii activity was greatest during phase 4 of the pitching motion. Triceps brachii activation was consistently >150% MVIC throughout the entire pitching motion, whereas the scapular stabilizers were most active during phase 2 (170.1% MVIC). The results of this study indicate the extent to which muscles are activated during the windmill softball pitch, and this knowledge can lead to the development of proper preventative and rehabilitative muscle strengthening programs. In addition, clinicians will be able to incorporate strengthening exercises that mimic the timing of maximal muscle activation most used during the windmill pitching phases.     

A method for detecting the temporal sequence of muscle activation during cycling using MRI

Surface electromyography (EMG) can assess muscle recruitment patterns during cycling, but has limited applicability to studies of deep muscle recruitment and electrically stimulated contractions. We determined whether muscle recruitment timing could be inferred from MRI-measured transverse relaxation time constant (T(2)) changes and a cycle ergometer modified to vary power as a function of pedal angle. Six subjects performed 6 min of single-leg cycling under two conditions (E0°-230° and E90°-230°), which increased the power from 0°-230° and 90-230° of the pedal cycle, respectively. The difference condition produced a virtual power output from 0-180° (V0°-180°). Recruitment was assessed by integrating EMG over the pedal cycle (IEMG) and as the (post-pre) exercise T(2) change (ΔT(2)). For E0°-230°, the mean IEMG for vastus medialis and lateralis (VM/VL; 49.3 ± 3.9 mV·s; mean ± SE) was greater (P < 0.05) than that for E90°-230° (17.9 ± 1.9 mV·s); the corresponding ΔT(2) values were 8.7 ± 1.0 and 1.4 ± 0.5 ms (P < 0.05). For E0°-230° and E90°-230°, the IEMG values for biceps femoris/long head (BF(L)) were 37.7 ± 5.4 and 27.1 ± 5.6 mV·s (P > 0.05); the corresponding ΔT(2) values were 0.9 ± 0.9 and 1.5 ± 0.9 ms (P > 0.05). MRI data indicated activation of the semitendinosus and BF/short head for E0°-230° and E90°-230°. For V0°-180°, ΔT(2) was 7.2 ± 0.9 ms for VM/VL and -0.6 ± 0.6 ms for BF(L); IEMG was 31.5 ± 3.7 mV·s for VM/VL and 10.6 ± 7.0 mV·s for BF(L). MRI and EMG data indicate VM/VL activity from 0 to 180° and selected hamstring activity from 90 to 230°. Combining ΔT(2) measurements with variable loading allows the spatial and temporal patterns of recruitment during cycling to be inferred from MRI data.     

Use of virtual, interactive, musculoskeletal system (VIMS) in modeling and analysis of shoulder throwing activity

Our purpose in this study was to apply the virtual, interactive, musculoskeletal system (VIMS) software for modeling and biomechanical analysis of the glenohumeral joint during a baseball pitching activity. The skeletal model was from VIMS library and muscle fiber attachment sites were derived from the visible human dataset. The muscular moment arms and function changes are mainly due to the large humeral motion involved during baseball pitching. The graphic animation of the anatomic system using VIMS software is an effective tool to model and visualize the complex anatomical structure of the shoulder for biomechanical analysis.     

Influence of shoulder abduction and lateral trunk tilt on peak elbow varus torque for college baseball pitchers during simulated pitching

Elbow varus torque is a primary factor in the risk of elbow injury during pitching. To examine the effects of shoulder abduction and lateral trunk tilt angles on elbow varus torque, we conducted simulation and regression analyses on 33 college baseball pitchers. Motion data were used for computer simulations in which two angles-shoulder abduction and lateral trunk tilt-were systematically altered. Forty-two simulated motions were generated for each pitcher, and the peak elbow varus torque for each simulated motion was calculated. A two-way analysis of variance was performed to analyze the effects of shoulder abduction and trunk tilt on elbow varus torque. Regression analyses of a simple regression model, second-order regression model, and multiple regression model were also performed. Although regression analyses did not show any significant relationship, computer simulation indicated that the peak elbow varus torque was affected by both angles, and the interaction of those angles was also significant. As trunk tilt to the contralateral side increased, the shoulder abduction angle producing the minimum peak elbow varus torque decreased. It is suggested that shoulder abduction and lateral trunk tilt may be only two of several determinants of peak elbow varus torque.     

Comparison of three baseball-specific 6-week training programs on throwing velocity in high school baseball players

Throwing velocity is an important baseball performance variable for baseball pitchers, because greater throwing velocity results in less time for hitters to make a decision to swing. Throwing velocity is also an important baseball performance variable for position players, because greater throwing velocity results in decreased time for a runner to advance to the next base. This study compared the effects of 3 baseball-specific 6-week training programs on maximum throwing velocity. Sixty-eight high school baseball players 14-17 years of age were randomly and equally divided into 3 training groups and a nontraining control group. The 3 training groups were the Throwers Ten (TT), Keiser Pneumatic (KP), and Plyometric (PLY). Each training group trained 3 d·wk(-1) for 6 weeks, which comprised approximately 5-10 minutes for warm-up, 45 minutes of resistance training, and 5-10 for cool-down. Throwing velocity was assessed before (pretest) and just after (posttest) the 6-week training program for all the subjects. A 2-factor repeated measures analysis of variance with post hoc paired t-tests was used to assess throwing velocity differences (p < 0.05). Compared with pretest throwing velocity values, posttest throwing velocity values were significantly greater in the TT group (1.7% increase), the KP group (1.2% increase), and the PLY group (2.0% increase) but not significantly different in the control group. These results demonstrate that all 3 training programs were effective in increasing throwing velocity in high school baseball players, but the results of this study did not demonstrate that 1 resistance training program was more effective than another resistance training program in increasing throwing velocity.     

Injury to the Throwing Arm—A Study of Traumatic Changes in the Elbow Joints of Boy Baseball Players

X-ray studies were made of both elbows of 162 boys in the 9 to 14 year age group, divided into three categories: Pitchers, non-pitchers, and a control group who had never played organized baseball.Changes involving the medial epicondylar epiphysis and opposing articular surfaces of the capitulum and head of radius in the throwing arm appeared to be in direct proportion to the amount and type of throwing. The most striking changes were in the arms of pitchers. Some degree of accelerated growth, separation and fragmentation of the medial epicondylar epiphyses was noted in the throwing arm of all 80 pitchers in the study. Five cases of traumatic osteochondritis of the capitulum and head of radius, and one case of juvenile osteochondritis of the head of the radius were also found among the pitchers.Better medical supervision and stress on prevention are needed, especially in the Southern California area where climatic conditions favor prolonged seasons and throwing practice the year around.     

Differences between two subgroups of low back pain patients in lumbopelvic rotation and symmetry in the erector spinae and hamstring muscles during trunk flexion when standing

The present study was performed to examine lumbopelvic rotation and to identify asymmetry of the erector spinae and hamstring muscles in people with and without low back pain (LBP). The control group included 16 healthy subjects, the lumbar-flexion–rotation syndrome LBP group included 17 subjects, and the lumbar-extension–rotation syndrome LBP group included 14 subjects. Kinematic parameters were recorded using a 3D motion-capture system, and electromyography parameters were measured using a Noraxon TeleMyo 2400T. The two LBP subgroups showed significantly more lumbopelvic rotation during trunk flexion in standing than did the control group. The muscle activity and flexion–relaxation ratio asymmetries of the erector spinae muscles in the lumbar-flexion–rotation syndrome LBP group were significantly greater than those in the control group, and the muscle activity and flexion–relaxation ratio asymmetry of the hamstring muscles in the lumbar-extension–rotation syndrome LBP group were significantly greater than those in the control group. Imbalance or asymmetry of passive tissue could lead to asymmetry of muscular activation. Muscle imbalance can cause asymmetrical alignment or movements such as unexpected rotation. The results showed a greater increase in lumbopelvic rotation during trunk flexion in standing among the lumbar-flexion–rotation syndrome and lumbar-extension–rotation syndrome LBP groups compared with the control group. The differences between the two LBP subgroups may be a result of imbalance and asymmetry in erector spinae and hamstring muscle properties.     

Single-leg cycle training is superior to double-leg cycling in improving the oxidative potential and metabolic profile of trained skeletal muscle

Single-leg cycling may enhance the peripheral adaptations of skeletal muscle to a greater extent than double-leg cycling. The purpose of the current study was to determine the influence of 3 wk of high-intensity single- and double-leg cycle training on markers of oxidative potential and muscle metabolism and exercise performance. In a crossover design, nine trained cyclists (78 ± 7 kg body wt, 59 ± 5 ml·kg(-1)·min(-1) maximal O(2) consumption) performed an incremental cycling test and a 16-km cycling time trial before and after 3 wk of double-leg and counterweighted single-leg cycle training (2 training sessions per week). Training involved three (double) or six (single) maximal 4-min intervals with 6 min of recovery. Mean power output during the single-leg intervals was more than half that during the double-leg intervals (198 ± 29 vs. 344 ± 38 W, P < 0.05). Skeletal muscle biopsy samples from the vastus lateralis revealed a training-induced increase in Thr(172)-phosphorylated 5'-AMP-activated protein kinase α-subunit for both groups (P < 0.05). However, the increase in cytochrome c oxidase subunits II and IV and GLUT-4 protein concentration was greater following single- than double-leg cycling (P < 0.05). Training-induced improvements in maximal O(2) consumption (3.9 ± 6.2% vs. 0.6 ± 3.6%) and time-trial performance (1.3 ± 0.5% vs. 2.3 ± 4.2%) were similar following both interventions. We conclude that short-term high-intensity single-leg cycle training can elicit greater enhancement in the metabolic and oxidative potential of skeletal muscle than traditional double-leg cycling. Single-leg cycling may therefore provide a valuable training stimulus for trained and clinical populations.