The purpose of this study was to examine the relationships between pitcher trunk and throwing arm girth with kinematics at ball release of the softball pitch. Softball pitchers can be of various ...shapes and sizes; however, it is unknown if segment girth might influence pitch biomechanics. Because of the importance of body positioning at ball release of the windmill pitch, this study examined the relationship between segment girth and pitch biomechanics at ball release.
Forty-two pitchers volunteered to participate (1.706 ± 0.061 m, 74.98 ± 15.94 kg, 15.5 ± 1.7 yr). Participants' throwing upper arm, chest, waist, and hip girth were measured. Participants then pitched fastballs to a catcher (43 ft) while an electromagnetic motion capture system synced with a force plate and motion analysis software collected kinematic data (sampled at 240 Hz).
Linear regressions revealed that upper arm, chest, and waist girth were associated with throwing arm shoulder horizontal abduction. Greater segment girth was associated with less horizontal abduction at ball release of the pitch.
Segment girth is related to pitch biomechanics and may influence body positions at crucial softball pitch events such as ball release.
Understanding biomechanical differences according to body segment girth is important for safe and optimal player development and performance.
Giordano, KA, Cassidy, MM, and Oliver, GD. Length-tension differences between concentric and eccentric shoulder rotation strength. J Strength Cond Res 38(2): 253-258, 2024-Eccentric contractions ...generally produce more force than concentric contractions. However, if length-tension relationships affect both contractions equally remains unknown. Therefore, our purpose was to compare concentric versus eccentric shoulder external and internal rotation strength across a continuous 90° arc. Fifty-two physically active individuals performed isokinetic concentric and eccentric shoulder external rotation and internal rotation through a 90° arc (forearm horizontal to forearm vertical) with the shoulder elevated in both the frontal and scapular planes. Statistical parametric mapping analysis compared concentric and eccentric trials within subjects. Frontal plane eccentric external rotation torque was greater than concentric 30°-90° (p < 0.01) external rotation, and concentric external rotation torque was greater 5°-15° external rotation (p = 0.01). Frontal plane, eccentric internal rotation torque was greater than concentric 15°-55° external rotation (p < 0.01), and concentric torque was greater at forearm horizontal (p = 0.05) and 70°-90° external rotation (p < 0.01). Scapular plane eccentric external rotation torque was greater than concentric 30°-90° external rotation (p < 0.01) and concentric external rotation torque was greater 5°-20° external rotation (p < 0.01). Scapular plane eccentric internal rotation torque was greater than concentric 15°-60° external rotation (p < 0.01), and concentric torque was greater at forearm horizontal (p = 0.05) and 78°-90° external rotation (p = 0.02). Coaches, clinicians, and researchers should interpret data from studies reporting isokinetic data with the understanding that isokinetic peak strength values are not comparing the same muscle length and are not an appropriate measure for all muscle lengths. Furthermore, shoulder stability is affected through decreased eccentric force production at end ranges of shoulder rotation.
The purpose of this study was to examine the relationship between whole body and throwing arm composition and length with throwing shoulder distraction and anterior force. Literature shows a ...relationship between shoulder force and pain; therefore, as well as between body mass and pain, it was hypothesized that pitchers with greater body fat mass would display increased throwing shoulder force during the acceleration phase of the softball pitch.
Thirty-eight high school softball pitchers from southern United States agreed to participate (1.69 ± 0.07 m, 74.71 ± 16.36 kg, 15.2 ± 1.1 yr). All procedures were completed within one visit. Pitchers underwent a dual-energy x-ray absorptiometry scan then threw fastballs at regulation distance while motion was measured using an electromagnetic motion capture system. Data from the three fastest pitches were averaged and analyzed. Peak shoulder distraction and anterior force during the acceleration phase of the softball pitch were extracted and used as dependent variables in two separate regression analyses. Whole body and throwing arm fat mass and lean mass, as well as throwing arm length were entered as independent variables into both regression equations.
The first regression equation was statistically significant (F(5,37) = 13.28, P < 0.001) and explained approximately 62% of the variance in peak shoulder distraction force (R2 = 0.675, adjusted R2 = 0.624). Increased whole body fat mass (B = 13.76, SE = 5.39, β = 0.91, t = 2.553, P = 0.016) significantly predicted peak throwing shoulder distraction force. The second regression equation predicting peak anterior force was not significant.
Increased fat mass may exacerbate the high force observed at the throwing shoulder and further increase injury susceptibility to pitchers.
Most human movement research takes place within controlled laboratories where researchers observe participant movement. Because a majority of daily activity is performed without observation, we ...hypothesized movement within a laboratory would vary when there was a small, large or absence of research group. We also hypothesized that personality type would influence movement during observation. Participants completed a personality questionnaire, then walked in a laboratory during three different conditions: no research group (no researchers), small research group (2 researchers), and large research group (6-10 researchers). Results revealed spatiotemporal parameters were altered between conditions, however personality type did not influence changes in movement. As the number of researchers increased, gait speed, cadence, and stride length increased, and step duration decreased. Gait speed increased by .03 m/s from the no research group to the small research group, by .06 m/s from the no research group to the large research group, and by .03 m/s from the small to large research group (all p values < .001). Understanding how researcher observation modifies movement is important and affects the replicability of results, as well as the interpretation of laboratory-based movement studies to activities of daily living in real world settings.
Background:
Softball pitchers exhibit high throwing shoulder distraction force, which is a theorized mechanism of throwing shoulder overuse injury. Windmill pitching involves a variety of highly ...individualistic pitching styles, and certain kinematics preceding ball release likely influence the amount of shoulder stress that a pitcher accrues.
Purpose:
To examine the association of trunk and throwing arm kinematics, kinetics, and timing variables with peak throwing shoulder distraction force in high school softball pitchers.
Study Design:
Descriptive laboratory study.
Methods:
A total of 37 high school pitchers (mean ± SD; height, 1.71 ± 0.06 m; weight, 75.53 ± 16.12 kg; age, 16 ± 2 years) threw 10 fastball pitches at regulation distance (43 ft 13.1 m) and with maximum effort. Kinematic data were collected at 240 Hz using an electromagnetic motion capture system synced with motion analysis software. The 3 fastest pitches were averaged and analyzed. Kinematic, kinetic, and timing variables were entered into a stepwise linear regression analysis.
Results:
Four variables were included in the significant model (F4,39 = 147.51; P < .001) and explained peak shoulder distraction force (R2 = 0.944; adjusted R2 = 0.938; SE = 0.036): increased peak elbow distraction force (t = 19.90; P < .001) and extension moment (t = 3.63; P = .001), as well as decreased elbow flexion velocity (t = −2.37; P = .023) and trunk flexion at foot contact of the pitch (t = −3.00; P = .005).
Conclusion:
Elbow kinetics and angular velocity, as well as trunk positioning at foot contact, are associated with peak throwing shoulder distraction force in high school softball pitchers.
Clinical Relevance:
Variables associated with peak throwing shoulder distraction force provide information regarding injury mechanism and coachable cues that might reduce shoulder injury risk among pitchers.
Strength testing of shoulder rotation is commonly used in clinical examinations of the shoulder. People prone to shoulder injury, such as overhead athletes and manual trade workers, place their ...shoulders under tremendous amounts of stress when the cervical spine is in nonneutral positions. If these nonneutral cervical spine positions result in decreased shoulder strength, it may help explain the etiology of the high prevalence of shoulder injuries in these populations. Given standard clinical strength assessments are performed with a neutral cervical spine, an investigation into the effects of cervical spine rotation is warranted.
We sought to compare isokinetic shoulder rotation strength while in a neutral position with rotated cervical spine positions, specifically (1) with the cervical spine rotated contralaterally with the shoulder elevated in the frontal plane and (2) with the cervical spine rotated ipsilaterally and the shoulder elevated in the scapular plane.
A convenience sample of 52 individuals (height 170 ± 10 cm; weight 73 ± 18 kg, age 21 ± 2 years; 18 males, 34 females), without shoulder or cervical spine pathology participated in this study. Participants were screened for eligibility via questionnaire. Concentric shoulder internal and external rotation torque was measured through a 90° arc on an isokinetic dynamometer with the shoulder elevated 90° in the frontal plane, and again 45° anterior to the frontal plane (scapular plane). Two repetitions were performed in a single testing session with the participant's cervical spine in neutral in both planes, maximally rotated contralaterally in the frontal plane, and maximally rotated ipsilaterally with the shoulder in the scapular plane; the second repetition was used for analysis. The testing order was randomized. Data were imported into a platform for statistical parametric mapping analysis (a technique that allows data from the entire arc of motion to be compared with data from another arc to identify differences in the wave form) to compare strength between positions throughout 90° arc of motion.
Rotating the cervical spine contralaterally with the shoulder in the frontal plane resulted in a decrease in external (2.24 Nm or 12% average difference; p < 0.001) and internal (2.22 Nm or a 6% average difference; p = 0.02) rotation strength with the forearm within 15° and 20° of the vertical position. Rotating the cervical spine ipsilaterally with the shoulder in the scapular plane resulted in a decrease in external rotation strength (1.27 Nm or a 6% average difference; p < 0.001) throughout nearly all the motion, with peaks approximately 20° and 60° from the horizontal position, and internal rotation strength (1.78 Nm or 5% average difference; p < 0.001) the last 60° towards the horizontal position.
Patient populations who require strenuous use of their shoulders in altered cervical spine positions may be at increased risk for injury from decreased shoulder rotator strength.
Clinicians should assess shoulder strength in the position the patient requires to use their shoulder because cervical spine position may cause weakness that would be missed in standard testing positions.
Recently, an emphasis has been placed on understanding how ovarian sex hormones and hormonal contraceptives affect risk for anterior cruciate ligament (ACL) injury. The literature presents large ...discrepancies in whether or not hormonal contraceptives affect ACL injury risk; therefore, the purpose of this study was to evaluate whether vertical ground reaction force (GRF) and knee valgus force are different between athletes who do and do not use hormonal contraceptives. Twenty-two female athletes volunteered to participate and were divided into two groups based on their answers to a health history questionnaire: those who use hormonal contraceptives and those who do not. Participants performed a drop vertical jump (DVJ) and single leg crossover dropdown (SCD) at two different time points in their menstrual cycle (pre-ovulatory phase and mid-luteal phase). Kinetic data were collected at 1000 Hz. Independent samples t-tests revealed no significant differences between groups in vertical GRF and knee valgus force at both time points. Findings from this study suggest that hormonal contraceptives do not elicit detectable changes in vertical GRF and knee valgus force. Ultimately, this calls for further studies on the relationship between hormones and ACL injury risk and physicians to consider hormonal screening in addition to neuromuscular and biomechanical screening.
Inadequate hip range of motion (ROM) and isometric strength (ISO) may interfere with energy flow through the kinetic chain and result in increased injury susceptibility.
To examine the relationship ...of hip ROM and ISO with energy flow through the trunk and pitching-arm segments during the windmill softball pitch in youth athletes. A subsequent purpose was to examine the relationship between energy flow and pitch speed.
Descriptive laboratory study.
University research laboratory.
A sample of 29 youth softball pitchers (age = 11.2 ± 1.3 years, height = 155.0 ± 10.4 cm, mass = 53.2 ± 12.6 kg).
Bilateral hip internal-rotation and external-rotation (ER) ROM and ISO were measured. Net energy outflow and peak rates of energy outflow from the distal ends of the trunk, humerus, and forearm were calculated for the acceleration phase of the windmill softball pitch, and pitch speed was measured.
Regression analysis revealed an effect of drive-hip ER ISO on the net energy flow out of the distal ends of the trunk (P = .045) and humerus (P = .002). Specifically, increased drive-hip ER ISO was associated with increased net energy outflow from the trunk to the humerus and from the humerus to the forearm. No significant effects of hip ROM or other hip ISO measures were observed. Additionally, pitchers who achieved higher peak rates of distal outflow tended to achieve higher pitch speeds.
An association was present between drive-hip ER ISO and the net energy flow out of the distal ends of the trunk and humerus during the acceleration phase of the windmill softball pitch, emphasizing the importance of hip and lower body strength in executing the whole-body windmill pitch. Overall, energy-flow analysis is an interesting new way to analyze pitching mechanics and will aid in furthering our understanding of performance and injury risk in windmill softball pitching.
As the biomechanical literature concerning softball pitching is evolving, there are no data to support the mechanics of softball position players. Pitching literature supports the whole kinetic chain ...approach including the lower extremity in proper throwing mechanics. The purpose of this project was to examine the gluteal muscle group activation patterns and their relationship with shoulder and elbow kinematics and kinetics during the overhead throwing motion of softball position players. Eighteen Division I National Collegiate Athletic Association softball players (19.2 ± 1.0 years; 68.9 ± 8.7 kg; 168.6 ± 6.6 cm) who were listed on the active playing roster volunteered. Electromyographic, kinematic, and kinetic data were collected while players caught a simulated hit or pitched ball and perform their position throw. Pearson correlation revealed a significant negative correlation between non-throwing gluteus maximus during the phase of maximum external rotation to maximum internal rotation (MIR) and elbow moments at ball release (
r
= −0.52). While at ball release, trunk flexion and rotation both had a positive relationship with shoulder moments at MIR (
r
= 0.69,
r
= 0.82, respectively) suggesting that the kinematic actions of the pelvis and trunk are strongly related to the actions of the shoulder during throwing.
The purpose of this study was to compare measures of bilateral shoulder and hip range of motion (ROM) between youth softball pitchers and position players. Fifty-two youth softball athletes (12.7±2.1 ...yrs.; 160.28±10.98 cm; 59.31±15.07 kg) participated. Bilateral hip and shoulder ROM were measured among pitchers (n=29) and position players (n=23). A 2 (pitcher/position player) × 2 (dominant/non-dominant) ANOVA was performed for both internal and external rotation ROM for the shoulder and hip. Paired sample t-tests were also conducted to examine side-to-side differences in total ROM. Data revealed a significant interaction between position and side dominance. Specifically, position players have significantly more non-dominant shoulder external rotation ROM (106.92°± 9.14°) than pitchers (100.12°± 11.21°). There were no significant differences between throwing and non-throwing sides. It is important that coaches and clinicians are aware of these adaptations between overhand and underhand throwing in order to properly develop conditioning and rehabilitation programs to alleviate injury susceptibility and cater to position-specific demands. Additionally, the current data suggest many of the functional adaptations seen within older populations are not fully developed until after youth.
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