BACKGROUND: Previous investigations have shown a positive relationship between baseball pitching velocity and the kinetic chain involved in pitching motion. However, no study has examined the influence of finger characteristics on pitching velocity and rate of spin via a sensor-embedded baseball.
METHODS: Twenty-one pitchers volunteered and were recruited for this study. An experimental baseball embedded with a force sensor and an inertial measurement unit was designed for pitching performance measurement. Finger length and strength were measured as dependent variables. Spin rate and velocity were independent variables. Pearson product-moment correlations (r) and intraclass correlation coefficients (ICCs) determined the relationship between finger characteristics and pitching performance.
RESULTS: Finger length discrepancy, two-point pinch strength, index finger RFD (rate of force development), middle finger impulse, and force discrepancy had significant correlations with spin rate (r = 0.500~0.576, p ≤ 0.05). Finger length discrepancy, two-point pinch, three-point pinch strength, index and middle finger RFD, middle finger impulse, and force combination had significant correlations with fastball pitching velocity (r = 0.491~0.584, p ≤ 0.05).
CONCLUSIONS: Finger length discrepancy, finger pinch strength, and pitching finger force including maximal force and RFD may be factors that impact fastball spin rate and fastball pitching velocity.

Detecting the association between two variables is necessary and meaningful in the era of big data. There are many measures to detect the association between them, some detect linear association, e.g., simple and fast Pearson correlation coefficient, and others detect nonlinear association, e.g., computationally expensive and imprecise maximal information coefficient (MIC). In our study, we proposed a novel maximal association coefficient (MAC) based on the idea that any nonlinear association can be considered to be composed of some piecewise-linear ones, which detects linear or nonlinear association between two variables through Pearson coefficient. We conduct experiments on some simulation data, with the results show that the MAC has both generality and equitability. In addition, we also apply MAC method to two real datasets, the major-league baseball dataset from Baseball Prospectus and dataset of credit card clients\' default, to detect the association strength of pairs of variables in these two datasets respectively. The experimental results show that the MAC can be used to detect the association between two variables, and it is computationally inexpensive and precise than MIC, which may be potentially important for follow-up data analysis and the conclusion of data analysis in the future.

Previous research on fielding in cricket and baseball has focused on the technique and speed-accuracy trade-off of the throw in isolation from a typical sequence of fielding actions; approach, gather and throw. The present study aimed to determine whether a speed-accuracy trade-off existed in fielding and where within the above sequence the trade-off occurs. Participants, who were elite cricketers, were required to run to a stationary ball and throw to the centre of a target in order to run-out a virtual batter. High-speed video was used to record the time of approach, time in contact with, and time of flight of the ball. Two-way ANOVAs were used to determine differences in group (gender) and condition (instructions to prioritise speed or accuracy). A speed-accuracy trade-off was found, with both groups being quicker in the approach and spending less time in contact with the ball in the speed condition; however, the horizontal velocity of the throw remained the same in both conditions. It was proposed the drop in accuracy in the speed condition may be associated with less time spent aiming. It was found that instructions triggered a change in throwing technique for 31% of the participants, which requires further investigation.

The aims of the study were (1) to investigate glenohumeral internal rotation deficit (a difference in internal rotation of 15.6 degrees or more between dominant and nondominant shoulders) and its correlation with self-reported shoulder pain in table tennis players and (2) to find the optimal cutoff point for the difference in the internal rotation range of motion between dominant and nondominant shoulders of self-reported shoulder pain.
The internal rotation range of motion of both shoulders of 46 table tennis players was measured in the supine and side-lying positions, and the external rotation range of motion was measured in the supine position.
Significant differences existed in internal rotation range of motion between the two sides in the supine ( z = 6.53, P < 0.001) and side-lying positions ( z = 5.67, P < 0.001). Self-reported shoulder pain was associated with glenohumeral internal rotation deficit (odds ratio = 6.86, 95% confidence interval = 1.752-26.832, P = 0.006). The cutoff points for the difference in internal rotation range of motion between the sides of self-reported shoulder pain were 17.9 degrees in the supine position and 11.1 degrees in the side-lying position.
Table tennis players exhibited glenohumeral internal rotation deficit. There was a correlation between glenohumeral internal rotation deficit and self-reported shoulder pain in the past year; therefore, glenohumeral internal rotation deficit may be a risk factor for shoulder pain in table tennis players.

Baseball itself is a new sport. In the process of training, teachers often use traditional training methods, which leads to unsatisfactory training results. High-intensity intermittent and intensive interval training can better improve the efficiency of athletes\' oxidation and energy supply and ultimately play a positive role in improving athletes\' performance. This paper takes the influence of high-intensity and intensive interval training on the special endurance of baseball players as the research object. A series of functional training programs are developed through adaptive training, testing, coordination training, and recovery training. Through the use of experimental means to understand the influence of high-intensity interval training and intensive interval training on the physical fitness of baseball players, the paper is aimed at providing ways and means to improve the physical fitness level of baseball players in the future. Based on the experimental test data, functional training is different from traditional training methods to make up for the lack of training research. It is to improve the competitive ability of our baseball players and promote the development of our baseball. It plays an active role in improving the specific endurance, speed, and intermittent endurance of baseball players.

OBJECTIVE: To investigate the relationship between baseball bat-like gastric tubes for end-to-side oesophageal-gastric anastomosis and occurrence of anastomotic leakage after oesophagectomy for oesophageal cancer.
METHODS: From July 2019 to June 2021, 613 patients with bat-like or narrow gastric tubes for end-to-side oesophageal-gastric anastomosis in oesophagectomy were retrospectively enrolled, in which 120 patients had narrow gastric tubes and 493 had bat-like gastric tubes. Clinical data including baseline characteristics, in-hospital variables and follow-up outcomes were collected.
RESULTS: Higher occurrence of anastomotic leak was observed in the narrow group in the unmatched cohort (14.2%, 17/120 vs. 7.3%, 36/493; P = 0.016) or the matched cohort after Propensity Score Matching (PSM) analysis (14.2%, 17/120 vs. 7.5%, 27/360, P = 0.028) when compared to the bat-like group; Multivariable analysis for risk factors of postoperative anastomotic leak in the unmatched cohort showed that the use of bat-like gastric tube was an independent protective factor (OR: 0.502, 95% CI: 0.270-0.935, P = 0.030).
CONCLUSIONS: Bat-like gastric tube can be used for end-to-side oesophageal-gastric anastomosis in oesophagectomy. This technique by improving blood supply to the area distal to the anastomosis decreased the incidence of anastomotic leak.

Tai Chi softball was voted as one of the most popular health-promoting exercises and can also develop manipulative skill and hand-eye coordination. The purpose of this study was to explore changes in the physical fitness level and cardiovascular health-related factors after the 16-week Tai Chi softball (TCSB) training program among older females. One hundred healthy older females were assessed at the baseline before TCSB training, and then, they conducted intervention experiments. Through the 16-week TCSB intervention training, a control group and a physical exercise group showed significant differences. The physical exercise group significantly reduced body mass index, systolic blood pressure, and diastolic blood pressure from all the results studied. It also reduces total cholesterol, triglycerides, low-density lipoprotein cholesterol ( ∗ p < 0.05), and waist-to-hip ratio ( ∗∗ p < 0.01), whereas handgrip, sit and reach, single leg stance, vital capacity ( ∗ p < 0.05), and high-density lipoprotein cholesterol ( ∗∗ p < 0.01) were significantly increased. TCSB training may improve physical fitness ability and decrease the risk of cardiovascular disease among older females.

Bat-ball contacts are critical in the baseball hitting process. However, an effective training method for increasing the impact perception of a bat-ball contact is currently unavailable. Although not widely used, hitting a stationary weighted baseball can be an appropriate method for batters to simulate the perception of hitting a moving baseball. Therefore, swing velocity, wrist vibration, and forearm muscle activation for hitting stationary weighted, stationary regulation, and pitched baseballs were investigated in this study. Twelve position players hit a stationary weighted, stationary regulation, and pitched baseball at a speed of 70.28 ± 3.84 km/h in a random order. The swing velocity, wrist vibration, forearm muscle activation, and co-contraction ratio during hitting phases were analysed. The results indicated that the swing velocity during each specific phase demonstrated no significant differences between the different conditions. Hitting weighted and pitched baseballs caused higher wrist vibration, muscle activation, and co-contraction ratio during the contact phase than hitting regulation balls (p < 0.05). The conclusion was that hitting weighted baseballs could mimic the impact condition of hitting pitched baseballs without changing the pattern of swing velocity, which suggested that this method has potential as a hitting drill for improving hitting perception at bat-ball contact.

Purpose: Pitching machines are widely used for baseball batting practice. However, these machines cannot precisely simulate a live pitcher\'s pitching motion. To understand if a batter\'s movement strategy would be altered due to disparate visual information provided by a pitching machine as opposed to a live pitcher, the present study aimed to compare differences in baseball batting movement patterns under the two delivery conditions. Methods: To examine movement variations and different strategies of each high-level athlete rather than obtaining averaged group performance, single-subject analysis was adopted. Four professional baseball players were recruited to bat around 50 pitches under each delivery condition. Vertical ground reaction forces of the participants\' batting movements were recorded. Relative timings of key events and values of several kinetic parameters during batting were examined. Results: When batting against the pitching machine, batters initiated forward stepping earlier (relative to ball release), had smaller loading rate at landing the step, and altered the duration from forward bat swing to ball impact. These results might be attributed to lacking visual cues of a live pitcher\'s whole body kinematics prior to ball release. Without sufficient visual information, greater uncertainty and incomplete weight transfer affected the batter\'s decision making and movement execution. Conclusion: The batters in this study did adjust their movement strategy in batting against a pitching machine. With dissimilar batting movement patterns under the two delivery conditions, extensive reliance on training with pitching machines is not recommended.

The aim of this study was to determine whether weight training combined with high-protein intake enhances total and regional bone mineral density (BMD) in athletes.
BMD of 27 Division 1 collegiate baseball players 18 to 22 y of age (N = 13, 2 dropouts) received either 14% protein or isocaloric 44% protein supplements and were assessed by dual-energy x-ray absorptiometry before and after a 12-wk weight training program (challenging upper and lower body).
Baseline data showed unequivocally greater humerus BMD in the dominant arm than their contralateral non-dominant arm (∼20 %) among all baseball players. Humerus BMD of the non-dominant arm was enhanced by 2.7% after weight training for both low- and high-protein groups (main effect, P = 0.008), concurrent with an unexpected small decrease in total body BMD (main effect, P = 0.014). Humerus BMD of the dominant arm with greater baseline value than the non-dominant arm was not increased unless high protein was supplemented (+2.7 %; P < 0.05).
Bones with relatively higher BMD show blunt adaptation against training, which can be relieved by high-protein supplementation. Total BMD of athletes cannot be further elevated by weight training.