scholarly journals Arm abduction angle at ball release influences shoulder forces and torques during the windmill softball pitch

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0040
Author(s):  
Donna Scarborough ◽  
Ryan Fallon ◽  
Eric Berkson ◽  
Luke Oh, Shannon Linderman
Keyword(s):  
Shoulder Pain ◽  
Shoulder Joint ◽  
High Speed ◽  
Frontal Plane ◽  
Abduction Angle ◽  
Shoulder Abduction ◽  
Compression Force ◽  
Ball Release ◽  
Shoulder Flexion ◽  
Relationship Of

Objectives: Shoulder pain and ligamentous injury is a common complaint among fast pitch softball pitchers. In addition to extreme shoulder joint motion during pitch delivery, sudden deceleration immediately after ball release places increased stress across the shoulder joint. Some pitchers release the ball with the throwing arm tucked close to the trunk, while others let the arm float outwards in a more abducted position. The position of the arm at ball release (BR) may be key to the mechanism of shoulder pain. Previous work demonstrated that during the change up pitch, softball pitchers with upper extremity pain demonstrated greater shoulder abduction at stride and less trunk lateral flexion at BR compared to athletes without pain (Oliver et al 2018). The purpose of this study was to test the hypothesis that placement of the arm closer to the trunk (shoulder adduction) at ball release will produce less shoulder stress during fastball windmill pitches. Methods: Twenty-six female fast pitch softball pitchers with a mean age of 18 +/- 6 y, including 16 high school, 7 collegiate, and 3 professional athletes, underwent 3D biomechanical pitch analyses using 20 Vicon high-speed motion capture cameras (240 hz). All pitchers threw the standard 13.11 m mound-to-plate distance at a strike zone target while a radar gun collected pitch speeds. The fastest, most accurate fastball pitches for each subject were selected for analyses (average of 5 pitches per subject). A total of 103 pitches were used to calculate: shoulder abduction angle and shoulder compression force during the BR phase (10 frames surrounding BR) and peak shoulder torques. Pearson correlations were performed to determine the relationship of shoulder frontal plane (adduction/abduction) angle during the ball release phase to these biomechanical measures. Results: The smallest abduction shoulder angle reached during the BR phase (avg: 14.06 +/- 6.71 degrees) demonstrated a significant positive correlation with shoulder compression force, p=0.008 and with peak flexion torque, p< 0.001 (Table 1). This shoulder abduction angle during the BR phase demonstrated negative correlations with peak shoulder adduction torque, p<0.001 and shoulder internal rotation torque, p< 0.001. Conclusion: These initial findings support the hypothesis that pitchers who release the ball with their arm close to their trunk demonstrate lower shoulder compression forces and shoulder flexion torques than those with a more abducted arm position. Future studies are needed to explore the interplay of pitching technique mechanics, shoulder joint stresses, and injury history to inform pitching instruction and injury prevention efforts. [Table: see text]

Optimal Shoulder Abduction Angles during Baseball Pitching from Maximal Wrist Velocity and Minimal Kinetics Viewpoints

2002 ◽  
Vol 18 (4) ◽  
pp. 306-320 ◽  
Author(s):  
Tomoyuki Matsuo ◽  
Tsuyoshi Matsumoto ◽  
Yoshiyuki Mochizuki ◽  
Yoshihiro Takada ◽  
Kenji Saito
Keyword(s):  
High Speed ◽  
Abduction Angle ◽  
Shoulder Abduction ◽  
Ball Speed ◽  
Kinematic Data ◽  
Reasonable Approximation ◽  
Ball Velocity ◽  
Baseball Coaches

Baseball coaches train pitchers to keep their shoulder abduction at 90º during delivery, because this angle is believed to maximize ball speed and reduce the stress on the throwing arm. In fact, however, the shoulder abduction angle for some pitchers, including professional pitchers, deviates from 90º. There likely are reasons for such deviation. The purposes of this study, therefore, were to investigate the effects of shoulder abduction angle on ball velocity and on the injury-related joint kinetic variable, and to determine why the shoulder abduction angle varies among pitchers. Eleven professional pitchers were videotaped with two high-speed cameras. The resulting kinematic data were used to simulate several pitching motions by varying the shoulder abduction angle from the actual angle. Maximum wrist velocity was used as a reasonable approximation of ball velocity. Elbow varus torque was used as a kinetic variable. The square torque for the throwing arm and torque change for the throwing arm were used to investigate the cause of the variation. It was found that the shoulder abduction angle of 90º did not always maximize wrist velocity nor minimize elbow varus torque. The actual shoulder abduction angle for each pitcher was highly consistent with the angle that minimized both square torque and torque change. The results suggested that the proficient throwers in this study moved their pitching arm so as to minimize mechanical cost while at the same time optimizing performance.

Measurement of Shoulder Abduction Angles in Dogs: An Ex Vivo Study of Accuracy and Repeatability

2019 ◽  
Vol 32 (06) ◽  
pp. 427-432
Author(s):  
Stephen C. Jones ◽  
James Howard ◽  
Judith Bertran ◽  
Brittney Johnson ◽  
Antonio Pozzi ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Repeated Measurements ◽  
Abduction Angle ◽  
Shoulder Abduction ◽  
Support Structures ◽  
Shoulder Joints ◽  
Shoulder Flexion ◽  
Experienced Observer ◽  
Accuracy And Repeatability ◽  
Ex Vivo Study

Objective The aim of this study was to determine the accuracy and repeatability of the shoulder abduction test and to assess the effect of transection of the medial shoulder support structures in canine cadavers. Materials and Methods The shoulder abduction angle was measured by three separate observers, both with the shoulder extended and at a neutral angle. Shoulder abduction was then measured, using craniocaudal fluoroscopic images. Arthroscopy was performed in all shoulder joints, with the medial support structures transected in one shoulder of each dog. The three observers again measured shoulder abduction angles in all dogs. Shoulder abduction was measured again using fluoroscopy. Accuracy and repeatability of the abduction test were assessed using linear mixed models. Results All three observers had different measured abduction angles when compared with fluoroscopy (p < 0.01); however, the experienced surgeon had an error of only 2.9°. Inter-observer repeatability was poor, with all three observers having different abduction measurements (p < 0.001). Intra-observer repeatability, however, indicated no differences on repeated measurements (p = 0.26). Placing the shoulder at a neutral standing angle, and transection of support structures caused an average increase in abduction by 8.2° (p < 0.001) and 4.4° respectively. Conclusion Significant variation exists between observers performing this test, increased accuracy seen in the more experienced observer. Shoulder flexion angle can significantly affect measured abduction angles.

scholarly journals Biomechanical Differences Between Japanese and American Professional Baseball Pitchers

2019 ◽  
Vol 7 (2) ◽  
pp. 232596711982562 ◽  
Author(s):  
Takanori Oi ◽  
Shinichi Yoshiya ◽  
Jon Slowik ◽  
Alek Diffendaffer ◽  
Yohei Takagi ◽  
...  
Keyword(s):  
Knee Flexion ◽  
The United States ◽  
Abduction Angle ◽  
Professional Baseball ◽  
Shoulder Abduction ◽  
Elbow Injury ◽  
Risk Of Injury ◽  
Ball Release ◽  
Increased Risk ◽  
Baseball Pitchers

Background: Although baseball injuries are common in both Japan and the United States, the majority of pitching injuries in Japanese players occur at the shoulder, whereas most pitching injuries in American players occur at the elbow. A biomechanical comparison between Japanese and American pitchers may help to identify the different injury mechanisms. Hypothesis: Japanese pitchers produce greater shoulder kinetics whereas American pitchers generate greater elbow kinetics. Also, kinematic differences will be found between the 2 groups, including longer stride and greater lead knee flexion for Japanese pitchers. Study Design: Descriptive laboratory study. Methods: Biomechanical data for 19 Japanese professional baseball pitchers and an age-matched group of 19 American professional baseball pitchers were collected by use of a 3-dimensional, automated, high-speed optical motion capture system. Anthropometric, kinetic, and kinematic data for both groups were compared by use of t tests ( P < .05). Results: American pitchers were taller and heavier and generated greater ball velocity (38.1 ± 1.6 vs 34.7 ± 1.1 m/s; P < .001) than their Japanese counterparts. Most elbow and shoulder kinetic parameters, including elbow varus torque (99 ± 17 vs 86 ± 17 N·m; P = .018), were greater for American pitchers. However, when normalized by bodyweight and height, shoulder horizontal adduction torque was greater for Japanese pitchers (6.8% ± 1.0% vs 5.8% ± 1.1%; P = .005). Japanese pitchers had longer stride (86% ± 5% vs 82% ± 6% of height; P = .023), greater shoulder abduction at ball release (101° ± 8° vs 94° ± 9°; P = .014), and greater knee flexion after ball release (39° ± 18° vs 28° ± 14°; P = .039). Japanese pitchers also demonstrated greater shoulder internal rotation velocity, elbow flexion, and elbow extension velocity. Conclusion: Greater elbow varus torque may predispose American pitchers to greater risk of elbow injury. Japanese pitchers may have increased risk of shoulder injury due to greater normalized horizontal adduction torque and greater abduction angle. Japanese pitchers may be able to reduce their shoulder torque and risk of injury by shortening their stride, reducing their lead knee flexion, and decreasing their throwing arm abduction. Clinical Relevance: Understanding anthropometric, kinetic, and kinematic differences between pitchers from the 2 countries may be of value to clinicians and coaches working to maximize performance of the pitchers while minimizing the risk of injury.

scholarly journals Treatment of myofascial trigger points of the infraspinatus is effective in relieving shoulder pain and improving shoulder functions: A randomized clinical trial

2020 ◽  
Author(s):  
Sungeon Park ◽  
Joochul Cho ◽  
Seungwon Lee
Keyword(s):  
Rotator Cuff ◽  
Shoulder Pain ◽  
Trigger Points ◽  
Shoulder Abduction ◽  
Dash Score ◽  
Myofascial Trigger Points ◽  
Pressure Threshold ◽  
Shoulder Flexion ◽  
Infraspinatus Muscle ◽  
Pain Pressure Threshold

Abstract Background This study aimed to investigate the effects of ischemic compression treatment (ICT) and low-level laser therapy (LLLT) applied on the trigger points of the infraspinatus muscle on shoulder pain and function in patients with shoulder pain. Methods Thirty patients with shoulder pain were randomly categorized into the ICT group (n = 15) and LLLT groups (n = 15). ICT was performed on three myofascial trigger points (MTrPs) of the infraspinatus muscle twice a week for 4 weeks (eight sessions), with 5 minutes of treatment per trigger point. LLLT was performed similarly. Shoulder pain was assessed using the visual analogue scale (VAS) and pain pressure threshold (PPT), and shoulder function was assessed using the Korean Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, rotator cuff strength, and range of motion (ROM) of shoulder flexion and abduction. Results Significant changes in VAS score and PPT were found after the intervention in both groups (p < 0.05). Significant changes were observed in the Korean DASH score, rotator cuff strength, and ROM of shoulder flexion (p < 0.05) but not in the ROM of shoulder abduction (p < 0.05). There were no significant differences between the two groups. Conclusion This study showed that both ICT and LLLT applied on the MTrPs of the infraspinatus muscle were effective for relieving shoulder pain and improving shoulder functions in patients with shoulder pain.

Estimation of Shoulder Behavior From the Viewpoint of Minimized Shoulder Joint Load Among Adolescent Baseball Pitchers

2018 ◽  
Vol 46 (12) ◽  
pp. 3007-3013 ◽  
Author(s):  
Hiroshi Tanaka ◽  
Toyohiko Hayashi ◽  
Hiroaki Inui ◽  
Tomoyuki Muto ◽  
Hiroki Ninomiya ◽  
...  
Keyword(s):  
Shoulder Pain ◽  
Reaction Force ◽  
Shoulder Abduction ◽  
Joint Reaction Force ◽  
Ball Release ◽  
Rotational Position ◽  
Dimensional Measurements ◽  
Baseball Pitchers ◽  
Joint Load ◽  
Anterior Posterior

Background: During pitching, an overloaded joint reaction force exerted on the shoulder and excessive shoulder horizontal abduction at ball release are considered risk factors causing anterior shoulder pain for young baseball pitchers. Hypothesis/Purpose: The first aim was to examine the relationship between shoulder horizontal abduction position and force on the shoulder at ball release. The second was to identify the relative rotational position of the shoulder and the range of shoulder motion at ball release that minimize force on the shoulder. It was hypothesized that the amount of force on the shoulder would be exacerbated by excessive shoulder horizontal abduction. Study Design: Descriptive laboratory study. Methods: Participants were 183 adolescent baseball pitchers (mean ± SD age, 15.5 ± 1.2 years) without shoulder/elbow problems. Each pitcher threw 5 fastballs to a catcher behind a home plate. The kinematics and kinetics of the throwing shoulder during fastball pitching were calculated with 3-dimensional measurements from 36 reflective markers. In data analysis, the correlations were calculated between the relative rotational positions of the shoulder (abduction, horizontal adduction-abduction) and the forces on the shoulder (anterior-posterior, proximal, and superior-inferior) at ball release. Subsequently, the specific rotational position and range of motion of the shoulder at ball release that minimized forces on the shoulder were determined. Results: Statistically significant correlations were identified between the magnitude of superior-inferior force on the shoulder and shoulder abduction position ( R2 = 0.44, P < .001) as well as between the magnitude of anterior-posterior force on the shoulder and shoulder horizontal adduction-abduction position ( R2 = 0.72, P < .001). Minimal anterior-posterior and superior-inferior forces were obtained with a combination of 80.6° of shoulder abduction and 10.7° of shoulder horizontal adduction. Any deviation >5° from this position significantly increased the anterior-posterior and superior-inferior forces on the shoulder. Conclusion: Increasing shoulder horizontal abduction position significantly increased the magnitude of anterior force on the shoulder at ball release. The combination of 80.6° of shoulder abduction and 10.7° of horizontal shoulder adduction minimized the shear forces on the shoulder at this point. Clinical Relevance: The present data can be useful for screening pitching technique to prevent shoulder pain and injury with motion capture assessment.

scholarly journals Shoulder Taping and Neuromuscular Control

2018 ◽  
Vol 53 (4) ◽  
pp. 395-403 ◽  
Author(s):  
Suzanne J. Snodgrass ◽  
Scott F. Farrell ◽  
Henry Tsao ◽  
Peter G. Osmotherly ◽  
Darren A. Rivett ◽  
...  
Keyword(s):  
Shoulder Pain ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Neuromuscular Control ◽  
Optimal Time ◽  
Emg Activity ◽  
Shoulder Abduction ◽  
Corticomotor Excitability ◽  
Upper Trapezius ◽  
Shoulder Flexion

Context:  Scapular taping can offer clinical benefit to some patients with shoulder pain; however, the underlying mechanisms are unclear. Understanding these mechanisms may guide the development of treatment strategies for managing neuromusculoskeletal shoulder conditions. Objective:  To examine the mechanisms underpinning the benefits of scapular taping. Design:  Descriptive laboratory study. Setting:  University laboratory. Patients or Other Participants:  A total of 15 individuals (8 men, 7 women; age = 31.0 ± 12.4 years, height = 170.9 ± 7.6 cm, mass = 73.8 ± 14.4 kg) with no history of shoulder pain. Intervention(s):  Scapular taping. Main Outcome Measure(s):  Surface electromyography (EMG) was used to assess the (1) magnitude and onset of contraction of the upper trapezius (UT), lower trapezius (LT), and serratus anterior relative to the contraction of the middle deltoid during active shoulder flexion and abduction and (2) corticomotor excitability (amplitude of motor-evoked potentials from transcranial magnetic stimulation) of these muscles at rest and during isometric abduction. Active shoulder-flexion and shoulder-abduction range of motion were also evaluated. All outcomes were measured before taping, immediately after taping, 24 hours after taping with the original tape on, and 24 hours after taping with the tape removed. Results:  Onset of contractions occurred earlier immediately after taping than before taping during abduction for the UT (34.18 ± 118.91 milliseconds and 93.95 ± 106.33 milliseconds, respectively, after middle deltoid contraction; P = .02) and during flexion for the LT (110.02 ± 109.83 milliseconds and 5.94 ± 92.35 milliseconds, respectively, before middle deltoid contraction; P = .06). These changes were not maintained 24 hours after taping. Mean motor-evoked potential onset of the middle deltoid was earlier at 24 hours after taping (tape on = 7.20 ± 4.33 milliseconds) than before taping (8.71 ± 5.24 milliseconds, P = .008). We observed no differences in peak root mean square EMG activity or corticomotor excitability of the scapular muscles among any time frames. Conclusions:  Scapular taping was associated with the earlier onset of UT and LT contractions during shoulder abduction and flexion, respectively. Altered corticomotor excitability did not underpin earlier EMG onsets of activity after taping in this sample. Our findings suggested that the optimal time to engage in rehabilitative exercises to facilitate onset of trapezius contractions during shoulder movements may be immediately after tape application.

Roller–rail parameters on the transverse vibration characteristics of super-high-speed elevators

2019 ◽  
Vol 43 (4) ◽  
pp. 535-543 ◽  
Author(s):  
Shunxin Cao ◽  
Ruijun Zhang ◽  
Shuohua Zhang ◽  
Shuai Qiao ◽  
Dongsheng Cong ◽  
...  
Keyword(s):  
High Speed ◽  
Relative Displacement ◽  
Guide Rail ◽  
Coupled Vibration ◽  
Vibration Acceleration ◽  
Vibration Model ◽  
Vibration Problems ◽  
Equivalent Method ◽  
Relationship Of ◽  
The Relationship

Interaction and wear between wheel and rail become increasingly serious with the increase in elevator speed and load. Uneven roller surface, eccentricity of rollers, and the looseness of rail brackets result in serious vibration problems of high-speed and super-high-speed elevators. Therefore, the forced vibration differential equation representing elevator guide rails is established based on Bernoulli–Euler theory, and the vibration equation of the elevator guide shoes and the car is constructed using the Darren Bell principle. Then, the coupled vibration model of guide rail, guide shoes, and car can be obtained using the relationship of force and relative displacement among these components. The roller–rail parameters are introduced into the established coupled vibration model using the model equivalent method. Then, the influence of roller–rail parameters on the horizontal vibration of super-high-speed elevator cars is investigated. Roller eccentricity and the vibration acceleration of the car present a linear correlation, with the amplitude of the car vibration acceleration increasing with the eccentricity of the roller. A nonlinear relationship exists between the surface roughness of the roller and the vibration acceleration of the car. Increased continuous loosening of the guide rail results in severe vibration of the car at the loose position of the support.

scholarly journals Relationship Between 2-Dimensional Frontal Plane Measures and the Knee Abduction Angle During the Drop Vertical Jump

2019 ◽  
Vol 28 (4) ◽  
Author(s):  
Brad W. Willis ◽  
Katie Hocker ◽  
Swithin Razu ◽  
Aaron D. Gray ◽  
Marjorie Skubic ◽  
...  
Keyword(s):  
Motion Capture ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Ligament Injury ◽  
Coefficient Of Determination ◽  
Abduction Angle ◽  
Initial Contact ◽  
Knee Abduction ◽  
The Relationship ◽  
Drop Vertical Jump

Context: Knee abduction angle (KAA), as measured by 3-dimensional marker-based motion capture systems during jump-landing tasks, has been correlated with an elevated risk of anterior cruciate ligament injury in females. Due to the high cost and inefficiency of KAA measurement with marker-based motion capture, surrogate 2-dimensional frontal plane measures have gained attention for injury risk screening. The knee-to-ankle separation ratio (KASR) and medial knee position (MKP) have been suggested as potential frontal plane surrogate measures to the KAA, but investigations into their relationship to the KAA during a bilateral drop vertical jump task are limited. Objective: To investigate the relationship between KASR and MKP to the KAA during initial contact of the bilateral drop vertical jump. Design: Descriptive. Setting: Biomechanics laboratory. Participants: A total of 18 healthy female participants (mean age: 24.1 [3.88] y, mass: 65.18 [10.34] kg, and height: 1.63 [0.06] m). Intervention: Participants completed 5 successful drop vertical jump trials measured by a Vicon marker-based motion capture system and 2 AMTI force plates. Main Outcome Measure: For each jump, KAA of the tibia relative to the femur was measured at initial contact along with the KASR and MKP calculated from planar joint center data. The coefficient of determination (r2) was used to examine the relationship between the KASR and MKP to KAA. Results: A strong linear relationship was observed between MKP and KAA (r2 = .71), as well as between KASR and KAA (r2 = .72). Conclusions: Two-dimensional frontal plane measures show strong relationships to the KAA during the bilateral drop vertical jump.

scholarly journals GAMBARAN KEKUATAN OTOT PADA LANSIA DI BPLU SENJA CERAH PANIKI BAWAH

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Prisilia M. Pinontoan ◽  
Sylvia R. Marunduh ◽  
Herlina I. S. Wungouw
Keyword(s):  
Muscle Strength ◽  
Elderly Women ◽  
Elbow Flexion ◽  
Knee Extension ◽  
Shoulder Abduction ◽  
Elderly Men ◽  
Cross Sectional ◽  
Purposive Sampling ◽  
Shoulder Flexion ◽  
Cross Sectional Design

Abstract: The aim of this study was to find out the profile of muscle strength on elderly at BPLU Senja Cerah Paniki Bawah. This was a descriptive study with cross sectional design. There were 26 respondents who met the inclusion criteria, consisted of 10 elderly men and 16 elderly women. Respondents were selected by using purposive sampling method. The measurements of the muscle strength were done by using 1 RM method while doing elbow flexion, elbow extension, shoulder flexion, shoulder extension, shoulder abduction, knee flexion, knee extension and dorsoflexion. Data were analyzed manually and computerized then presented in tabular form. The result shows that the average muscle strength in elderly men were greater than women and the average muscle strength of respondents that were included in the age group 60-79 years old were greater than those in 80-99 years.Keywords: muscle strength, elderly.1 RMAbstrak: Tujuan dari penelitian ini yaitu untuk mengetahui gambaran kekuatan otot pada Lansia di BPLU Senja Cerah Paniki Bawah. Penelitian ini merupakan peneliltian deskriptif dengan rancangan potong lintang. Responden yang memenuhi kriteria inklusi terdiri dari 26 orang yang terdiri dari 10 orang laki-laki dan 16 orang perempuan. Sampel dipilih menggunakan cara purposive sampling. Kekuatan otot pada lansia diukur dengan menggunakan metode 1 RM yang diukur pada gerakan fleksi siku, ekstensi siku, fleksi bahu, ekstensi bahu, abduksi bahu, fleksi lutut, ekstensi lutut serta dorsofleksi. Data yang sudah didapatkan kemudian dikumpul dan diolah secara manual dan komputerisasi serta disajikan dalam bentuk tabel. Hasil penelitian menunjukkan rerata kekuatan otot responden laki-laki lebih besar dibanding perempuan dan rerata kekuatan responden yang termasuk dalam kelompok umur 60-79 tahun lebih besar dibanding kelompok umur 80-99 tahun.Kata kunci: kekuatan otot, lansia, 1 RM.

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