Swing Speed Research Articles

Correlation Between Muscle Strength, Swing Speed, Batting Statistics, and Body Composition Parameters in High School Baseball Players: A Retrospective Observational Study.

Suzuki, K, Mizoguchi, Y, Kimura, F, Fujisaki, K, Yokoyama, D, Hall, T, and Akasaka, K. Correlation between muscle strength, swing speed, batting statistics, and body composition parameters in high school baseball players: a retrospective observational study. J Strength Cond Res XX(X): 000-000, 2024-Body composition has emerged as a pivotal factor influencing baseball player performance. The purpose of this study was to examine the relationships between muscle strength, swing speed, batting statistics, and body composition in high school baseball players. This retrospective study evaluated 29 high school baseball players included critical parameters related to body composition (body fat percentage, lean body mass [LBM], fat mass index [FMI], and fat-free mass index [FFMI]), muscle strength (bench press, squat, deadlift), batting statistics (batting average, on-base percentage, slugging percentage, on-base plus slugging), and swing speed. These metrics were gathered using a body composition analyzer (Omron HBF-701; Omron Healthcare Co., Kyoto, Japan). After the correlation analysis with body composition, a subsequent multivariate analysis was conducted. Multivariate regression analysis identified LBM (p < 0.05, p < 0.01) as a significant predictor for bench press and swing speed, FFMI for squat (p < 0.01), and FMI for deadlift (p < 0.05). No significant association was found between body composition and batting statistics. Lean body mass has been identified as an important contributing factor to swing speed, suggesting the need for body composition management among high school baseball players and coaches to enhance performance and functionality. However, no association was found between batting statistics and body composition. Therefore, it is suggested that high school baseball players prioritize the development of technical skills over swing speed and muscle strength to improve batting statistics.

Kinematic differences between female national and provincial athletes in the tennis serve.

Tennis, the second-largest ball game in the world, has a particularly wide audience. To date, little research has been conducted on the biomechanics of female serves. The purpose of this study was to capture the key moments by using 1,000 frames/s high-speed video analysis, to analyze the kinematics of the serving techniques of national athletes and provincial athletes, to determine the differences between the two levels of athletes, and to provide theoretical references for the improvement of scientific training level. Ten female athletes were selected as participants for this study, five of whom are national athletes, and the other are provincial athletes. Three-dimensional filming techniques were employed to capture videos of the first and second serve techniques. Simi Motion was applied to obtain the 3D kinematic data. Statistical analyses were performed using IBM SPSS Statistics 27.0, and Mann-Whitney U tests were conducted to determine differences between groups. Significant differences in kinematics were found between national and provincial athletes. At the moment of the left knee's minimum flexion (T2), in the first serve, national athletes had a smaller shoulder-hip vertical plane angle (-18.281 ± 6.142° vs. -25.631 ± 3.497°; p = 0.047) and a larger hip vertical plane rotation angle (-9.378 ± 4.263° vs. -0.470 ± 4.724°; p = 0.047). In the second serve, national athletes had a smaller hip horizontal plane rotation angle (-1.720 ± 4.683° vs. 24.146 ± 24.014°; p = 0.047) but a larger hip vertical plane rotation angle (-11.553 ± 1.949° vs. -0.422 ± 4.958°; p = 0.009). At the moment of impact (T4), in the second serve, national athletes' batting position (0.296 ± 0.088 m vs. 0.446 ± 0.094 m; p = 0.047) was further back. Additionally, in the second serve, national athletes consistently had their body center of gravity further back at T2 (-0.106 ± 0.052 m vs. -0.018 ± 0.048 m; p = 0.028), T3 (0.002 ± 0.038 m vs. 0.132 ± 0.039 m; p = 0.009), and T4 (0.073 ± 0.050 m vs. 0.217 ± 0.034 m; p = 0.009). The results of this study indicated several significant kinematic differences between national and provincial athletes, these variations were noted in the shoulder, hip, and body center of gravity. In summary, for the overall first and second serves, it is recommended that national athletes increase the horizontal plane angle of the shoulders and hips at T2, whereas provincial athletes decrease the horizontal plane angle of the shoulder-hip. In addition, provincial athletes need to increase the vertical plane angle of the hip joint, so that the top of the hip can be increased more, and provincial athletes need to be careful not to have the center of gravity too far in front of the body at T2, T3, and T4, so that it can hit the ball at a higher position to increase the swing speed.

Promotion of nerve regeneration and motor function recovery in SCI rats using LOCAS-iPSCs-NSCs

BackgroundSpinal cord injury (SCI) is a severe traumatic spinal condition with a poor prognosis. In this study, a scaffold called linearly ordered collagen aggregates (LOCAS) was created and loaded with induced pluripotent stem cells (iPSCs)-derived neural stem cells (NSCs) from human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) to treat SCI in a rat model.MethodsThe rats underwent a complete transection SCI resulting in a 3-mm break at either the T9 or T10 level of the spinal cord.ResultsScanning electron microscope analysis revealed a uniform pore structure on the coronal plane of the scaffold. The LOCAS had a porosity of 88.52% and a water absorption of 1161.67%. Its compressive modulus and stress were measured at 4.1 MPa and 205 kPa, respectively, with a degradation time of 10 weeks. After 12 weeks, rats in the LOCAS-iPSCs-NSCs group exhibited significantly higher BBB scores (8.6) compared to the LOCAS-iPSCs-NSCs group (5.6) and the Model group (4.2). The CatWalk analysis showed improved motion trajectory, regularity index (RI), and swing speed in the LOCAS-iPSCs-NSCs group compared to the other groups. Motor evoked potentials latency was lower and amplitude was higher in the LOCAS-iPSCs-NSCs group, indicating better neural function recovery. Histological analysis demonstrated enhanced neuronal differentiation of NSCs and nerve fiber regeneration promoted by LOCAS-iPSCs-NSCs, leading to improved motor function recovery in rats. The LOCAS scaffold facilitated ordered neurofilament extension and guided nerve regeneration.ConclusionsThe combination of LOCAS and iPSCs-NSCs demonstrated a positive therapeutic impact on motor function recovery and tissue repair in rats with SCI. This development offers a more resilient bionic microenvironment and presents novel possibilities for clinical SCI repair.

Gait analysis in the early stage of Parkinson's disease with a machine learning approach.

Gait disorder is a prominent motor symptom in Parkinson's disease (PD), objective and quantitative assessment of gait is essential for diagnosing and treating PD, particularly in its early stage. This study utilized a non-contact gait assessment system to investigate gait characteristics between individuals with PD and healthy controls, with a focus on early-stage PD. Additionally, we trained two machine learning models to differentiate early-stage PD patients from controls and to predict MDS-UPDRS III score. Early-stage PD patients demonstrated reduced stride length, decreased gait speed, slower stride and swing speeds, extended turning time, and reduced cadence compared to controls. Our model, after an integrated analysis of gait parameters, accurately identified early-stage PD patients. Moreover, the model indicated that gait parameters could predict the MDS-UPDRS III score using a machine learning regression approach. The non-contact gait assessment system facilitates the objective and quantitative evaluation of gait disorder in PD patients, effectively distinguishing those in the early stage from healthy individuals. The system holds significant potential for the early detection of PD. It also harnesses gait parameters for a reasoned prediction of the MDS-UPDRS III score, thereby quantifying disease severity. Overall, gait assessment is a valuable method for the early identification and ongoing monitoring of PD.

Isotonic Exercises Associated With Swing Speed And Exit Velocity In Baseball Players

Isotonic Exercises Associated With Swing Speed And Exit Velocity In Baseball Players

Development of an IoT-enabled smart baby cradle for enhanced infant monitoring and parental control

raditional infant monitoring systems are evolving into intelligent solutions, offering real-time notifications and automation to cater to the demands of multitasking parents. However, most IoT solutions in parental care focus solely on monitoring, lacking automatic smartphone control. In response to this gap, we developed an IoT-based system for automatic cradle monitoring. This system not only enables smartphone-based monitoring but also allows parents to control the cradle's swing speed and receive notifications through a mobile application. Our solution integrates PIR and sound sensors, an ESP8266 microcontroller, and a Wi-Fi module to create a robust monitoring system that tracks a baby's movements and sounds, sending instant notifications to the smartphone. The user can activate the system and adjust the cradle's motion using a slider based on sensor data. This IoT-enabled smart baby cradle enhances convenience and reduces parental stress, ensuring infant well-being and safety. A survey conducted among Universiti Teknologi MARA instructors revealed that 70% preferred automatic swing cradles over traditional ones, and 80% expressed the need for IoT integration in infant cradles, highlighting the growing demand for such advanced solutions.

Quantifying and analysing the angular momentum in volleyball jump serve during the aerial phase: relationship to arm swing speed.

In volleyball, the jump serve is a crucial and commonly used serving technique. Nonetheless, the angular momentum developed during the jump serve remains unexplored. The objectives of the current study were to determine the angular momentum manifesting during the airborne phase of the jump serve and to analyse the correlations between the angular momentum variables and arm swing speed. Three-dimensional coordinate data were obtained during the jump serves of 17 professional male volleyball players. Correlation and linear regression analyses were used to identify the angular momentum variables linked to the arm swing speed at ball impact (BI). The arm swing speed at BI exhibited significant correlations with the peak angular momentum of the attack arm (r = 0.551, p = 0.024), non-attack arm (r = 0.608, p = 0.011), non-attack leg (r = -0.516, p = 0.034), forearm (r = 0.527, p = 0.032), and hand (r = 0.824, p < 0.001). A stepwise regression model (R2 = 0.35, p = 0.043) predicted arm swing speed based on the peak angular momentum of the non-attack leg, forearm, and hand. The study results suggest that during the arm-acceleration phase, (1) increasing angular momentum with the non-attack leg helps maintain aerial body balance, thereby enhancing arm swing execution, and (2) controlling the magnitude and timing of the force exerted by the elbow and wrist is crucial for effectively transmitting angular momentum, contributing to an increase in arm swing speed.

The effect of baseball bat properties and participant ability on youth hit ball speed

The following describes the results of a batting cage study involving youth batters hitting with three types of baseball bats in two weight classes. Participants were allowed to select a bat length from within each type and weight according to their preference. The bats were then swung in random order. Reflective markers were placed on the bats and balls, allowing infrared cameras to track their motion from which speed was obtained. Given the differing ability of the participants, the study outcomes were normalized to the swing speed of each batter. Bat performance was quantified from the bat-ball coefficient of restitution. Laboratory measures of bat performance were shown to strongly correspond with the peak batting cage results. The ball exit speed of hollow bats exceeded that of traditional solid wood bats by as much as 5%. The ball exit speed was also found to be affected more by players’ ability than the bat type. Batter swing speed correlated strongly with bat inertia and was relatively insensitive to the bat-ball impact location, showing that participant effort was not biased by impact quality. Batter swing speed tended to depend more strongly on bat inertia than has been found in adult studies, which may be due to the smaller size of youth participants.

Kinematic characteristics analysis of highly difficult movements "324C+1D" of the first level Wushu athletes

Background "324C+1D” movements are key techniques and winning factors in Wushu competitions. It is necessary for scientific training to analyze the kinematic characteristics of “324C+1D” by using the method of sports biomechanics. Methods In this study, 3D high-speed camera and 3D motion analysis software were used to study “324C+1D” completed by three Chinese wushu first-level athletes, and the kinematic characteristics of this movement were obtained. Results The run-up speed of completing the “324C+1D” is not high; The lift Angle of the center of gravity is close to 90°. The vertical height of the center of gravity is significantly higher than the vertical height of the center of gravity when landing, and the vertical moving distance of the center of gravity in the lifting stage is significantly less than the vertical moving distance of the center of gravity in the descending stage. The vertical height of the center of gravity at departure is significantly higher than that at landing. Conclusions In the take-off stage, increase the twisting Angle of shoulders and hips, speed up the swing arm speed and squat speed of the center of gravity in the vertical direction, and shorten the take-off time. Increase the vertical speed of the center of gravity before the patting foot and the vertical moving distance between the center of gravity lifting stage and the descending stage, extend the air time, accelerate the swing speed of the right leg, move the foot patting time forward to the rapid rising stage of the center of gravity lifting, accelerate the rotational angular speed of the shoulder shaft in the air stage and improve the strength of the leg, which is conducive to the athletes to complete the movement.

The Effect of Functional Training Programs to Improve Distance Hitting for Baseball Players in University

Background and Aim: In the field of baseball, the attacking ability of baseball players is mainly reflected in their hitting techniques, including hitting distance and swinging speed. At present, the level of domestic university baseball teams is still very low. From the data of hitting percentage, long hit percentage, and home run, it can be seen that the main problem is reflected in the insufficient ability to hit from a long distance. Therefore, it is difficult to have more multiple and home runs in the game, resulting in the team being unable to score. These shortcomings will hurt the overall athletic ability of the team. This study aims to address this issue by focusing on developing and implementing training programs specifically designed for the effect of functional training programs to improve distance hitting for baseball, to significantly improve the long-range hitting ability and swing speed of baseball players. Materials and Methods: This study is an experimental study. The research subjects are 20 baseball majors (18-22 years old) from Guangzhou Sports College in Guangdong Province, including 6 professional baseball coaches, 1 baseball instructor from a professional sports college, and 3 professors in the field of sports training, totaling 10 experts. This study used focus groups to develop and improve training plans through expert interviews and experimental analysis, with an IOC value of 0.914. This study mainly used analysis of variance to analyze the results before, 4 weeks after testing, and after testing. Result: After specialized functional training, the use of the T-seat hitting distance test and swing speed test effectively improved the long-distance hitting ability and swing speed of baseball players, and improved their long-distance hitting ability and swing speed, which helped to improve their athletic level and achieve better game results. Conclusion: After 8 weeks of baseball versatility training, 20 martial arts athletes underwent further tests on their long-range hitting ability and swing speed. This study analyzed the differences and their effects on long-range hitting ability and swing speed before and after training. The comparison before and after training fully proves that functional training in baseball can effectively improve the long-range hitting ability and swing speed of baseball players.

Digital Gait Outcomes for Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS): Discriminative, Convergent, and Ecological Validity in a Multicenter Study (PROSPAX).

With treatment trials on the horizon, this study aimed to identify candidate digital-motor gait outcomes for autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), capturable by wearable sensors with multicenter validity, and ideally also ecological validity during free walking outside laboratory settings. Cross-sectional multicenter study (four centers), with gait assessments in 36 subjects (18 ARSACS patients; 18 controls) using three body-worn sensors (Opal, APDM) in laboratory settings and free walking in public spaces. Sensor gait measures were analyzed for discriminative validity from controls, and for convergent (ie, clinical and patient relevance) validity by correlations with SPRSmobility (primary outcome) and Scale for the Assessment and Rating of Ataxia (SARA), Spastic Paraplegia Rating Scale (SPRS), and activities of daily living subscore of the Friedreich Ataxia Rating Scale (FARS-ADL) (exploratory outcomes). Of 30 hypothesis-based digital gait measures, 14 measures discriminated ARSACS patients from controls with large effect sizes (|Cliff's δ| > 0.8) in laboratory settings, with strongest discrimination by measures of spatiotemporal variability Lateral Step Deviation (δ = 0.98), SPcmp (δ = 0.94), and Swing CV (δ = 0.93). Large correlations with the SPRSmobility were observed for Swing CV (Spearman's ρ = 0.84), Speed (ρ = -0.63), and Harmonic Ratio V (ρ = -0.62). During supervised free walking in a public space, 11/30 gait measures discriminated ARSACS from controls with large effect sizes. Large correlations with SPRSmobility were here observed for Swing CV (ρ = 0.78) and Speed (ρ = -0.69), without reductions in effect sizes compared with laboratory settings. We identified a promising set of digital-motor candidate gait outcomes for ARSACS, applicable in multicenter settings, correlating with patient-relevant health aspects, and with high validity also outside laboratory settings, thus simulating real-life walking with higher ecological validity. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Non-motor symptoms associated with progressive loss of dopaminergic neurons in a mouse model of Parkinson's disease.

Parkinson's disease (PD) is characterized by three main motor symptoms: bradykinesia, rigidity and tremor. PD is also associated with diverse non-motor symptoms that may develop in parallel or precede motor dysfunctions, ranging from autonomic system dysfunctions and impaired sensory perception to cognitive deficits and depression. Here, we examine the role of the progressive loss of dopaminergic transmission in behaviors related to the non-motor symptoms of PD in a mouse model of the disease (the TIF-IADATCreERT2 strain). We found that in the period from 5 to 12 weeks after the induction of a gradual loss of dopaminergic neurons, mild motor symptoms became detectable, including changes in the distance between paws while standing as well as the swing speed and step sequence. Male mutant mice showed no apparent changes in olfactory acuity, no anhedonia-like behaviors, and normal learning in an instrumental task; however, a pronounced increase in the number of operant responses performed was noted. Similarly, female mice with progressive dopaminergic neuron degeneration showed normal learning in the probabilistic reversal learning task and no loss of sweet-taste preference, but again, a robustly higher number of choices were performed in the task. In both males and females, the higher number of instrumental responses did not affect the accuracy or the fraction of rewarded responses. Taken together, these data reveal discrete, dopamine-dependent non-motor symptoms that emerge in the early stages of dopaminergic neuron degeneration.

Design of Badminton Technical Movement Recognition System Based on Improved Agnes Algorithm

The Badminton Technical Movement Recognition System is a technology-driven solution aimed at identifying and analyzing various technical movements performed by badminton players during gameplay. Leveraging advanced sensors, motion tracking devices, and machine learning algorithms, this system captures and interprets data related to player movements, racket swings, footwork, and other key actions on the court. By analyzing this data in real-time or post-match, coaches, players, and analysts can gain valuable insights into performance, technique, and areas for improvement. The system's ability to recognize and quantify specific movements allows for detailed performance assessment, personalized training programs, and strategic game planning. The Badminton Technical Movement Recognition System serves as a powerful tool for enhancing player development and optimizing performance in the sport of badminton. The paper presents a comprehensive study on the application of the Multi-Modal AGNES algorithm across diverse domains, encompassing movement pattern estimation, modal feature extraction, coordinate estimation, and badminton feature estimation. Through rigorous experimentation and analysis, the algorithm's efficacy in accurately identifying movement patterns, robustly extracting features from varied datasets, precisely localizing objects in three-dimensional space, and proficiently estimating badminton-specific metrics has been demonstrated. Through rigorous experimentation and analysis, the algorithm's efficacy in accurately identifying movement patterns, robustly extracting features from varied datasets, precisely localizing objects in three-dimensional space, and proficiently estimating badminton-specific metrics has been demonstrated. For instance, the algorithm achieved an average accuracy of 90% in classifying movement patterns in a dataset of 1000 observations. Additionally, it accurately estimated modal features such as swing speed, racket angle, and shuttlecock speed with a mean error rate of less than 5%.

Effect of electroacupuncture on brain-gut oxidative stress in Parkinson's disease mice.

To observe the effect of electroacupuncture (EA) on behavior, oxidative stress factors in colon and substantia nigra of Parkinson's disease (PD) mice, so as to explore the mechanism of EA in treating PD. C57BL/6 mice were randomly divided into blank, model and EA groups, with 12 mice in each group. The PD mouse model was established by continuous gavage of rotenone for 4 weeks. Mice in the EA group received EA (2 Hz/15 Hz) at "Baihui" (GV20), "Quchi" (LI11) and "Zusanli" (ST36) for 20 min, 5 days a week for 2 weeks. After intervention, gait analysis was used to evaluate the motor ability and motor coordination. Ink propulsion rate was used to evaluate the intestinal transport function. The level of reactive oxygen species (ROS) in the colon was detected by flow cytometry. The contents of total protein (TP), malondialdehyde (MDA) and activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) in colon and substantia nigra were detected by ELISA. The expression of nuclear factor E2-related factor 2 (Nrf2) in substantia nigra was detected by immunofluorescence staining. Compared with the blank group, the average speed, step rate, normal step ratio, distance between the front and hind feet, stride length, swing speed and maximum intensity of the maximum contact area of mice in the model group were decreased (P<0.000 1, P<0.01, P<0.001), the maximum change rate of gait was increased (P<0.001) in the model group. The intestinal propulsion rate, the activities of GSH-Px and SOD in the colon and substantia nigra, and the positive expression of Nrf2 in substantia nigra were decreased (P<0.000 1, P<0.01, P<0.05), while the fluorescence intensity of ROS in the colon, the contents of MDA in colon and substantia nigra were increased (P<0.01). Compared with the model group, the average speed, step rate, normal step ratio, distance between the front and hind feet, stride length, swing speed, and maximum intensity of the maximum contact area of the mice in the EA group were increased (P<0.01, P<0.05, P<0.001, P<0.000 1), the maximum change rate of gait was decreased (P<0.01). The intestinal propulsion rate, the activities of GSH-Px and SOD in the colon and substantia nigra, the positive expression of Nrf2 in substantia nigra were increased (P<0.001, P<0.05, P<0.000 1), while the ROS fluorescence intensity in the colon, the MDA contents in the colon and substantia nigra were decreased (P<0.01). EA can improve the movement disorder, gait disorder and intestinal motor function of PD mice, and protect dopaminergic neurons from damage, which may be related to its effect in antagonistic brain-gut oxidative stress.

Research on the "shape-performance-control" integrated digital twin system for boom-type roadheaders

The boom-type roadheader plays a crucial role in coal mining. However, conducting the real-time monitoring of the mechanical performance and comprehensive adaptive cutting in the dynamic cutting process are challenging. To address these issues, a digital twin system that integrates the elements of “shape, performance, and control” for roadheaders is presented in this paper. The system comprises three components: physical space, service space, and twin space. The service space forms the core of the entire system. Within this space, twin models and control models are created using numerical simulation, artificial intelligence and multi-source data fusion technology. These models serve the purpose of predicting the roadheader’s mechanical performance and controlling the swing speed of the cutting arm. The physical space is built using technologies such as robot kinematics, electrical systems, hydraulic transmission, and other relevant techniques. This approach facilitates the transmission of multi-sensor data to twin models. The control model then manages the roadheader’s function based on the output signals from the control model. The twin space is constructed utilizing physical rendering engines, databases, and 3D modelling tools. This space visualizes and stores the movement, performance, and control parameters of the roadheader. The results demonstrate that the average absolute error between the measured data from the test’s three position strain gauges and the predicted data from the twin system is 10.38 MPa. Furthermore, the twin system achieves an average update interval of 0.34 s, allowing real-time stress monitoring of the structural components of the roadheader and preventing damage caused by overload. The proposed control model enables adaptive adjustment of the swing speed of the cutting arm in approximately 0.3 s. This improvement significantly enhances the adaptive cutting capabilities of roadheaders when dealing with complex coal and rock formations.

Improvement in Microstructure and Properties of 304 Steel Wire Arc Additive Manufacturing by the Micro-Control Deposition Trajectory.

In this study, the GMAW welding torch was controlled by a stepping motor to achieve a periodic swing. By controlling the swing speed, a micro-variable deposition path was obtained, which was called the micro-control deposition trajectory. The influence of the micro-control deposition trajectory on the arc characteristics, microstructure, and mechanical properties of 304 steel wire arc additive manufacturing was studied. The results showed that the micro-control deposition process was affected by the swing arc and the deposition trajectory and that the arc force was dispersed over the whole deposition layer, which effectively reduced the welding heat input. However, the arc centrifugal force increased with the increase in the swing speed, which easily caused instability of the arc and large spatter. Compared with common thin-walled deposition, the deposition width of micro-control thin-walled deposition components was increased. In addition, the swinging arc had a certain stirring effect on the molten pool, which was conducive to the escape of the molten pool gas and refinement of the microstructure. Below, the interface of the deposition layer, the microstructure of the common thin-walled deposition components, and the micro-control thin-walled deposition components were composed of lathy ferrite and austenite. Compared with the common deposition, when the swing speed increased to 800 °/s, the microstructure consisted of vermicular ferrite and austenite. The tensile strength and elongation of the micro-control thin-walled deposition components are higher than those of the common thin-walled deposition components. The tensile fracture mechanism of the common thin-walled deposition components and the micro-control thin-walled deposition components was the ductile fracture mechanism.

The relationship among swing speed and strength and asymmetry of lower limbs of college baseball hitters

&lt;p&gt;目的：本研究旨在檢視大專棒球打者之大腿中部等長拉力測驗 (isometric mid-thighpull test, IMTP ) 的肌力表現以及其雙側差異與揮棒速度的關聯。方法：大學棒球野手20 名，進行 IMTP 與揮棒速度測驗後，依照其絕對力量對稱指數值分為低 (LSI)、中 (MSI)、高 (HSI) 力量對稱組，比較三組在揮棒速度與力量表現的差別，以及分析全體及分組在變項之間的關係。結果：全體參與者的力量峰值與揮棒速度有顯著的關係 (p &lt; .05)。各組間在揮棒速度、力量的峰值和發力率皆無顯著的差異。HIS 的力量表現與球速有正相關，而 LSI 則相反。各組的發力率、力量峰值間有不同的正向關聯：HIS 的力量峰值與 250 毫秒的發力率有關，MSI 的各分段的發力率幾乎都有所關聯，LSI 的 150 毫秒發力率與力量峰值有顯著的關係。結論：下肢等長拉力的峰值越大，揮棒速度越快。不同程度的力量不對稱性，會有不同的力量發展型態以及與揮棒速度的關係。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;Purpose: The presented study aimed to examine the relationship between isometric mid-thigh-pull test (IMTP) and swing speed in college baseball hitters. Methods: Twenty college fielders participated and implemented the tests of IMTP and swing speed. They then were divided into low (LSI), medium (MSI), and high (HSI) force symmetry groups according to their absolute force symmetry index values. The differences in swing speed and IMTP performances were compared between three groups, and the patterns of relationship in variables for overall and groups were analyzed. Results: There was a significant relationship between peak force and swing speed (p &lt; .05). No significant difference was found between groups in swing speed and IMTP performances. HSI and LSI have different relationships between force and ball speed in which the HSI has positive relationship while reverse for LSI. The relation between force development rate and peak force value were varied in groups in which the HSI had related peak force value and force development rate of 250ms, the MSI had relations in most force development rates, and the LSI had significant relation between force development rate of 150ms and peak force value. Conclusion: The greater the peak isometric midthigh pull force of the lower body, the faster the swing. Different degrees of force asymmetry will have different force development patterns and relationships with swing speed.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Effects of α1-antitrypsin on motor function in mice with immature brain white matter injury

To investigate the effects of α1-antitrypsin (AAT) on motor function in adult mice with immature brain white matter injury. Five-day-old C57BL/6J mice were randomly assigned to the sham surgery group (n=27), hypoxia-ischemia (HI) + saline group (n=27), and HI+AAT group (n=27). The HI white matter injury mouse model was established using HI methods. The HI+AAT group received intraperitoneal injections of AAT (50 mg/kg) 24 hours before HI, immediately after HI, and 72 hours after HI; the HI+saline group received intraperitoneal injections of the same volume of saline at the corresponding time points. Brain T2-weighted magnetic resonance imaging scans were performed at 7 and 55 days after modeling. At 2 months of age, adult mice were evaluated for static, dynamic, and coordination parameters using the Catwalk gait analysis system. Compared to the sham surgery group, mice with HI injury showed high signal intensity on brain T2-weighted magnetic resonance imaging at 7 days after modeling, indicating significant white matter injury. The white matter injury persisted at 55 days after modeling. In comparison to the sham surgery group, the HI+saline group exhibited decreased paw print area, maximum contact area, average pressure, maximum pressure, paw print width, average velocity, body velocity, stride length, swing speed, percentage of gait pattern AA, and percentage of inter-limb coordination (left hind paw → left front paw) (P<0.05). The HI+saline group showed increased inter-paw distance, percentage of gait pattern AB, and percentage of phase lag (left front paw → left hind paw) compared to the sham surgery group (P<0.05). In comparison to the HI+saline group, the HI+AAT group showed increased average velocity, body velocity, stride length, and swing speed (right front paw) (P<0.05). The mice with immature brain white matter injury may exhibit significant motor dysfunction in adulthood, while the use of AAT can improve some aspects of their motor function.

Gait Analysis of Hemiparetic Adult Patients with a Quadripod Cane and a Rolling Cane.

Stroke consequences include hemiparesis and difficulty walking. Several types of canes exist to overcome these alterations, but little data compares the quadripod cane and the rolling cane in hemiparetic patients. The objective of this work is twofold: to determine whether the gait speed-the most often used parameter to assess gait performance-depends on the type of cane, and to establish which spatiotemporal parameters have the most influence. Thirty-four hemiparetic patients performed 10 m walking tests at comfortable and fast speed conditions, using both canes on two different days. To objectively analyze their gait patterns, we used a tri-axial Inertial Measurement Units (IMU)-based system to record the walking signals from which we extracted the gait spatiotemporal parameters. We particularly examined the speed, stride length, and durations of stance, swing, and double support phases. The results showed that hemiparetic patients walked faster with the rolling cane during both speed conditions. These speed increases could be explained by the decrease in the stance phase duration of the affected leg, the decrease in the double support duration, and the increase in cadence. Our findings suggest that the rolling cane allows safe and faster walking.

Effect of nerve growth factor on elderly degenerative knee osteoarthritis pain

To explore effect of nerve growth factor (NGF) antibody on knee osteoarthritis (KOA) pain model was evaluated by in vitro model. Thirty male SPF rats aged 28-week-old were divided into blank group (10 rats with anesthesia only). The other 20 rats were with monoiodoacetate (MIA) on the right knee joint to establish pain model of OA, and were randomly divided into control group (injected intraperitoneal injection of normal saline) and treatment group (injected anti-NGF) intraperitoneal after successful modeling, and 10 rats in each group. All rats were received retrograde injection of fluorogold (FG) into the right knee joint. Gait was assessed using catwalk gait analysis system before treatment, 1 and 2 weeks after treatment. Three weeks after treatment, right dorsal root ganglia (DRG) were excised on L4-L6 level, immunostained for calcitonin gene-related peptide (CGRP), and the number of DRGS was counted. In terms of gait analysis using cat track system, duty cycle, swing speed and print area ratio in control and treatment group were significantly reduced compared with blank group (P<0.05). Compared with control group, duty cycle and swing speed of treatment group were significantly improved (P<0.05), and there was no significant difference in print area ratio between treatment group and blank group (P>0.05). The number of FG-labeled DRG neurons in control group was significantly higher than that in treatment group and blank group (P<0.05). The expression of CGRP in control group was up-regulated, and differences were statistically significant compared with treatment group (P<0.05). Intraperitoneal injection of anti-NGF antibody inhibited gait injury and upregulation of CGRP in DRG neurons. The results suggest that anti-nerve growth factor therapy may be of value in treating knee pain. NGF may be an important target for the treatment of knee OA pain.