Throwing Motion Research Articles

The effect of surgery for basal osteoarthritis of the thumb on dart thrower's motion.

This study aimed to identify the effects of basal thumb surgery on the range of dart thrower's motion. Thirteen fresh-frozen cadaveric specimens were placed in a customized jig. Simulated scaphotrapeziotrapezoid joint fusion was carried out on all specimens. Half the specimens then underwent trapeziectomy and the rest had excision of the distal pole of the scaphoid. Simulated scaphotrapeziotrapezoid fusion reduced the range of dart thrower's motion to 89% of the range in the intact wrists, from a mean of 117° to 104°. Although this reduction is not large, it was statistically significant. Simulated trapeziectomy caused a very small increase in dart thrower's motion range compared with the range in the intact wrists. Simulated distal pole of scaphoid excision did not change the range of dart thrower's motion. These results may inform preoperative decisions for surgical management of basal osteoarthritis of the thumb.

Throwing Motion by Flexible Robot Arm using Deep Reinforcement Learning

This paper addresses how to control a robot arm with variable stiffness actuators (VSAs) using deep reinforcement learning. Each VSA has two manipulated variables, target position and stiffness, thereby making learning speed inefficient due to increase of action space. To avoid the increase of action space including deviations of actuators’ stiffness, two policies for position control and stiffness control are explicitly distinguished, instead of end-to-end learning. In a ball throwing motion, the robot therefore learns how to swing its end effector firstly, and later, how to adjust stiffness to accelerate swinging motion. As a result, the robot in a dynamical simulator succeeded in acquiring the ball throwing motion without suffering from huge action space on end-to-end learning.

CT を用いた手関節リバース・ダーツスロー・モーションの3 次元動態解析:─橈骨手根関節と手根中央関節の回転角度と運動方向の検討─

CT を用いた手関節リバース・ダーツスロー・モーションの3 次元動態解析:─橈骨手根関節と手根中央関節の回転角度と運動方向の検討─

Humeral Retroversion and Injury Risk After Proximal Humeral Epiphysiolysis (Little Leaguer’s Shoulder)

Background: The increased humeral retroversion on the dominant side of throwing athletes is thought to result from repetitive throwing motion. Little Leaguer’s shoulder—a rotational stress fracture of the proximal humeral epiphyseal plate—may influence the risk of humeral retroversion and injury of the shoulder or elbow joint. Purpose: To investigate the effect of Little Leaguer’s shoulder on humeral retroversion and the rates of shoulder and elbow injuries. Study Design: Cohort study; Level of evidence, 3. Methods: 10 high school baseball players (average age, 16.6 years; range, 16-18 years) who had experienced Little Leaguer’s shoulder during elementary or junior high school (average age, 12.6 years; range, 11-15 years) were enrolled in the study. As a control group, 22 high school baseball players (average age, 16.9 years; range, 16-18 years) who had never had any shoulder or elbow injury during elementary and junior high school were included. Humeral retroversion on ultrasonographic measurement, shoulder range of motion, and rates of shoulder and elbow injuries were evaluated. Results: Humeral retroversion was significantly greater on the dominant side than on the nondominant side in both players with Little Leaguer’s shoulder (dominant, 104°± 8°; nondominant, 84°± 12°; P < .001) and controls (dominant, 91°± 13°; nondominant, 81°± 10°; P < .001). In the dominant shoulder, humeral retroversion was greater in the Little Leaguer’s shoulder group than in the control group (P = .008). When the effects of humeral retroversion were excluded, maximal external rotation was significantly less in the dominant shoulder than in the nondominant shoulder in the Little Leaguer’s shoulder group (by 11°± 12°, P = .02), whereas no significant difference was found between dominant (110°± 11°) and nondominant (111°± 13°) shoulders in the control group (P = .64). The rates of shoulder and elbow pain were significantly higher in the Little Leaguer’s shoulder group (shoulder pain 80%, elbow pain 70%) than in the control group (shoulder pain 9%, P < .001; elbow pain 32%, P = .04). Conclusion: Humeral retroversion was increased in baseball players without any history of shoulder or elbow injury during elementary and junior high school and was further increased in players who had had Little Leaguer’s shoulder. Increased humeral retroversion after Little Leaguer’s shoulder may be a risk factor for future shoulder or elbow injury.

Does Object Height Affect the Dart Throwing Motion Angle during Seated Activities of Daily Living?

Complex wrist motions are needed to complete various daily activities. Analyzing the multidimensional motion of the wrist is crucial for understanding our functional movement. Several studies have shown that numerous activities of daily livings (ADLs) are performed using an oblique plane of wrist motion from radial-extension to ulnar-flexion, named the Dart Throwing Motion (DTM) plane. To the best of our knowledge, the DTM plane angle performed during ADLs has not been compared between different heights (e.g. table, shoulder and head height), as is common when performing day-to-day tasks. In this study, we compared DTM plane angles when performing different ADLs at three different heights and examined the relationship between DTM plane angles and limb position. We found that height had a significant effect on the DTM plane angles - the mean DTM plane angle was greater at the lower level compared to the mid and higher levels. A significant effect of shoulder orientation on mean DTM plane angles was shown in the sagittal and coronal planes. Our findings support the importance of training daily tasks at different heights during rehabilitation following wrist injuries, in order to explore a large range of DTM angles, to accommodate needs of common ADLs.

Improved Muscle Activity Following Motor Training Without Vision of the Throwing Motion in Baseball Pitchers

Throwing motion without vision has the potential as a training method to improve proprioception by concentrating more on joint movements in throwing. Therefore, the purpose of this study was to suggest a method of training motor sense, which can improve ball velocity and the pitchers’ control (target accuracy). The study population consisted of 20 high school and college baseball players. Rotator cuff and elbow joint muscle activation, ball velocity, and ball accuracy in the stride, arm cocking, acceleration, and deceleration phases during throwing the ball with maximum effort (TBME) with or without vision were measured.

Little Leaguer’s Shoulder Caused Severe Humeral Retroversion: Ultrasonographic Analysis

Objectives:The increased humeral retroversion on the dominant side in throwing athletes is thought to result from repetitive throwing motion. In the previous studies, the degree of increased humeral retroversion was various, suggesting that other factors may affect humeral retroversion. Little Leaguer’s shoulder, which is rotational stress fracture of the proximal humeral epiphyseal plate, may change humeral retroversion. The purpose of this study was to investigate effect of Little Leaguer’s shoulder on humeral retroversion.Methods:Ten high-school baseball players (average, 16.6 years; range, 16 to 18 years), who had had Little Leaguer’s shoulder during elementary or junior high schools (average, 12.6 years; range, 11 to 15 years), were enrolled in the study. As a control group, 22 high-school baseball players (average, 16.9 years; range, 16 to 18 years), who have never had shoulder or elbow pain, were included in this study. Humeral retroversion was ultrasonographically measured on the dominant and non-dominant sides. Humeral retroversion was compared between dominant and non-dominant shoulders with paired t-test. Side-to-side difference in humeral retroversion was compared between Little Leaguer’s shoulders and control group with unpaired t-test.Results:Humeral retroversion was significantly greater on the dominant side than on the non-dominant side in both Little Leaguer’s shoulder (Dominant, 104°±8°; Non-dominant, 84°±12°; P < .001) and control groups (Dominant, 91°±13°; Non-dominant, 81°±10°; P < .001). The side-to-side difference in humeral retroversion in Little Leaguer’s shoulder group (20°±10°) was significantly greater than that in control group (10°±10°, P = .02).Conclusion:Humeral retroversion was increased with repetitive throwing motion without any symptom in the shoulder and elbow joint. Additional increase in humeral retroversion was made when the players had had Little Leaguer’s shoulder in elementary or junior high school.

Rehabilitation and Prehabilitation for Upper Extremity in Throwing Sports: Emphasis on Lacrosse.

Lacrosse imposes multiple simultaneous physical demands during play including throwing and catching a ball while holding a crosse, running, cutting, and jumping. Often, these skills are completed while experiencing contact from another player leading to both on-and-off platform movements. Other motions include defensive blocking and pushing past defenders. Repetitive motions over sustained durations in practice or competition impart mechanical stresses to the shoulder or elbow joints, supportive muscles, and connective tissue. Preparation for lacrosse participation involves bilateral optimization of strength and durability of stabilizer muscles. Passing and shooting skills are encouraged to be equally effective on both sides; therefore, symmetric strength and flexibility are vital for prehabilitation and rehabilitation efforts. This article will: 1) provide insights on the upper-extremity musculoskeletal demands of lacrosse and related sports with similar throwing motion and 2) describe prehabilitation and rehabilitation methods that improve athlete durability and reduce likelihood of upper-extremity injury.

Does physical education foster skill acquisition in novices from childhood to adolescence?

The goal of this study was to examine age and gender-related differences in quantitative and qualitative throwing performances of novices across a lifespan six to 16 years of age. Quantitative and qualitative throwing performances of 110 participants were evaluated in a controlled setting. The overall throwing movement was also sub divided into five essential movement characteristics: trunk, forearm, humerus, stepping, and backswing actions (Halverson &amp; Roberton, 1984).The participants had to throw as hard and accurate as possible aiming a target on the wall. Each trial was videotaped for qualitative data analysis which has been conducted by using a modified component approach. The present findings show that across the three age bands, novices stagnated on a low level of movement development. Also, gender differences in the development of the throwing movement characteristics were found for the age band childhood and in some features gender differences were sustained throughout the examined age bands until adolescence. Within the novices, higher performance values in favour of male were found during childhood for trunk, forearm, and backswing actions, and in the quantitative performance-measure. Within the pubescence, gender differences existed only for trunk action and within the adolescence only for backswing action. There were no progress in throwing movement characteristics between the various levels of motor development. Thus, no improvement of the throwing movement quality and accuracy (quantity) could be recognised, which is calling for improvements in physical education. Compared with athletes in the same age, in contrast a study by Gromeier, Koester, and Schack (2017) show that with increasing age, qualitative performance of male and female athletes improves and furthermore it can be seen that male and female athletes demonstrated similar movement patterns in the main function phase. That raises questions concerns issue of physical education.

A Clinician's Guide to Analysis of the Pitching Motion.

This review examines recent literature regarding analysis of the throwing motion in baseball players and how modern technology may be used to predict or prevent injury. Proper throwing technique is vitally important to prevent injury and it is easier to correct poor mechanics prior to foot strike. Recent findings suggest that the inverted-W position may not lead to an increased risk of injury, but incorrect trunk or pelvis rotation does. Three-dimensional motion analysis in a laboratory setting is most commonly used to evaluate the throwing motion, but it does not allow for assessment in real game scenarios. Wearable monitors allow for this and have proven to reliably assess pitching workload, kinematics, and kinetics. Injuries in youth baseball pitchers have increased along with the trend towards more single sport specialization. To prevent injury, assessment of a pitcher's throwing motion should be performed early to prevent development of poor mechanics. Classically, three-dimensional motion analysis has been used to evaluate throwing mechanics and is considered the gold standard. Newer technology, such as wearable monitors, may provide an alternative and allow for assessment during actual competition.

Skeleton-based comparison of throwing motion for handball players

The main goal of this work is to design an automated solution based on RGB-D data for quantitative analysis, perceptible evaluation and comparison of handball player’s performance. To that end, we introduced a new RGB-D dataset that can be used for an objective comparison and evaluation of handball player’s performance during throws. We filmed 62 handball players (44 beginners and 18 experts), who performed the same type of action, using a Kinect V2 sensor that provides RGB data, depth data and skeletons. Moreover, using skeleton data simulating 3D joint connections, we examined the main angles responsible for throwing performance in order to analyze individual skills of handball players (beginners against model and experts) relatively to throw actions. The comparison was performed statically (using only one frame) as well as dynamically during the entire throwing action. In particular, given the temporal sequence of 25 joints of each handball player, we adopted the dynamic time warping technique to compare the throwing motion between two athletes. The obtained results were found to be promising. Thus, the suggested markless solution would help handball coaches to optimize beginners’ movements during throwing actions.

초등학교 학생들의 농구 자유투 동작에 대한 근전도 분석

초등학교 학생들의 농구 자유투 동작에 대한 근전도 분석

Dart thrower's motion and the injured scapholunate interosseous ligament: A scoping review of studies examining motion, orthoses, and rehabilitation

Study DesignScoping review. IntroductionDart thrower's motion (DTM) of the wrist primarily arises from the midcarpal joint, and minimizes stress to the scapholunate interosseous ligament (SLIL). After SLIL injury or surgery, early controlled DTM may reduce the effects of prolonged immobilization, while protecting SLIL integrity. Purpose of the StudyTo summarize the literature on the effects of DTM on the injured and surgically repaired SLIL and the extent to which various DTM orthotic designs promote SLIL recovery. MethodsA systematic literature search was conducted within 6 databases for articles published between 2003 and March 2018. Eligible studies examined DTM in the context of SLIL injury or repair. Relevant data were extracted by 2 independent reviewers. ResultsOf 425 identified articles, 15 were eligible for inclusion. Five biomechanical studies examined the influence of DTM on the injured SLIL, whereas 5 articles described DTM orthotic designs. Also included were five articles that reported outcomes when DTM was used in the rehabilitation protocol. DiscussionThe included studies suggest limiting end ranges of DTM in the injured/repaired SLIL, while blocking orthogonal plane movements. Custom orthotic designs may accomplish this goal. DTM has been used in comprehensive therapy programs in small case studies reporting short-term and intermediate clinical outcomes. ConclusionsCaution should be exercised with using DTM on the torn SLIL as gap increases, particularly at the end-range motion. Orthosis designs have potential to limit this motion to midrange, while allowing early movement. Further high-level research is needed to understand the influence of DTM on injured and postsurgical populations.

The primacy of rhythm: how discrete actions merge into a stable rhythmic pattern.

This study examined how humans spontaneously merge a sequence of discrete actions into a rhythmic pattern, even when periodicity is not required. Two experiments used a virtual throwing task, in which subjects performed a long sequence of discrete throwing movements, aiming to hit a virtual target. In experiment 1, subjects performed the task for 11 sessions. Although there was no instruction to perform rhythmically, the variability of the interthrow intervals decreased to a level comparable to that of synchronizing with a metronome; furthermore, dwell times shortened or even disappeared with practice. Floquet multipliers and decreasing variability of the arm trajectories estimated in state space indicated an increasing degree of dynamic stability. Subjects who achieved a higher level of periodicity and stability also displayed higher accuracy in the throwing task. To directly test whether rhythmicity affected performance, experiment 2 disrupted the evolving continuity and periodicity by enforcing a pause between successive throws. This discrete group performed significantly worse and with higher variability in their arm trajectories than the self-paced group. These findings are discussed in the context of previous neuroimaging results showing that rhythmic movements involve significantly fewer cortical and subcortical activations than discrete movements and therefore may pose a computationally more parsimonious solution. Such emerging stable rhythms in neuromotor subsystems may serve as building blocks or dynamic primitives for complex actions. The tendency for humans to spontaneously fall into a rhythm in voluntary movements is consistent with the ubiquity of rhythms at all levels of the physiological system. NEW & NOTEWORTHY When performing a series of throws to hit a target, humans spontaneously merged successive actions into a continuous approximately periodic pattern. The degree of rhythmicity and stability correlated with hitting accuracy. Enforcing irregular pauses between throws to disrupt the rhythm deteriorated performance. Stable rhythmic patterns may simplify control of movement and serve as dynamic primitives for more complex actions. This observation reveals that biological systems tend to exhibit rhythmic behavior consistent with a plethora of physiological processes.

Simple real-time cloud-connected actigraphy solution for monitoring patient activity using mobile phones

Rehabilitation patient activity is not typically monitored in real-time due to lack of suitable actigraphy devices. We present an open-source actigraphy system with integrated real-time cloud data storage based on mobile phones for potential use in patient activity monitoring and quantitation. An iPhone program was created to stream an actigraphy score to a cloud data storage service, Adafruit IO, in real-time. The actigraphy score is calculated as vector magnitude from three-axis accelerometer data at 2.5 second epochs. Actigraphy data was successfully streamed to the cloud storage and visualization platform at up to 30 Hertz, with 60 Hertz possible at a higher cost tier. Data was represented as decimal with two significant digits of precision. No movement at all is normalized to 0. Maximum vector magnitude with moderate walking was 0.39. Maximum vector magnitude with jogging was 1.02 Maximum vector magnitude with the phone in the hand during a throwing motion was 5.47. iOS reported energy draw was low (level 1 out of 20). In summary, we present an open-source design for a simple and inexpensive real-time cloud-connected actigraphy system for rehabilitation patients. Alternative platforms and devices are discussed, as are security and cost implications The widespread use of mobile devices and the iOS platform, with optional integration of global positioning coordinates and other phone data, are advantageous compared to purpose-built existing actigraphy solutions.

Changes in lower extremity function and pitching performance with increasing numbers of pitches in baseball pitchers.

Compared to upper extremity function, the changes in lower extremity function with increasing numbers of pitches have not fully been investigated in baseball pitchers. In addition, little is known about the correlation between lower extremity function and pitching performance. The purpose of this study was to evaluate the effect of fatigue on lower extremity function and pitching performance in a simulated baseball game. Eighteen collegiate baseball pitchers threw 117 pitches in 9 innings (13 pitches per inning) with 5-min rest between innings at an official pitching distance in a simulated game. Isometric hip muscle strength (abduction and adduction) and squat jump performance (height, mean/peak power, and mean/peak velocity) were measured before and after the game. The mean ball velocity and pitching accuracy were assessed per inning. Ball velocity significantly decreased in the 7th (P=0.026) and 9th (P=0.001) innings compared to the 1st inning, but pitching accuracy did not change significantly. Hip abduction (P=0.009) and adduction (P=0.001) strength significantly decreased after the game, but squat jump performance did not significantly change before and after the game. A significant correlation between decreased ball velocity in the 9th inning and decreased hip adduction strength was found (P=0.011, r=0.583). Our findings suggest that hip abduction and adduction strength are susceptible to fatigue owing to repetitive throwing motions and that hip adduction strength, especially, is an important physical fitness factor for maintaining ball velocity during a game in baseball pitchers.

Clinical measurement of the dart throwing motion of the wrist: variability, accuracy and correction.

Despite being functionally important, the dart throwing motion is difficult to assess accurately through goniometry. The objectives of this study were to describe a method for reliably quantifying the dart throwing motion using goniometric measurements within a healthy population. Wrist kinematics of 24 healthy participants were assessed using goniometry and optical motion tracking. Three wrist angles were measured at the starting and ending points of the motion: flexion–extension, radial–ulnar deviation and dart throwing motion angle. The orientation of the dart throwing motion plane relative to the flexion–extension axis ranged between 28° and 57° among the tested population. Plane orientations derived from optical motion capture differed from those calculated through goniometry by 25°. An equation to correct the estimation of the plane from goniometry measurements was derived. This was applied and differences in the orientation of the plane were reduced to non-significant levels, enabling the dart throwing motion to be measured using goniometry alone.

User surveys support designing a prosthetic wrist that incorporates the Dart Thrower’s Motion

Aim: Prosthetic devices are not meeting the needs of people with upper limb amputations. Due to controlsidelimitations, prosthetic wrists cannot yet be fully articulated. This study sought to determine which wrist motions users felt were most important for completing activities of daily living. We specifically invstigated whether adding a combinationof flexion and deviation known as the Dart Thrower's Motion to a prosthetic wrist would help improve functionality.Methods: Fifteen participants with a trans-radial amputation, aged 25–64 years, who use a prosthesis completed an online survey and answered interview questions to determine which types of tasks pose particular challenges. Participants were asked what kinds of improvements they would like to see in a new prosthesis. A subset of five participants were interviewed in-depth to provide further information about difficulties they face using their device.Results: The survey showed that participants had difficulty performing activities of daily living that involve a combination of wrist flexion and deviation known as the “Dart Throwers Motion”. Interview responses confirmed that users have difficulty performing these tasks, especially those that require tools. Additionally, users said that they were more interested in having flexion and deviation than rotation in a prosthetic wrist.Conclusion: This research indicates that including the Dart Thrower's Motion in future designs of prosthetic wrists would improve these devices and people with upper limb amputations would be excited to see this improvement in their devices.Implications for Rehabilitation• Over one third of people with upper limb amputations do not use a prosthesis because prosthetic devices do not meet their needs.• The number of motions possible in state of the art prosthetic devices is limited by the small number of control sites available.• The Dart Thrower?s Motion is a wrist motion used for many activities of daily living but unavailable in commercial prosthetics leading many prosthetics users to have difficulty with these tasks.• Prosthetic use, and therefore quality of life, could be improved by including the Dart Thrower’s Motion in a prosthesis.

FUNCTIONAL AND KINEMATIC ANALYSIS OF A WRIST RADIAL HEMIARTHROPLASTY DESIGN

Purpose: A biomechanical functional assessment was performed on a newly designed wrist hemiarthroplasty implant with aimed to identifying differences between the native wrist and wrist following the hemiarthroplasty procedure with [Formula: see text] and without a proximal row carpectomy (Hemi). Methods: Six cadaveric wrists were mounted on a custom testing fixture and underwent a series of functional tests to investigate differences in range of motion, muscles moment arms, and axis of rotation between the intact and post-operative wrists. The tested movements included manually-driven flexion-extension, radial-ulnar deviation, dart throwers motion, and circumduction. Results: The only significant change in range of motion was a decrease in flexion between the intact [Formula: see text] and both the Hemi [Formula: see text] and [Formula: see text] [Formula: see text] conditions. Minor differences in the mean position and variability of the axis of rotation’s piercing point were identified. A statistically significant decrease in the flexion moment arm of the flexor carpi radialis was identified between the intact ([Formula: see text][Formula: see text]mm) and [Formula: see text] ([Formula: see text][Formula: see text]mm) conditions. Statistically significant decreases were also identified in the radial deviation moment arms of the extensor carpi radialis brevis’ between the intact ([Formula: see text][Formula: see text]mm) and [Formula: see text] ([Formula: see text][Formula: see text]mm) conditions and the flexor carpi radialis’ between the intact ([Formula: see text][Formula: see text]mm) and Hemi ([Formula: see text][Formula: see text]mm) conditions as well as in the ulnar deviation moment arm of the extensor carpi ulnaris between the intact ([Formula: see text][Formula: see text]mm) and Hemi ([Formula: see text][Formula: see text]mm) conditions. Conclusions: While some statistically significant functional changes were identified between the native and hemiarthroplasty wrist, the findings suggest that post-operative function is equally acceptable in hemiarthroplasty with and without resection of the proximal carpal row.

Lower shoulder abduction during throwing motion may cause forceful internal impingement and decreased anterior stability

Internal impingement and decreased anterior stability, which result from shoulder capsular loosening, are common shoulder pathologies in throwing athletes. The purpose of this study was to assess the effect of shoulder abduction angle on shoulder internal impingement and anterior shoulder stability during the simulated throwing motion. Eight cadaveric shoulders were tested by simulating the late-cocking and acceleration phases of the throwing motion for intact and thrower's shoulder conditions. The maximal glenohumeral external rotation, anterior translation, location of the rotator cuff insertion with respect to the glenoid, length and site of internal impingement, and glenohumeral contact pressure were measured. All data were compared between shoulder abduction angles of 80°, 90°, and 100°. Decreasing shoulder abduction in the simulated late-cocking phase shifted the humeral head posteriorly (P < .03) and superiorly (P < .001), decreasing the total internal impingement area between the greater tuberosity and glenoid (P = .04) and increasing the glenohumeral contact pressure during internal impingement (P = .02). In the simulated acceleration phase, anterior glenohumeral translation significantly increased as the shoulder abduction angle decreased (P < .001). Decreasing shoulder abduction significantly increased the contact pressure during internal impingement in the simulated late-cocking phase of the throwing motion. During the simulated acceleration phase of the throwing motion, anterior glenohumeral translation significantly increased as shoulder abduction decreased.