Search Results (35)

Background/Objectives: In overhead throwing sports such as baseball and softball, upper extremity injuries are prevalent at both collegiate and high school levels. Currently, there is no universal assessment protocol to identify athletes at risk for injury or to determine their readiness to return to sport. This study aimed to investigate the relationship between shoulder internal rotation (IR) and external rotation (ER) isometric strength in a throwing position and three upper extremity functional tests among collegiate baseball players. It was hypothesized that there would not be significant correlations between shoulder IR and ER peak isometric force and the following functional assessments: the Upper Quarter Y Balance Test (YBT-UQ), seated single-arm shot put, and Closed Kinematic Chain Upper Extremity Strength Test (CKCUEST). Methods: Forty healthy collegiate baseball players volunteered for the study. After completing a self-guided warm-up, participants performed bilateral isometric shoulder IR and ER strength tests at 90 degrees of shoulder abduction and elbow flexion, followed by the three functional tests in random order. Relationships were analyzed using Pearson’s correlation coefficients (r), with a significance level set at p < 0.05. Results: Correlations were generally low, ranging from r = 0.001 to r = 0.551. Significant correlations were observed between the CKCUEST and dominant IR strength (r = 0.345, p = 0.031), dominant ER strength (r = 0.407, p = 0.010), and non-dominant ER strength (r = 0.551, p < 0.001). Additionally, a significant correlation was found between the dominant ER/IR strength ratio and the dominant arm superolateral reach on the YBT-UQ (r = −0.352, p = 0.026). No significant correlations were identified between isometric shoulder strength and the single-arm shot put. Conclusions: Most correlations were low to moderate, and only significant correlations between shoulder rotation isometric strength and one direction of the YBT-UQ and the CKCUEST were observed. Thus, shoulder rotation strength in a position similar to the cocking phase of overhead throwing may be valuable for return-to-sport criteria and injury screening for overhead athletes. However, further research is needed to validate these findings. Full article

The main objective of this study was to analyze the physical fitness parameters of young competitive padel players, compare potential differences between male and female players, and examine the relationships among various physical fitness variables in this population. The sample consisted of 18 players (10 boys and 8 girls) aged between 12 and 16 years old belonging to the Technification program for minors of the Valencian Padel Federation. The players completed a test battery that consisted of different tests: CMJ jump, internal and external shoulder rotator strength, manual dynamometry, functional upper body strength (forehand throw, backhand throw, bilateral overhead throw, and serve throw), smash speed, 5 × 10 m agility test, and tapas test. Data analysis was carried out with SPSS software for Windows (Version 25.0, IBM Corp., Armonk, NY, USA). The results showed that the boys obtained significantly higher values in the tests of dynamometry, speed, agility (tapas test), and throws (forehand, backhand, serve, and over the head), and the girls obtained significantly higher values in the test of shoulder external rotation (non-dominant). At the same time, the force variables were significantly and positively related to each other. The CMJ values are also significantly and positively correlated with the variables of shoulder rotation, sprint speed, and medicine ball throws. Regarding agility, significant and positive correlations were found in the tapas test. However, the 5 × 10 m test showed negative and significant correlations with some variables. It has been observed that the results obtained coincide with the results found in other studies carried out with players of the same age in other sports, such as tennis and soccer. Full article

Background/Objectives: The repetitive overhead throwing of baseball stresses the posterior shoulder, including the rotator cuff and capsule, causing stiffness, tissue thickening, and dysfunction. Previous studies on collegiate baseball players have linked these changes to glenohumeral internal rotation deficits, pain, and injuries. However, these studies primarily used acoustic radiation force impulse-based shear wave elastography (SWE), which has limitations, including tissue heating and lack of portability. The acute effects of pitching on infraspinatus (ISP) muscle elasticity in high school pitchers remain unclear. Therefore, this study aimed to evaluate the acute impact of pitching on ISP muscle elasticity in high school baseball pitchers using continuous SWE (C-SWE), which is a safer and more portable method. The relationship between ISP muscle elasticity and pitching load was also examined. Methods: ISP muscle shear wave velocity (SWV), shoulder range of motion, and strength were evaluated in high school baseball pitchers. The participants were categorized into pitching and non-pitching groups based on whether they pitched with full effort on the day of their medical checkup. C-SWE was used to assess ISP muscle elasticity. Results: The pitching group had considerably higher ISP muscle SWV on the dominant side than the non-pitching group (p = 0.008). A significant positive correlation was observed between pitch and ISP muscle SWV (r = 0.467, p = 0.003). Conclusions: Repetitive pitching acutely increases ISP muscle stiffness in high school pitchers, contributing to posterior shoulder tightness. C-SWE is a safe and practical method for assessing tissue elasticity and developing injury prevention strategies. Full article

(1) Background: Shoulder pathologies are mostly found in overhead sports. Many risk factors have been identified, in particular a deficit in the kinetic chain. The aim of this review was to find out whether prevention by strengthening the kinetic chain can have an impact on the rate of shoulder injury in overhead pitching athletes. (2) Methods: A systematic review of the literature was carried out, including studies on the role of the kinetic chain in the prevention of overhead athletes. The studies used were works published over the last 10 years searched on PubMed, Cochrane Library, PEDro and Science Direct. They were also analyzed by methodological quality scales: the PEDro scale and the Newcastle–Ottawa scale. (3) Results: Eight studies met the inclusion criteria. The studies analyzed revealed a significant correlation between the use of the kinetic chain and the prevention of shoulder injuries, associating factors such as muscle strength, physical performance in tests (CMJ, FMS), static and dynamic balance and the ability to transfer energy from the lower to the upper body. (4) Conclusions: It is important to integrate core stability work and lower limb strengthening to minimize excessive stress on the shoulder complex, while optimizing force production and performance. Full article

The strength of the shoulder musculature involved with internal rotation and arm extension plays an important role in the overhead throwing motion for baseball athletes, both for throwing-related performance and injury risk. The maintenance of shoulder strength is a high priority for baseball athletes throughout a season; however, little is known in regards to the expected changes in strength throughout a season. To examine pre-post changes in shoulder strength, lower body power, and body composition among collegiate baseball players after the completion of a summer baseball league season. Amateur baseball players (n = 12; age: 20.9 ± 1.0 years.; height: 181.6 ± 5.6 cm; body mass: 86.4 ± 11.1 kg; BMI: 26.0 ± 2.6 kg/m²) participated in the current study. Pre- and post-competitive season, the participants completed shoulder strength assessments and body composition and countermovement vertical jump (CMJ) tests. An upper-body isometric test (athletic shoulder [ASH] test) was used to evaluate shoulder strength for each arm. Each subject completed maximal isometric contractions for both the throwing and non-throwing arms at four separate angles of abduction (180°, ‘I’; 135°, ‘Y’; 90°, ‘T’; and −180°, ‘A’) while lying in a prone position. For shoulder strength, the primary dependent variable of interest was a composite measure that represented the average of the forces produced across all four positions of the ASH test (I, Y, T, A). For the ASH test composite measure, there was a trend toward a significant arm-by-time interaction effect (p = 0.08), as shoulder strength decreased by 9.03% for the throwing arm (ES = 0.72; 95% CI = [−0.27, −0.01]), compared to only 2.03% for the non-throwing arm (ES = 0.15; 95% CI = [−0.16, 0.09]), over the course of the season. The main effects of time (p = 0.16) and arm (p = 0.58) were not significant for the ASH test composite measure. There was no relationship between lower body power and throwing arm strength at baseline (r = 0.20, p = 0.56), and only a non-significant weak relationship at post-test (r = 0.28, p = 0.41). Throughout a season, baseball players may experience reductions in shoulder strength of the throwing arm with minimal changes in shoulder strength in the non-throwing arm. Full article

Throwing performance is a critical aspect of sports, particularly in overhead activities, necessitating reliable assessment methods. This study explores the test–retest reliability of throwing performance metrics measured by the 1080 Sprint, a robotic device integrating linear position technology and an electric motor. Specifically focusing on professional volleyball athletes with scapular dyskinesis, the study draws data from a previously published investigation on the impact of mirror cross exercise. Thirty-nine athletes were recruited, aged 21.9 ± 3.6 years, height 1.79 ± 0.3 m weight 68.5 ± 19.8 kg, and body mass index 21.3 ± 3.2 kg/m², meeting stringent inclusion criteria. One-sample t-tests indicated no statistically significant differences between test–retest trials. The study revealed excellent reliability of the 1080 Sprint, with intraclass correlation coefficient (ICC) values exceeding 0.99 for all metrics, including speed, force, and power. The standard error of measurement (SEM) calculation revealed that the Sprint 1080 motorized resistance device demonstrates high precision in measuring throwing performance. Bland and Altman plots indicated minimal systematic bias across all metrics, encompassing speed, force, and power. The provision of the minimum detectable change (MDC) for each variable of the Sprint 1080 motorized resistance device offers coaches a valuable tool to identify performance improvements in volleyball athletes. In conclusion, the present study shows that the 1080 Sprint is valid and reliable for measuring throwing performance in volleyball athletes for monitoring purposes. Full article

Objectives: The objective is to compare stiffness changes around the shoulder muscles between pitchers and position players after throwing overhead using shear wave elastography (SWE) in relation to throwing motion analysis and muscle strength. Methods: A total of 32 male college baseball players (12 pitchers and 20 position players) were observed throwing 20 times, and SWE was performed to evaluate 13 shoulder muscle items—tendons (supraspinatus, infraspinatus, subscapularis, and teres minor), muscles (supraspinatus, infraspinatus [transverse and oblique part], teres minor, lower trapezius, latissimus dorsi, and pectoralis minor), and capsules (posterior and posteroinferior). Motion analysis was used to assess elbow torque, forearm angle, forearm rotation speed, and maximum external rotation angle of the shoulder. Muscle strength was measured using a dynamometer for abduction, internal/external rotation of the shoulder at an abduction of 0°, internal/external rotation of the shoulder at an abduction of 90°, and internal/external rotation of shoulder at a flexion of 90°. Results: In the pitcher group, SWE values for the teres minor muscle and latissimus dorsi muscle increased significantly after throwing. In the position player group, SWE values for the teres minor muscle significantly increased, and SWE values of the pectoralis minor muscle decreased after throwing. In the pitcher group, positive correlations were found between the teres minor muscle and forearm rotation speed and between the latissimus dorsi muscle and forearm angle. No significant difference was found in muscle strength after throwing in any of the groups. Conclusions: Stiffness changes occurred after throwing and were related to the motion analysis, but the regions in which stiffness occurred varied between pitchers and position players. Full article

In tennis, the serve plays a key role in determining the success of a player. The speed of a serve is influenced by a multitude of interconnected skills and abilities. The objective of this study was to establish the correlation between the explosive strength of the throwing type, the grip strength and flexibility of the arms, and the shoulder girdle with the serve speed in young female tennis players. Additionally, the study aimed to develop a regression model that accurately predicts the serve speed by analyzing the interplay among these variables. The study was carried out on a group of 20 tennis players, who had an average age of 13.10 ± 0.74 years. Additionally, their height was recorded as 165.70 ± 4.90 cm, and their body mass was measured at 51.45 ± 5.84 kg. To assess the motor abilities of the upper extremities, four tests were used that aimed to measure the explosive strength of the throwing type; one test was for the strength of the hand and forearm muscles, and one test was for the flexibility of the arms and shoulder girdle. Of all the variables examined, the medicine ball throw shot put (MBTSP) (r = 0.75), overhead medicine ball throw (OMBT) (r = 0.70), and grip strength (GS) (r = 0.71) displayed a notable correlation with serve speed (p < 0.05). The results obtained from the multiple regression analysis indicate that the combination of selected predictors (MBTSP—medicine ball throw shot put, OMBT—overhead medicine ball throw and GS—grip strength) explained 75% of the variability in serve speed. Significantly, MBTSP surfaced as the predominant predictor, autonomously elucidating 51% of the variability in serve speed. The importance of improving the analyzed motor skills of young female tennis players to enhance their serve in terms of speed is emphasized by the findings of this research. Full article

Water polo players’ shoulders are exposed to repeated overhead and throwing motions as well as direct and indirect traumas. Shoulder injuries account for over half of all injuries sustained by water polo players. This is a monocentric descriptive epidemiological study on the clinical and radiological presentation of a consecutive series of water polo players from January 2002 to September 2022. All patients underwent clinical and physical examinations and an MRI arthrogram. A total of 92 water polo players were included in this study. Fifty-three patients (57.6%) reported at least one previous shoulder instability episode; 100% of patients in this group were diagnosed with a capsulolabral complex lesion, and 88.7% of these players complained of subjective symptoms of shoulder instability (RR: 4.4). A total of 39 out of 92 patients (42.4%) did not report previous shoulder dislocation episodes; the mean age at presentation in this group was significantly higher than the mean age of the patients who experienced previous instability episodes (p < 0.01), and the throwing arm was affected in 79.5% of patients (RR = 1.41). Full article

Moose herd–train collisions represent one of the potential hazards that railway operations must contend with, making the assessment of passive train safety in such scenarios a crucial concern. This study analyzes the responses of bullet trains colliding with moose herds and investigates the influence of various factors under these conditions. To achieve this goal, a multibody (MB) model was developed using the MADYMO platform. The displacement of the moose’s center of gravity (CG) was employed to assess the safety boundaries, while the relative positions between the wheels and rails were used to evaluate the risk of derailment. The findings revealed that the collision forces exhibited multi-peak characteristics that were subsequently transmitted to the wheel–rail contact system, resulting in disturbances in the relative positions of the wheels and rails. However, these disturbances did not reach a level that would induce train derailment. Furthermore, larger moose herds exhibited higher throw heights, although these heights remained within safe limits and did not pose a threat to overhead lines. The primary safety risk in moose–train collisions stemmed from secondary collisions involving moose that had fallen onto the tracks and oncoming trains. This study offers valuable insights for enhancing the operational safety of high-speed trains and safeguarding wildlife along railway corridors. Full article

The purpose of our study was to determine differences in adaptative and injury patterns in the elbow related to valgus extension overload (VEO) in overhead throwing athletes by age. A total of 86 overhead throwing athletes and 23 controls underwent MRI or MR arthrography (MRA) of the elbow. Throwing athletes were divided by age into three groups: ≤16 years (26 subjects), 17–19 years (25 subjects), and ≥20 years (35 subjects). Consensus interpretation of each MRI was performed, with measurements of ulnar collateral ligament (UCL) thickness and subchondral sclerosis at the radial head, humeral trochlea, and olecranon process. A higher frequency of apophyseal and stress injuries was seen in adolescent athletes and increased incidence of soft tissue injuries was observed in older athletes. Early adaptive and degenerative changes were observed with high frequency independent of age. Significant differences were observed between athletes and controls for UCL thickness (p < 0.001) and subchondral sclerosis at the radial head (p < 0.001), humeral trochlea (p < 0.001), and olecranon process (p < 0.001). Significant differences based on athlete age were observed for UCL thickness (p < 0.001) and subchondral sclerosis at the olecranon process (p = 0.002). Our study highlights differences in anatomic adaptations related to VEO at the elbow between overhead throwing athletes and control subjects, as well as across age in throwing athletes. Full article

Kinetic chains (KCs) are primarily affected by the load of different activities that recruit muscles from different regions. We explored the effects of strengthening exercises on KCs through muscle activation. Four databases were searched from 1990 to 2019. The muscles of each KC, their surface electromyography (sEMG), and the exercises conducted were reported. We found 36 studies that presented muscle activation using the percent (%) maximal voluntary isometric contraction (MVIC) or average sEMG for nine KCs in different regions. The % MVIC is presented as the following four categories: low (≤20%), moderate (21~40%), high (41~60%), and very high (>60%). Only four studies mentioned muscle activation in more than three KCs, while the remaining studies reported inconsistent sEMG processing, lacked normalization, and muscle activation in one or two KCs. The roles of stabilizers and the base of support in overhead throwing mobility using balance exercises were examined, and the concentric phase of chin-up and lat pull-down activated the entire KC by recruiting multiple muscles. Also, deep-water running was shown to prevent the risk of falls and enhance balance and stability. In addition, low-load trunk rotations improved the muscles of the back and external oblique activation. Based on this study’s findings, closed-chain exercises activate more groups of muscles in a kinetic chain than open-chain exercises. However, no closed or open chain exercise can activate optimal KCs. Full article

The aim of the study was to assess the effects of 8 weeks of resistance training using a flywheel device applied to upper limbs, compared to traditional isotonic training, on strength and shot precision in tennis. Twenty-seven elite senior tennis players (age: 55.78 ± 2.69) were randomly divided into an experimental group (EG) using flywheel devices (n = 13) and a control group (CG) performing isotonic training (n = 14). The EG program included forehand, backhand, and one-handed shoulder press movements, while the CG performed seven resistance exercises on isotonic machines. A similar workout intensity was ensured using the Borg’s CR-10 scale. The assessment included a 30s arm curl test, a medicine ball throw test, and forehand/backhand/overhead shot precision tests. A significant time effect was found in the 30s arm curl test for the EG (F_(1,25) = 13.09; p = 0.001), along with a time * group interaction (F_(1,25) = 5.21; p = 0.031). A significant group difference was observed in the forehand shot precision test, where the EG achieved better scores than the CG and significant interaction time * group (F_(1,25) = 8.35; p = 0.008). In the shot backhand precision test, a significant effect of time (F_(1,25) = 5.01; p = 0.034) and significant time * group interaction were found (F_(1,25) = 4.50; p = 0.044), but there was no significant difference between groups. Resistance training with flywheel devices has shown potential in improving tennis performance. Applying overload to specific athletic movements during both concentric and eccentric phases in the EG has shown enhanced strength and neuromuscular coordination in relation to shot precision, thereby enabling simultaneous improvements in both conditioning and the technical aspects of fundamental tennis shots. Full article

Nowadays, malware remains a significant threat to the current cyberspace. More seriously, malware authors frequently use metamorphic techniques to create numerous variants, which throws malware researchers a heavy burden. Being able to classify these metamorphic malware samples into their corresponding families could accelerate the malware analysis task efficiently. Based on our comprehensive analysis, these variants are usually implemented by making changes to their assembly instruction sequences to a certain extent. Motivated by this finding, we present a streamlined and efficient framework of malware family classification named MalSEF, which leverages sampling and parallel processing to efficiently and effectively classify the vast number of metamorphic malware variants. At first, it attenuates the complexity of feature engineering by extracting a small portion of representative samples from the entire dataset and establishing a simple feature vector based on the Opcode sequences; then, it generates the feature matrix and conducts the classification task in parallel with collaboration utilizing multiple cores and a proactive recommendation scheme. At last, its practicality is strengthened to cope with the large volume of diversified malware variants based on common computing platforms. Our comprehensive experiments conducted on the Kaggle malware dataset demonstrate that MalSEF achieves a classification accuracy of up to 98.53% and reduces time overhead by 37.60% compared to the serial processing procedure. Full article

Bat swing velocity (BSV) is an imperative element of a successful baseball hitting performance. This study aimed to investigate the anthropometric and physiological variables associated with BSV and explore strength and conditioning programs to increase BSV in collegiate baseball players. Seventy-eight collegiate baseball players (mean age ± SD, 19.4 ± 1.0 years) participated in this study. Maximum BSV (km/h) was measured using Blast Baseball (Blast Motion Inc., Carlsbad, CA, USA). The anthropometric and physiological variables measured were height, body mass, lean body mass, grip strength, back muscle strength, the 30 m sprint, standing long jump, and backward overhead medicine ball throwing. Analysis using Pearson’s product-moment correlation coefficient showed a weak but significant positive correlation between all anthropometric measurements to BSV. Significant relationships existed between physiological variables of hand grip, back muscle strength, and backward overhead medicine ball throwing, but not the standing long jump and 30 m sprint. These data show that BSV is related to anthropometric and physiological variables, particularly upper and lower body strength and full-body explosive power. Based on the results of this study, we designed examples of sound training programs to increase BSV. Strength and conditioning coaches may want to consider using this information when designing a training program for collegiate baseball players. Full article