Impact of specialized fatigue and backhand smash on the ankle biomechanics of female badminton players.

During fatigued conditions, badminton players may experience adverse effects on their ankle joints during smash landings. In addition, the risk of ankle injury may vary with different landing strategies. This study aimed to investigate the influence of sport-specific fatigue factors and two backhand smash actions on ankle biomechanical indices. Thirteen female badminton players (age: 21.2 ± 1.9 years; height: 167.1 ± 4.1 cm; weight: 57.3 ± 5.1 kg; BMI: 20.54 ± 1.57 kg/m2) participated in this study. An 8-camera Vicon motion capture system and three Kistler force platforms were used to collect kinematic and kinetic data before and after fatigue for backhand rear-court jump smash (BRJS) and backhand lateral jump smash (BLJS). A 2 × 2 repeated measures analysis of variance was employed to analyze the effects of these smash landing actions and fatigue factors on ankle biomechanical parameters. Fatigue significantly affected the ankle-joint plantarflexion and inversion angles at the initial contact (IC) phase (p < 0.05), with both angles increasing substantially post-fatigue. From a kinetic perspective, fatigue considerably influenced the peak plantarflexion and peak inversion moments at the ankle joint, which resulted in a decrease the former and an increase in the latter after fatigue. The two smash landing actions demonstrated different landing strategies, and significant main effects were observed on the ankle plantarflexion angle, inversion angle, peak dorsiflexion/plantarflexion moment, peak inversion/eversion moment, and peak internal rotation moment (p < 0.05). The BLJS landing had a much greater landing inversion angle, peak inversion moment, and peak internal rotation moment compared with BRJS landing. The interaction effects of fatigue and smash actions significantly affected the muscle force of the peroneus longus (PL), with a more pronounced decrease in the force of the PL muscle post-fatigue in the BLJS action(post-hoc < 0.05). This study demonstrated that fatigue and smash actions, specifically BRJS and BLJS, significantly affect ankle biomechanical parameters. After fatigue, both actions showed a notable increase in IC plantarflexion and inversion angles and peak inversion moments, which may elevate the risk of lateral ankle sprains. Compared with BRJS, BLJS poses a higher risk of lateral ankle sprains after fatigue.

Integrated Rehabilitation Approach Utilizing Swiss Ball Training, Mulligan Taping, and Mobilization With Movement for Simultaneous Management of Sacroiliac Joint Dysfunction and Lateral Ankle Sprain in a Badminton Athlete: A Case Study.

This case report details an integrated rehabilitation plan implemented for a professional badminton player who presented with issues of sacroiliac joint (SIJ) dysfunction and a lateral ankle sprain. The integrated approach aimed to address both musculoskeletal issues, considering their potential reciprocal influences on biomechanics and functional performance. The athlete underwent a thorough initial assessment, including clinical examination, imaging, and biomechanical analysis. Treatment began with targeted interventions for acute ankle sprain management, such as rest, ice, compression, and elevation (RICE) followed by progressive exercises to restore ankle stability and range of motion (ROM). Concurrently, a specialized program was devised to address the underlying sacroiliac joint dysfunction through manual therapy, therapeutic exercises, and core stabilization routines. Throughout the rehabilitation process, the focus remained on integrated exercises that targeted both the ankle and sacroiliac joint, promoting optimal neuromuscular coordination and joint function specific to badminton demands. Regular reassessments guided the progression of interventions, ensuring a personalized and athlete-centric approach. The positive outcome highlights the importance of a holistic rehabilitation strategy in managing complex musculoskeletal conditions in athletes, facilitating efficient recovery, and reducing the risk of recurrence. This case report highlights the effectiveness of an integrated approach in enhancing performance and preventing reinjury in badminton athletes facing multifaceted musculoskeletal challenges.

Return to badminton play following an ACL injury is common, but only a few return to previous performance.

PURPOSE: To report how many badminton players return to badminton after an anterior cruciate ligament (ACL) injury and to which level. METHODS: Patients in Denmark from 2000 to 2018, registered in the Danish National Patient Register with a diagnosis of ACL rupture and badminton as a primary sport were asked about a return to sport (RTS) and return to performance (RTP) after ACL injury. RTP was defined as the return to full participation in the same sport, same level and same preinjury performance. To investigate the likelihood of RTS and return to preinjury level, a binominal logistic regression was used. RESULTS: Badminton was the primary sport for 900 participants. Only 435 players were injured during badminton, and 626 participants intended to RTP. RTS was achieved by 396 (63%) and 117 (19%) returned to the same performance as their preinjury level. However, 273 (44%) returned to full participation at the same level as the preinjury level but did not perform as well. Males had a significantly higher RTS than females, and RTP was also higher among males [221 (68%) vs. 175 (58%), odds ratio, OR: 1.67, p = 0.003 and 74 (23%) vs. 43 (14%), OR: 1.58, p = 0.05]. CONCLUSION: Return to badminton was achieved by 396 (63%), but only 117 (19%) returned to the same performance as their preinjury level after ACL injury. Females are less successful in RTS and RTP. Future research on improving RTS and the RTP rates in badminton, in general, and specifically for females is needed. LEVEL OF EVIDENCE: Level II.

Fatigue Affects Body Acceleration During Vertical Jumping and Agility Tasks in Elite Young Badminton Players.

BACKGROUND: Badminton is a sport demanding both high aerobic and anaerobic fitness levels, and fatigue can significantly impact game performance. However, relevant studies are limited, and none have employed a wearable inertial measurement unit (IMU) to investigate the effects of fatigue on athletic performance in the field. HYPOTHESIS: Overall performance and body acceleration in both time and frequency domains during the fundamental badminton skills of vertical jumping and changes of direction will be affected by fatigue. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 38 young badminton players competing at the Division I level participated. Body accelerations while performing vertical jump and agility-T tests before and immediately after undergoing a fatigue protocol were measured by an IMU, positioned at the L4 to L5 level. RESULTS: Jumping height decreased significantly by 4 cm (P < 0.01) after fatigue with greater downward acceleration (1.03 m/s2, P < 0.05) during the squatting subphase. Finishing time increased significantly by 50 ms only during the 10-m side-shuffling of the agility-T test (P = 0.02) after fatigue with greater peak and mean accelerations (3.83 m/s2, P = 0.04; 0.43 m/s2, P < 0.01), and higher median and mean frequency (0.38 Hz, P = 0.04, 0.11 Hz, P = 0.01). CONCLUSION: This study using a wearable IMU demonstrates the effects of fatigue on body acceleration in badminton players. The frequency-domain analysis further indicated that fatigue might lead to loss of voluntary control of active muscles and increased impacts on the passive elastic elements. CLINICAL RELEVANCE: The findings imply that fatigue can lead to diminished athletic performance and highlight the potential for an increased risk of sports injuries. Consequently, maintaining precision in monitoring fatigue is crucial for elite young badminton players.

Quantifying Hitting Load in Racket Sports: A Scoping Review of Key Technologies.

PURPOSE: This scoping review aims to identify the primary racket and arm-mounted technologies based on inertial measurement units that enable the quantification of hitting load in racket sports. METHODS: A comprehensive search of several databases (PubMed, SPORTDiscus, Web of Science, and IEEE Xplore) and Google search engines was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) extension for scoping reviews guidelines. Included records primarily focused on monitoring hitting load in racket sports using commercialized racket or arm-mounted inertial sensors through noncompetitive and competitive racket-sports players. RESULTS: A total of 484 records were identified, and 19 finally met the inclusion criteria. The largest number of systems found were compatible with tennis (n = 11), followed by badminton (n = 4), table tennis (n = 2), padel (n = 1), and squash (n = 1). Four sensor locations were identified: grip-attached (n = 8), grip-embedded (n = 6), wrist (n = 3), and dampener sensors (n = 2). Among the tennis sensors, only 4 out of the 11 (36.4%) demonstrated excellent reliability (>.85) in monitoring the number of shots hit either during analytic drills or during simulated matches. None of the other racket-sports sensors have undergone successful, reliable validation for hitting-volume quantification. CONCLUSIONS: Despite recent advancements in this field, the quantification of hitting volume in racket sports remains a challenge, with only a limited number of tennis devices demonstrating reliable results. Thus, further progress in technology and research is essential to develop comprehensive solutions that adequately address these specific requirements.

Effects of plyometric training on skill-related physical fitness in badminton players: A systematic review and meta-analysis.

Skill-related physical fitness significantly correlates with sports performance. Plyometric training (PT) is an effective method for improving physical fitness in athletes. However, its impact on skill-related physical fitness in badminton players remains uncertain. Therefore, this systematic review and meta-analysis aimed to evaluate the effectiveness of PT on skill-related physical fitness in badminton players. Five electronic databases (Web of Science, PubMed, SCOPUS, MEDLINE, and SPORTSDiscus) were searched until February 2024. A PICOS approach was used to identify inclusion criteria, (1) healthy badminton players, (2) a PT program, (3) an active control group, (4) a measure of skill-related physical fitness before and after PT, and (5) randomized controlled studies. The PEDro scale was used to assess the methodological quality of PT studies, while the level of evidence certainty was determined through the GRADE framework. The calculation of effect sizes (ESs) was based on mean values and standard deviations, and heterogeneity was measured with the I2 statistic. The extended Egger's test was employed to check for publication bias. Eleven studies comprising 445 badminton players were eligible for inclusion. The analysis revealed significant small-to-moderate effects of PT on power (ES = 0.60, p < 0.001), agility (ES = 0.96, p < 0.001), speed (ES = 0.63, p = 0.001), and balance (ES = 0.89; p = 0.013). However, no significant effect was observed for reaction time (ES = 0.56; p = 0.189). The certainty of evidence for outcomes was graded as either low or very low. In conclusion, our findings demonstrate that PT improved power, agility, speed, and balance, but not reaction time in badminton players. However, the small number of studies and the very low to low certainty evidence mean that these results need to be interpreted with caution.

Influence of Torsional Stiffness in Badminton Footwear on Lower Limb Biomechanics.

Torsional stiffness of athletic footwear plays a crucial role in preventing injury and improving sports performance. Yet, there is a lack of research focused on the biomechanical effect of torsional stiffness in badminton shoes. This study aimed to comprehensively investigate the influence of three different levels of torsional stiffness in badminton shoes on biomechanical characteristics, sports performance, and injury risk in badminton players. Fifteen male players, aged 22.8 ± 1.96 years, participated in the study, performing badminton-specific tasks, including forehand clear stroke [left foot (FCL) and right foot (FCR)], 45-degree sidestep cutting (45C), and consecutive vertical jumps (CVJ). The tasks were conducted wearing badminton shoes of torsional stiffness measured with Shore D hardness 50, 60, and 70 (referred to as 50D, 60D, and 70D, respectively). The primary biomechanical parameters included ankle, knee, and MTP joint kinematics, ankle and knee joint moments, peak ground reaction forces, joint range of motion (ROM), and stance time. A one-way repeated measures ANOVA was employed for normally distributed data and Friedman tests for non-normally distributed data. The 70D shoe exhibited the highest ankle dorsiflexion and lowest ankle inversion peak angles during 45C task. The 60D shoe showed significantly lower knee abduction angle and coronal motions compared to the 50D and 70D shoes. Increased torsional stiffness reduced stance time in the FCR task. No significant differences were observed in anterior-posterior and medial-lateral ground reaction forces (GRF). However, the 70D shoe demonstrated higher vertical GRF than the 50D shoe while performing the FCR task, particularly during 70% - 75% of stance. Findings from this study revealed the significant role of torsional stiffness in reducing injury risk and optimizing performance during badminton tasks, indicating that shoes with an intermediate level of stiffness (60D) could provide a beneficial balance between flexibility and stability. These findings may provide practical references in guiding future badminton shoe research and development. Further research is necessary to explore the long-term effects of altering stiffness, considering factors such as athletic levels and foot morphology, to understand of the influence of torsional stiffness on motion biomechanics and injury prevalence in badminton-specific tasks.

Does dynamic balance affect cube mental rotation task in badminton vs. volleyball female players?

BACKGROUND: Changing from a static to a dynamic balance condition could affect the performance of a cognitive task such as mental rotation. Thus, the main goal of this study is to investigate aspects of visual-spatial cognition between two non-contact sports (i.e., badminton and volleyball) in different upright conditions (i.e., standing position, frontal balance, and sagittal balance). METHODS: Thirty-five volunteer female sports and physical education students, fourteen specialists in badminton and twenty-one specialists in volleyball agreed to participate in this study. Each of the assessments was a 3D cube mental rotation task with and/or without balance exercises (i.e., frontal and/or sagittal balance) on a wobble board. Five stimuli were used in the mental rotation task (i.e., 45°, 135°, 180°, 225° and 315° for objected-based cube condition with egocentric transformation) which included pairs of standard and comparison images. RESULTS: The findings indicate that there was a notable decrease (p < 0.001; d = 1.745) in response time in both dynamic balance conditions (i.e., frontal and sagittal balance) compared to standing position condition. In addition, results revealed significant interaction between balance conditions (i.e., frontal and/or sagittal balance) and groups (i.e., badminton and volleyball) in the response time at 225° angle and in the error percentage. CONCLUSIONS: In sum, dynamic balance is also an activity that involves mental manipulation of objects in 3D space, which can enhance badminton and volleyball female players' ability to rotate 3D cube stimuli.

An empirical study of indoor air quality in badminton stadiums in hot summer and cold winter regions of China during spring and fall seasons.

The indoor air quality has a direct impact on human health. In order to obtain the current status of indoor air quality in typical sports buildings in hot summer and cold winter climate zones in China, indoor badminton courts in 10 cities in Hubei Province in this climate zone were selected as research objects for field testing of indoor environmental parameters in spring and autumn, and predict air quality parameters for non-testing times. All the tested stadiums are naturally ventilated in non-event conditions, and the average daily indoor CO2 concentration was 526.78 ppm in spring and 527.63 ppm in autumn, and the average daily PM2.5 concentration was 0.035 mg/m3 in spring and 0.024 mg/m3 in autumn, all of which met the requirements of GB/T 18883-2022, the average concentration of CO2 ≤ 1000 ppm and PM2.5 ≤ 0.05 mg/m3. The indoor CO2 concentration and PM2.5 concentration of the tested badminton halls under natural ventilation gradually increased with the accumulation of exercise time, making the indoor air quality of the badminton halls decrease, which would negatively affect the health of the people exercising in this environment.

Optimizing Agility and Athletic Proficiency in Badminton Athletes Through Plyometric Training: A Review.

This review study investigates the advantages of plyometric training in badminton, concentrating on the effects on agility, power, speed, and overall athletic performance. It looks at the research on plyometric training in badminton, including training methods, performance effects, and potential injury prevention. The study underlines the value of plyometric training in enhancing agility, letting athletes move swiftly around the court, and producing the explosive force needed for quick and accurate strokes. It also looks at how plyometric training affects jumping ability and explosiveness, with a concentration on vertical jumps and hard smashes. In addition, the research explores the function of plyometrics in injury prevention in the physically demanding sport of badminton. Plyometric training has emerged as a key component in lowering injury risk and extending player life by strengthening muscles and connective tissues and boosting stability. The review study objectively reviews the existing corpus of research to provide a full picture, considering prior studies' strengths and limitations. It gives coaches, athletes, and trainers concrete ideas for incorporating plyometric activity into their badminton training routines. The study gives readers actionable recommendations for improving agility and athletic performance in badminton athletes by tailoring plyometric exercises to the unique demands of the sport and addressing safety concerns. In a sport where margins of victory are frequently razor-thin, embracing the possibilities of plyometric training can provide a competitive edge, ultimately improving the performance and success of badminton competitors.

A Systematic Review on the Effectiveness of Eyewear in Reducing the Incidence and Severity of Eye Injuries in Racket Sports.

PURPOSE: To assess what eyewear (if any) reduces eye injury incidence and severity in squash, racketball, tennis and badminton. DESIGN: Systematic review following the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' (PRISMA) and the 'implementing Prisma in Exercise, Rehabilitation, Sport medicine and SporTs science' (PERSiST) guidelines. METHODS: PubMed, SportDiscus and Web of Science were searched on 22nd February 2023. All study types except reviews were eligible. Studies had to report the type of eyewear worn (if any) with a form of eye injury incidence and severity. RESULTS: 364 papers were initially retrieved and after the screening process 29 remained. A subgroup analysis was carried out on studies that had a sample size of five or above, were not only looking at a particular type of eye injury and that had sufficient data to allow the percentage of eye injuries that occurred when no eyewear was worn to be calculated. From this analysis, the median percentage of eye injuries that occurred when no eyewear was worn was found to be 93%. Some of these injuries were serious and required complex treatment. Prescription lenses, contact lenses and industrial eyewear made some injuries more severe. In squash and racketball, lensless eye guards were ineffective as the ball could deform on impact, still making contact with the eye. Only eyewear compliant with updated ASTM (or similar) standards was associated with no eye injuries and so provided adequate protection in all four sports. CONCLUSIONS: Although this systematic review only summarizes evidence on injuries requiring hospital treatment, it is recommended that national governing bodies and key decision makers within squash, racketball, tennis and badminton examine the evidence presented and consider extending existing rules or implementing new recommendations and policies on protective eyewear use to reduce eye injury incidence and severity in their sport.

A novel mathematical model of the badminton smash: simulation and modeling in biomechanics.

Applied physics and computer methods in biomechanics have been extensively used in sports science research, including performance and biomechanics analysis. The Brachistochrone problem, which expresses the curve that an object draws quickly under gravitational forces in a vertical position, is one of the most widely used studies in classical mechanics. A similar problem arises when a badminton player intends to hit a smash with the shortest shot time. This paper aims to determine the optimal stroke trajectory for a shuttlecock smash in the shortest time. We simulate the badminton smash movement using a computer program after analyzing the shuttlecock smash analytically and numerically for several conditions. The modeling results show that a cycloid trajectory allows badminton players to smash the shuttlecock in the shortest time. Based on the experimental findings of Tsai, Huang, and Jih's study and our models, the ratio of clear speed to smash speed is 0.75, which is still in the range of 0.71 to 0.76, and we find that a cycloid trajectory gives the shortest shuttlecock smash time. We concluded that the experimental data from this study's literature supported our model. The novelty of this study is that we found the first powerful model and simulation of conventional Brachistochrone in the case of a badminton smash of badminton players. For badminton coaches and players, this model formulation is intended as a reference for optimizing shuttlecock shots. Furthermore, another novelty of this research is that it may lead to software that can be used to analyze the muscle strength of badminton players based on their cycloid hand trajectory and shuttlecock speed.

Aplicação do programa shuttle time no ensino do badminton na escola: refletindo relações de gênero / Application of the shuttle time program in teaching badminton at school: reflecting gender relations / Aplicación del programa shuttle time en la enseñanza del bádminton en la escuela: reflejando las relaciones de género

O objetivo deste estudo é descrever sobre a questão de gênero nas aulas de badminton na Educação Física escolar. O estudo trata-se de um relato de experiência de abordagem qualitativa e de natureza descritiva. Participaram do estudo duas turmas de 7º anos de uma escola pública. Os instrumentos de coleta de dados foram dois questionários e observação participante. Construímos uma sequência didática, contendo dez aulas com momentos dialógicos e vivenciais. Os dados revelam que a questão de gênero foi refletida e compreendida pelos e pelas estudantes nas aulas de badminton. Consideramos que os objetivos propostos na sequência didática foram alcançados, tendo em vista que as relações de gênero foram potencializadas por meio das vivências e das reflexões.

The objective of this study is to describe the gender issue in badminton classes in school Physical Education. The study is an experience report with a qualitative approach and descriptive nature. Two 7th grade classes from a public school participated in the study. The data collection instruments were two questionnaires and participant observation. We built a didactic sequence, containing ten classes with dialogical and experiential moments. The data reveal that the gender issue was reflected and understood by students in badminton classes. We consider that the objectives proposed in the didactic sequence were achieved, considering that gender relations were enhanced through experiences and reflections.

El objetivo de este estudio es describir la problemática de género en las clases de bádminton en la Educación Física escolar. El estudio es un relato de experiencia con enfoque cualitativo y carácter descriptivo. En el estudio participaron dos clases de séptimo grado de una escuela pública. Los instrumentos de recolección de datos fueron dos cuestionarios y la observación participante. Construimos una secuencia didáctica que contiene diez clases con momentos dialógicos y vivenciales. Los datos revelan que la cuestión de género fue reflejada y comprendida por los estudiantes en las clases de bádminton. Consideramos que se lograron los objetivos propuestos en la secuencia didáctica, considerando que las relaciones de género se potenciaron a través de experiencias y reflexiones.

The Impact of Hemispheric Activity Priming on Choking Under Pressure in Badminton Tasks: A Study of Three Fundamental Skills.

Choking under pressure occurs when an individual experiences a decrease in performance despite their efforts to perform well. The self-focus approach suggests that pressure increases conscious attention on the performance process, disrupting the automatic or overlearned nature of execution. Hemispheric asymmetries in the brain and skilled performance indicate that left-hemispheric activity decreases, while right-hemispheric activity enhances. Previous studies have attempted to prevent choking by inhibiting the left hemisphere or enhancing the right hemisphere's activity. This study examined whether increased hemispheric activity priming can extenuate motor skill failure under pressure in badminton tasks. The study involved 32 right-handed college students who completed five conditions in pressure-free blocks versus choking under-pressure blocks with priming intervention. Results showed a significant improvement in motor learning from pre- to post-tests, but participants still choked under pressure during skill execution. Furthermore, the priming strategy (hand squeezing) did not alleviate the pressure to benefit performance. The study provides evidence of performance decrements under pressure conditions, and the priming strategy did not alleviate choking.

Self-Attention-Based Deep Convolution LSTM Framework for Sensor-Based Badminton Activity Recognition.

Sensor-based human activity recognition aims to classify human activities or behaviors according to the data from wearable or embedded sensors, leading to a new direction in the field of Artificial Intelligence. When the activities become high-level and sophisticated, such as in the multiple technical skills of playing badminton, it is usually a challenging task due to the difficulty of feature extraction from the sensor data. As a kind of end-to-end approach, deep neural networks have the capacity of automatic feature learning and extracting. However, most current studies on sensor-based badminton activity recognition adopt CNN-based architectures, which lack the ability of capturing temporal information and global signal comprehension. To overcome these shortcomings, we propose a deep learning framework which combines the convolutional layers, LSTM structure, and self-attention mechanism together. Specifically, this framework can automatically extract the local features of the sensor signals in time domain, take the LSTM structure for processing the badminton activity data, and focus attention on the information that is essential to the badminton activity recognition task. It is demonstrated by the experimental results on an actual badminton single sensor dataset that our proposed framework has obtained a badminton activity recognition (37 classes) accuracy of 97.83%, which outperforms the existing methods, and also has the advantages of lower training time and faster convergence.

Gender-Specific Patterns of Muscle Imbalance in Elite Badminton Players: A Comprehensive Exploration.

The high-intensity demands of overhead sports exert significant stress on the bilateral shoulder complex, triggering adaptive kinematics and a distinct strength imbalance between internal and external rotators. The imbalance being referred to in the given statement poses a potential risk for humeral head displacement and puts nearby tendons under tension, heightening the vulnerability to injury. This study aims to assess muscle imbalances in badminton athletes. The first hypothesis (H1) suggests that there are differences in internal and external shoulder rotation movements between dominant and non-dominant segments in badminton players. The second hypothesis (H2) proposes that there are variations in muscle imbalances based on gender among elite badminton players. The objectives are to analyze these differences and explore potential gender-related variations in muscle imbalances. The study seeks to contribute to the understanding of muscle imbalances in badminton athletes and potentially guide training and injury prevention strategies in the sport. Using a cutting-edge Hand-Held Dynamometer (HHD), a cohort of 30 elite badminton players underwent an assessment to uncover any bilateral shoulder rotation strength imbalances during a challenging five second isometric maximum contraction. The participants boasted an average age of 17.4 years and a mean playing experience of 7.23 years. The study revealed a notable difference in the ratio of external and internal strength between the dominant and non-dominant shoulders (p = 0.000). This discrepancy amounted to a striking 27.93% muscle imbalance in external rotation/internal rotation strength ratios, favoring the dominant shoulder. Moreover, gender-specific differences were detected, with male players exhibiting a 24.54% muscle imbalance in favor of the dominant shoulder, while female players showcased a more substantial 31.33% imbalance (p = 0.000). In light of these findings, it became evident that elite badminton players possess considerably stronger dominant shoulders compared with their non-dominant counterparts. Furthermore, the study revealed that male players experience less muscular imbalance than their female counterparts.

Dose-response effect of incremental lateral-wedge hardness on the lower limb Biomechanics during typical badminton footwork.

Badminton footwork has been characterised with jump-landing, cross step, side side and lunges, which requires movement agility to facilitate on-court performance. A novel badminton shoe design with systematic increase of lateral wedge hardness (Asker C value of 55, 60, 65, and 70) was developed and investigated in this study, aiming to analyse the dose-response effect of incremental wedge hardness on typical badminton footwork. Stance time and joint stiffness were employed to investigate the footwork performance, and the factorial Statistical non-Parametric Mapping and Principal Component Analysis (PCA) were used to quantify the biomechanical responses over the stance. As reported, shorter contact times (decreased by 8.9%-13.5%) and increased joint stiffness (in side step) of foot-ankle complex were found, suggesting improved footwork stability and agility from increased hardness. Time-varying differences were noted during the initial landing and driving-off phase of cross and side steps and drive-off returning of lunges, suggesting facilitated footwork performance. The reconstructed modes of variations from PCA further deciphered the biomechanical response to the wedge dosage, especially during drive-off, to understand the improved footwork agility and stability.

Comparison of mechanical energy transfer during right-forward lunge between female amateur and professional badminton players.

BACKGROUND: Regarding their skill levels, badminton players present different movement patterns during front and right lunging. The main objective of this study was to compare the mechanical energy transfers attributable to right-forward lunges between amateur and professional badminton players to study variations in mechanical efficiency at various skill levels. METHOD: In this cross-sectional study, twenty female badminton players were recruited (Professional group n = 10 and Amateur group n = 10). The kinematics and kinetics of the lower extremities were recorded while performing right-forward lunges using Vicon motion capture and Kistler force plates. Mechanical energy expenditures (MEE) were extracted in eccentric transfer, concentric transfer, and no-transfer phases for the hip, knee, and ankle joints. At each joint, mechanical energy compensations (MEC) were also determined. Independent samples t-tests were used to analyze data at a significance level of α = 0.05. RESULT: Regards to mechanical energy expenditures at the initial heel contact phase, the professional players demonstrated statistically significant more ankle no-transfer (p < 0.003), less knee concentric transfer (p < 0.026), more knee eccentric transfer (p < 0.001), and less hip no-transfer (p < 0.001). At the same time, the amateur athletes showed significantly more ankle eccentric transfer (p < 0.042) at maximal knee flexion angle time point. Analyzing mechanical energy compensation coefficients showed that the professional athletes had significantly less ankle concentric transfer (p < 0.001), more knee concentric transfer (p < 0.001), more knee eccentric transfer (p < 0.001), and more hip eccentric transfer (p < 0.001) at initial contact phase. While they found to have significantly more ankle eccentric transfer (p < 0.007), less knee concentric transfer (p < 0.001), less knee eccentric transfer (p < 0.001), more hip concentric transfer (p < 0.001), and more hip eccentric transfer (p < 0.001) at maximal knee flexion angle. CONCLUSION: it is shown that the mechanical energy efficiency of the right-forward lunge is skill-related. It seems that altered lunge landing biomechanics may increase the risk of ankle and knee injuries and muscular damages in amateur athletes. It is recommended for amateur players to follow a injury prevention training program that promotes proper lunging technique.

Training drills in high performance badminton-effects of interval duration on internal and external loads.

Purpose: The aim of the present study was to analyze the impact of interval duration on training loads and technical skill performance in high performance badminton drills. Methods: On three experimental days, 19 internationally ranked players (13 male: 22.7 ± 3.8 years, 180 ± 6 cm, 71.5 ± 6.1 kg; 6 females: 20.4 ± 2.5 years, 168 ± 4 cm, 59.8 ± 6.0 kg) completed one of three protocols (T10, T30, and T50) of a typical badminton specific drill, the so-called "Multifeeding" (the coach feeds shuttlecock without break in a random order) in a counterbalanced order. The protocols varied in interval duration (10, 30, and 50 s) but were matched for the rally-to-rest-ratio (1:1) and active playing time (600 s). Cardiorespiratory responses (portable spirometry, chest belt), energy metabolism (levels of blood lactate, La), rate of perceived exertion (RPE), player's kinematics (Local Positioning System), and technical skill performance (video analysis) were measured. Results: Average oxygen consumption (T10 45 ± 6; T30 46 ± 7; T50 44 ± 6 mL min-1·kg-1), Energy expenditure (886 ± 209; 919 ± 176; 870 ± 206 kcal h-1), heart rate (164 ± 13; 165 ± 11; 165 ± 10 bpm) and RPE (16 ± 2; 17 ± 2; 17 ± 2) did not differ between the protocols. Respiratory exchange ratio (RER) and La significantly increased depending on interval duration (RER: 0.90 ± 0.05; 0.93 ± 0.03; 0.96 ± 0.04 and La: 3.6 ± 2.0; 5.6 ± 3.0; 7.3 ± 2.3 mmol l-1). Stroke frequency (SF; 0.58 ± 0.05; 0.57 ± 0.05; 0.55 ± 0.06 strokes·s-1) was similar while distance covered, and average running velocity were significantly lower for T50 compared to T10 (76 ± 17; 70 ± 13; 65 ± 11 m min-1). Moreover, jump frequency in T30 was higher than in T10 (6.7 ± 3.1; 8.8 ± 3.8; 8.5 ± 4.2 jumps·min-1), whereas differences in internal and external loads were not associated with changes in stroke precision (errors: 16 ± 6; 19 ± 4; 18 ± 4%; accuracy: 22 ± 6; 24 ± 8; 23 ± 8%). Conclusion: Anaerobic metabolic stimulus increases while running distance and velocity decrease, in case of longer interval durations. Even though there was no impact on stroke precision, extending the intervals beyond 30 s might impair external training load and skill performance. Consequently, interval duration should be defined carefully depending on the training goals.

Experimental and Computer Simulation Studies on Badminton Racquet Strings.

This study investigates experimentally, numerically, and analytically the performance of different string materials (Kevlar, synthetic gut, natural gut, and polyester) on badminton racquets. Vibration and impact tests with a shuttlecock were performed using a racquet frame made of carbon graphite mixed with epoxy resin. Different string tensions were considered in the tests (20, 22, 24, 28, 30, and 34 lb), as well as different hitting locations on the racquet frame. The results show that, as the diameter of the strings increased, the elasticity of the string decreased from 0.529 to 0.447 for diameters ranging from 0.62 to 0.70 mm. Subsequently, a badminton racquet and shuttlecock were modeled using SolidWorks2018® software (version 26), and a maximum displacement was applied to the ball to simulate an impact on the string bed. The natural frequency, maximum deformation and maximum stress were calculated analytically, and a finite element analysis was also performed using ANSYS2022 R2® software (version 22.2). The analytical and numerical results from ANSYS® showed good agreement (within 5% accuracy). The results of the study show that the natural frequency of a racquet with Kevlar strings was significantly higher than that of racquets with synthetic gut, natural gut, or polyester string materials. Specifically, the natural frequency of a racquet made of carbon graphite and epoxy resin was 23.0%, 30.7%, and 36.2% higher than that of racquets with synthetic gut, natural gut, and polyester string material, respectively. On the basis of this finding, Kevlar was chosen as the preferred material for badminton racquets strings, and a parametric analysis was then conducted. The study showed that slightly lowering the tension of the off-centered strings had a minimal effect on the von Mises stress distribution of the ball and string bed. In addition to investigating string materials, this study also examined the effects of pull and diameter variations of racquet strings on vibrations during impact. This study contributes to the understanding of the role of racquet and strings in badminton, and it also provides new insights into the factors that can affect performance in the sport. By analyzing the performance of different string materials and examining the effects of pull and diameter variations of racquet strings, this study provides valuable information for players and manufacturers looking to optimize their equipment for maximum performance.