ECSS Paris 2023: CP-BM07
INTRODUCTION: This study aimed to analyze the activation of four upper body muscles during the execution of a forehand smash in table tennis employing two different racket coverings: inverted and short-pimpled. METHODS: A cohort of twelve female table tennis players at the university level, aged 21.19 ± 2.35 years, with dimensions of 162.9 ± 6.8 cm in height and 66.8 ± 6.1 kg in weight, each possessing a minimum of 3 years of competitive table tennis experience, was recruited. Participants were assessed for physical fitness and recent competitive participation before inclusion. Electromyographical recordings were conducted on four selected upper body muscles: Trapezius (TPZS), Tricep Brachii (TRCP), Biceps Brachii (BB), and Anterior Deltoid (AD). Root Mean Square (RMS), a crucial EMG signal parameter indicative of maximum muscle activation, was calculated for each muscle during play with both racket coverings. The paired t-test was utilized to compare electromyographical signal differences between racket coverings. Descriptive statistics, including mean and standard deviation, were employed. Significance was established at p < 0.05. RESULTS: Findings revealed no significant differences in muscle activation levels between racket coverings. Nonetheless, BB and TPZS exhibited higher RMS values with the Inverted covering, whereas TRCP and AD displayed higher RMS values with the short-pip covering. CONCLUSION: The forehand smash, a top offensive stroke in table tennis, presents challenges in precision control, particularly when targeting specific areas. Some previous research has explained the greater spin generation associated with inverted rubber compared to pimpled rubber.
Read CV Radhika MishraECSS Paris 2023: CP-BM07
INTRODUCTION: Badminton is a popular racket sport and requires players to hit slow and fast shots to take advantage in rallies. One of the most important shots in badminton is the drive shot. To use the drive shot effectively, players must adjust the velocity of hitting the shuttlecock. Identifying the shuttlecock velocity adjustment strategy in backhand drive would provide coaches with knowledge to assist them in providing appropriate instruction, but no research has been examined from this perspective. Therefore, this study aimed to identify differences between skilled and unskilled players with regard to strategies for controlling shuttlecock velocity on the backhand drive. METHODS: Ten male college badminton players (Age: 19.4 ± 1.0 year, height: 173.3 ± 4.5 cm, Weight: 64.2 ± 3.8 kg, Experience: 10.5 ± 1.4 year) and ten adult men with no experience in badminton (Age: 21.5 ± 0.6 year, height: 173.5 ± 5.0 cm, Weight: 64.5 ± 9.7 kg) are volunteered for this study. Participants performed backhand drives in the sitting position. Participants were instructed to control the shuttlecock velocity with effort (from 60% to 100%). Upper limb movement and shuttlecock trajectory were recorded with a motion capture system (Mac3D, Motion Analysis Co., USA). Shuttlecock velocity and upper limb joint (elbow extension, forearm supination, and wrist flexion) angular velocity were calculated for each effort level. Data were compared within each proficiency level using repeated measures of one-way analysis of variance (ANOVA) with effort level as a factor; when appropriate multiple comparison tests using Holms method were performed for items. The significance level was set at p < 0.05. RESULTS: In skilled participants, shuttle velocity was significantly higher at the higher effort levels across all effort levels (p < 0.05) except between the 70%-80% (p = 0.060) and 80%-90% (p = 0.060) effort levels. Maximum angular velocity in the elbow and wrist were significantly higher depending on effort levels (p < 0.05). In contrast, shuttle velocity in unskilled participants was significantly higher at the higher effort levels across all effort levels (p < 0.05) except between 60%-70% (p = 0.742), 70%-80% (p = 0.058), and 60%-80% (p = 0.233). The forearm and wrist maximum angular velocity increased depending on shuttle velocity in unskilled participants (p < 0.05). CONCLUSION: Skilled participants adjusted the shuttlecock velocity appropriately by adjusting the angular velocity of the elbow and wrist joints. Unskilled participants attempted to adjust the shuttlecock velocity appropriately by adjusting the angular velocity of the forearm and wrist joints. However, the unskilled could not properly control the joint angular velocity at low effort levels. As a result, the unskilled could not also control the shuttlecock velocity. In conclusion, it was found that skilled participants and unskilled participants swung with different shuttlecock velocity adjustment strategies.
Read CV Mikiya ShimizuECSS Paris 2023: CP-BM07
INTRODUCTION: Smashing is pivotal in badminton, and to boost performance, players or coaches may tweak the weight or balance of the racket. Badminton racket specifications, particularly variations in weight, significantly influence athletes performance and technique. Rackets are typically categorized as neutral balance, head-heavy, or head-light, depending on the balance point. Pros often customize rackets by adding lead weights to adjust weight and balance, thereby enhancing swing weight, and ultimately, improving performance in terms of speed and accuracy. In a prior study, Hsieh et al. (2004) explored how different racket weights affect limb movement speed during smash execution. They found heavier rackets (100g) had notably faster speeds than lighter ones (85g) (p < .05). However, the impact of different weight distributions on smash performance remains unclear. Furthermore, the study did not specify if participants were singles or doubles players, hampering tailored recommendations for doubles players using varied racket specifications. Hence, this study aims to examine how using rackets with different weights affects smash technique in badminton doubles players, focusing on shuttlecock speed, accuracy, and upper limb and trunk kinematic parameters. METHODS: Nine elite badminton players participated in the research. Motion analysis was conducted using an 11-camera infrared system with a sampling frequency of 400Hz to capture standing smash techniques. One-Way Analysis of Variance (ANOVA) was employed to compare sports performance and kinematic parameters among doubles players when utilizing different rackets. Descriptive statistics are presented as mean ± standard deviation, with a significance level set at p < .05. RESULTS: Regarding athletic performance, doubles players utilizing Racket 1 demonstrated a significant advantage over those using Racket 3. In terms of linear kinematics, the study findings reveal that during the swinging process, the linear acceleration peak of the racket center in doubles players is significantly higher when using Rackets 1 and 2 compared to Racket 3. CONCLUSION: Doubles players using Racket 1 showed significant performance advantages over Racket 3 users. They employ tactics with more flat drives and swift smashes, indicating a higher hitting frequency. Their ability to execute rapid movements within a fast-paced rhythm may make them less responsive to increased racket weight during smashing. Notably, racket speed is significantly affected only by a 10g increase in racket head weight, with no impact on accuracy. Doubles players using Rackets 1 and 2 have notably higher linear acceleration peaks compared to Racket 3, suggesting a link between acceleration pattern and racket propulsion technique. A lighter racket, especially concerning racket center linear acceleration, may facilitate swift adaptation to the fast-paced game environment. Doubles players are better suited to rackets with a lower swing weight (101.8 kg - cm²).
Read CV HONGPENG YUECSS Paris 2023: CP-BM07