Kong, Pui Wah

This study aimed to quantify the break shot characteristics and identify their significance in predicting the game outcomes in 9-ball tournaments. The break shots of 275 frames (241 men’s, 34 women’s) of professional tournaments were analyzed from two aspects: (1) cue ball position, represented by the distance between the cue ball and the table center, and (2) ball distribution, indicated by the standard deviation of Voronoi cell areas determined from all remaining balls on the table. Spearman correlation and binary logistic regression were utilized to identify associations and to predict the frame outcomes, respectively. Results showed that the more balls falling into the pockets during the break, the more clustered the remaining balls (rs = 0.232, p < 0.001). The closer the cue ball ending toward the table center, the more balls potted in the visit immediately after the break (rs = −0.144, p = 0.027). Neither cue ball position nor ball distribution could predict table clearance or winning of a frame. In conclusion, pocketing more balls during the break is associated with more clustered balls remaining on the table. Parking the cue ball near the table center after the break can facilitate potting more balls immediately after.

Firefighters often experience low back pain (LBP), but their back muscle characteristics are not well studied. This study aimed to 1) compare the biomechanical characteristics of back muscles and self-reported back disabilities in frontline firefighters with and without LBP history, and 2) examine the relationships between back disability and biomechanical measurements. We recruited 42 male firefighters and assessed their perceived pain and disabilities, maximum isometric back extension strength, passive stiffness, and fatigability of the longissimus. 54.8% of the participants experienced LBP within the past year. Those indicating higher pain intensity also had greater disability as indicated by the Oswestry Disability Index. There were no significant differences in strength, stiffness or fatigability of the back muscles between firefighters with and without LBP history. Multiple linear regression analysis revealed no significant relationship between the back disability and any biomechanical or demographic measures, likely due to the high functional abilities of the participants.

The purpose of this study was to examine the effects of low-Dye tape on comfort and ground reaction forces (GRF) in flat-footed female runners. A randomized cross-over study was conducted on 15 flat-footed female recreational runners. Participants ran at three speeds (9, 10, 11 km/h) under two conditions: low-Dye and sham taping. Comfort level was assessed using a 150-mm visual analog scale. GRF data were collected using an instrumented treadmill. Stance time, peak forces, and loading rates were extracted. Low-Dye taping showed a lower comfort level (low-Dye, 63.8 (24.3) mm, sham 122.0 (16.0) mm, mean difference [95% confident intervals], -58.2 [68.2, 48.2] mm, p < 0.001). For all biomechanical variables, there was no interaction (taping condition a speed) effect or difference between taping conditions. As running speed increased, there was a decrease in stance time (p < 0.001) and increase in loading rate (p = 0.009), impact peak (p = 0.004), active peak (p < .001), breaking peak (p < 0.001), propulsive peak (p < 0.001), medial peak (p < 0.001), and lateral peak (p < 0.001). Compared with sham taping, application of low-Dye taping was less comfortable but did not alter running ground reaction forces among flat-footed female runners.

Heightened stress during air pistol competitions may impair shooters’ abilities to maintain gun stability, resulting in inferior performance. This study aimed to compare the pre-trigger muscle activation levels of upper muscles in 10-m air pistol shooters between training and simulated competition conditions. Seven sub-elite shooters from the Singapore National Youth Air Pistol Team shot 30 shots in a training versus simulated competition condition in randomised orders on separate days. Muscle activation for the forearm and shoulder muscles, namely extensor carpi radialis, flexor carpi ulnaris, anterior deltoid, and posterior deltoid, were recorded using electromyography (EMG). Shooting performance was evaluated by total shot scores. Stress level was monitored via heart rate and the Mental Readiness Form-3. No statistically significant differences were found in EMG, performance, or stress-related variables between conditions, although moderate-to-large effect sizes were observed in some muscle activation and self-reported stress indicators. Analysis of individual performances using smallest worthwhile change showed that two participants improved under the simulated competition condition, while two declined, and three remained unaffected. In conclusion, sub-elite youth air pistol shooters were able to exhibit good neuromuscular control under high anxiety situations and thus their performance was largely unaffected.

This study examined the influence of basketball shoe midsole inserts with different forefoot and rearfoot rebound properties on biomechanical loading and subjective perception during a side-cutting maneuver. Eleven male basketball players executed side cutting in four shoe conditions mechanically characterized for their rearfoot/forefoot rebound: compliant/compliant, springy/springy, compliant/springy, and springy/compliant. Lower extremity kinetics and kinematics (normalized to body mass), as well as subjective perception, were measured. During the weight-acceptance phase, there were no differences between shoes in all biomechanical variables, except a slightly greater ankle range of motion (1.2° greater than the other three shoes) in the frontal plane for shoe compliant/springy. During the push-off phase, shoe springy/springy led to a greater ankle plantarflexion moment (1.21 Nm/kg greater than the other three shoes, p < 0.001) and knee internal rotation moment (0.09 Nm/kg greater than the other three shoes, p = 0.012), while shoe compliant/springy resulted in a greater ankle range of motion in the frontal plane (1.4° greater than the other three shoes, p < 0.001). Perception data showed no statistically significant difference among any shoes. In conclusion, springy inserts of basketball shoe midsoles induced a biomechanical loading effect. Perception of players being unaffected indicates the importance of biomechanical evaluation to examine the effects of the given shoe modifications during side cutting.

This study aimed to examine the influence of court surface on foot loading when executing typical basketball tasks. Thirteen male basketball players performed three basketball-related tasks: Layup, jump shot, and maximal effort sprint on wooden and asphalt courts. In-shoe plantar loading was recorded during the basketball movements and peak force (normalised to body weight) was extracted from eight-foot regions. Perceptions of discomfort at the ankle, knee, and back were surveyed using a 10-cm visual analogue scale. Landing from a layup on the wooden court resulted in elevated peak forces at the hallux (p = 0.022) and lesser toes (p = 0.007) compared with asphalt court. During the sprint acceleration step, higher peak forces were observed at the hallux (p = 0.048) and medial forefoot (p =0.010) on wooden court. No difference between court surfaces was found for perception ratings at the ankle, knee, or back. These results suggested that players can experience greater impact forces at the toes and medial forefoot when performing basketball tasks on the more compliant wooden court than asphalt courts.

Previous studies generally selected one foot to classify participants into groups with different foot types and then analyzed the running or walking biomechanics for one limb. Such approach may have neglected the possible differences in foot morphology and gait between two limbs. This study aimed to compare the foot morphological characteristics and running kinematics of the lower extremities between the left and right limbs among a group of healthy, asymptomatic runners. Forty-four participants [20 females, 24 males; age 25.1 (6.5) years old; height 167.2 (7.0) cm; body mass 62.8 (8.1) kg] were recruited. Foot morphological characteristics were measured for both feet, and bilateral running kinematics were analyzed with 2D video analysis. No significant between-limb differences were found in the foot dimensions, hallux valgus (bunion) angle, or navicular drop (all p > 0.05). On the other hand, several kinematic variables were significantly different between the left and right limbs during running, including the peak foot eversion (p = 0.014), peak knee flexion (p = 0.002), and peak hip adduction (p < 0.001). The results indicate that runners with similar morphological characteristics between the left and right feet can display between-limb gait asymmetry during running. Researchers and practitioners should be aware of the potential between-limb asymmetry in running kinematics and foot morphology. Future studies should avoid arbitrarily analyzing one limb to represent a runner’s gait or foot morphology.

Background This study aimed to develop new test protocols for evaluating 9-ball expertise levels in cue sports players. Methods Thirty-one male 9-ball players at different playing levels were recruited (recreational group, n = 8; university team, n = 15; national team, n = 8). A 15-ball test was administered to indicate overall performance by counting the number of balls potted. Five skill tests (power control, cue alignment, angle, back spin, and top spin) were conducted to evaluate specific techniques by calculating error distances from pre-set targets using 2D video analysis. Results Intra-class correlation analyses revealed excellent intra-rater and inter-rater reliability in four out of five skill tests (ICC > 0.95). Significant between-group differences were found in 15-ball test performance (p <  0.001) and absolute error distances in the angle (p <  0.001), back spin (p = 0.006), and top spin tests (p = 0.045), with the recreational group performing worst while the national team performing best. Greater inter-trial variability was observed in recreational players than the more skilled players (p <  0.005). Conclusions In conclusion, the 9-ball test protocols were reliable and could successfully discriminate between different playing levels. Coaches and researchers may employ these protocols to identify errors, monitor training, and rank players.

Patellofemoral pain (PFP) is a common injury in runners, especially females, but it is unclear if the kinematic risk factors between the sexes are the same. This study aimed to identify the kinematics of healthy and injured recreational runners with PFP in both sexes. High-speed videos of treadmill running gait in 56 subjects (14 in each injured and non-injured male and female group) were analysed using the Kinovea software. Three kinematic variables associated with PFP were extracted at midstance: knee midstance position, knee flexion angle, and hip adduction angle. Compared with healthy controls, injured females ran with knees more medially positioned (Left p = 0.008, Right p < 0.001), while injured males ran with less knee flexion (Left p = 0.006, Right p = 0.007). These findings suggest that kinematic risk factors associated with PFP are sex-specific.

Snooker can be an attractive life-long physical activity, given its popularity across all age groups in Asia and Europe. However, scientific research on the cueing movement is limited. This case study presented the biomechanical profiles of the cueing movement in an elite male snooker player (age 37 years old, height 173 cm, body mass 70 kg). Kinematics of the upper limb and cue stick, were examined in five selected snooker tasks (warm-up, stun, top spin, back spin, and stop shots) using the Vicon motion capture system. Ground reaction forces and centre of pressure characteristics were recorded using two Kistler force platforms. Results showed that the cueing movement was contributed primarily by elbow flexion/extension and much less wrist flexion/extension. The high degree of cue stick position overlap between the practice swing and final stroke indicated high level of cueing precision. Weight transfer between feet revealed a slight lean towards the left foot throughout the final stroke, confirming that the elite player was able to maintain high stance stability when executing the cueing movement. Results presented in the present study can serve as a reference for practitioners and scientists to detect error, enhance training, and improve performance in snooker. For practical applications, snooker players are advised to stabilise their shoulder during the cueing movement and deliver the cue stick primarily via elbow movements.