Assistive technology for Para-badminton athletes: the application of the matching person and technology theoretical model in occupational therapy

PURPOSE

The objective was to identify the AT demands of para-athletes in para-badminton and present the process of prescription, and follow-up of the AT devices. Also, to evaluate the expectations and the level of satisfaction with the service provided and the AT device.

MATERIALS AND METHODS

Case study with 3 professional para-badminton athletes, that had as baseline the Matching Person and Technology (MPT) model, the Para-athlete Questionnaire, the AT Device Predisposition Assessment (ATD PA-Br), the Quebec User Evaluation of Satisfaction with AT (B-QUEST) and an Observation Script. The data were analyzed using absolute frequency statistics, and the qualitative data were grouped according to the categories of the MPT model.

RESULTS

4 AT demands were identified: 1 insole, 1 wheelchair footrest adaptation, 1 armband, and 1 lower-limb strap, with prescription, and AT follow-up by the occupational therapist. The quantitative analysis showed a gain in athletes' satisfaction with the AT devices, and in the expectations achieved with the use of the device.

CONCLUSIONS

The role of the occupational therapist in parasports, based on a theoretical model, can contribute to the successful use of AT and therefore better performance of para-athletes. Studies with different populations are necessary to improve knowledge in the area.

Kinetic and kinematic determinants of shuttlecock speed in the forehand jump smash performed by elite male Malaysian badminton players

Badminton is the fastest racket sport in the world with smash speeds reaching over 111 m/s (400 kph). This study examined the forehand jump smash in badminton using synchronised force plates and full-body motion capture to quantify relationships to shuttlecock speed through correlations. Nineteen elite male Malaysian badminton players were recorded performing forehand jump smashes with the fastest, most accurate jump smash from each player analysed. The fastest smash by each participant was on average 97 m/s with a peak of 105 m/s. A correlational analysis revealed that a faster smash speed was characterised by a more internally rotated shoulder, a less elevated shoulder, and less extended elbow at contact. The positioning of the arm at contact appears to be critical in developing greater shuttlecock smash speeds. Vertical ground reaction force and rate of force development were not correlated with shuttlecock speed, and further investigation is required as to their importance for performance of the jump smash e.g., greater jump height and shuttle angle. It is recommended that players/coaches focus on not over-extending the elbow or excessively elevating the upper arm at contact when trying to maximise smash speed.

Headgear safety attitudes: a national survey of collegiate women's lacrosse stakeholders

Controversy exists among collegiate lacrosse about the use of headgear and whether its use will facilitate greater risk compensation by players and thus contribute to unsafe gameplay. We aimed to characterize the attitudes of headgear among women's collegiate lacrosse stakeholders. A total of 190 women's lacrosse stakeholders (players: n = 87; coaches: n = 71; officials: n = 32) participated in this study. Participants completed a survey surrounding attitudes of headgear in women's lacrosse. Descriptives, multiple regressions, and Kruskal-Wallis analyses compared attitudes surrounding headgear among stakeholder groups. Scales of Headgear Affects Play (β = -0.38, p < 0.001) and Sports Development and Safety Practices (β = 0.26, p < 0.05) significantly predicted endorsement on Headgear Safety Attitudes Scale. Among players, Aesthetics (β = 0.51, p < 0.001) and Intention to Wear Headgear (β = 0.31, p < 0.05) predicted endorsement on Headgear Safety Attitudes Scale. Stakeholders did not agree if headgear should be worn in women's lacrosse. Items related to sports development, safety and potential changes in gameplay predicted attitudes to headgear safety among all participants.

Better position for the wearable sensor to monitor badminton sport training loads

This study purposed to identify the better accelerometer location for monitoring badminton sports training load by investigating the correlation between internal (HR, training impulse [TRIMP]) training load and external (acceleration, player load [PL]) training loads measured from 5 different body locations. Twelve college-level badminton athletes wore a HR transmitter belt and five accelerometers fixed on both hands, legs, and lower back while performing continuous three-minute training of four badminton skills including backhand serve (BS), net shot (NS), footwork training (FT), and jump smash (JS). Results showed PL at the five locations were significantly related to TRIMP (r = 0.570-0.843, p < 0.05), in which PL at lower back has highest Pearson (r = 0.843) and partial (r = 0.366) correlated to TRIMP (p < 0.05). Base on the stepwise multiple regression, PL at lower back and racket hand explained 88% of the variance of TRIMP (R2 = 0.879). In conclusion, lower back is an idea location for accelerometer to monitor overall external training load in badminton if considering one accelerometer location, while combining PL at the lower back and racket hand can predict 88% of the variation of the internal training load.

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.

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.

Mechanical characterization of athletic helmet shells

Our purpose was to compare the mechanical properties of the protective outer shells of various athletic helmets in their final, fully manufactured form. Sections were taken from 3 different helmet shells (Bauer RE-AKT hockey helmet, Cascade R lacrosse helmet, and Riddell Speedflex football helmet) at 4 different locations (front, side, top, and rear) for a total of 12 test specimens. The 4 specimens from each helmet shell were potted together in epoxy resin moulds and mechanically polished. The hardness, elastic modulus and phase angle were measured using dynamic nanoindentation performed at 100 Hz with an oscillation amplitude of 1 nm (rms). Repeated ANOVA analysis was used to compare each of the dependent variables for each of the 3 helmets across the 4 different locations. The interaction between helmet type and location was significant for hardness (F6,63 = 2.84, P = 0.032, Pη2 = 0.21), elastic modulus (F6,63 = 6.412, P < 0.001, Pη2 = 0.38), and phase angle (F6,63 = 7.65, P < 0.001, Pη2 = 0.42). Polycarbonate has a higher ability to dissipate mechanical energy making it the recommended superior choice for helmet shells. In addition, the results lead us to speculate that manufacturing causes changes in the molecular weight or the distribution of fillers across locations for polyethylene but not for polycarbonate since mechanical properties are fairly uniform over the surface of football helmets, at least within a given helmet.

Effects of high-intensity interval training on strength, speed, and endurance performance among racket sports players: A systematic review

This study aims to present a critical review of the existing literature on the effects of High-Intensity Interval Training (HIIT) on strength, speed, and endurance performance among racket sports athletes. This study conducted a systematic literature review by PRISMA guidelines. Various well-known academic and scientific databases were used for research collection, including PubMed, EBSCOhost, Scopus, Web of Science, and Google Scholar. Out of 27 relevant studies, 10 were selected for inclusion in this systematic review, all meeting the required inclusion criteria. The quality of each study was assessed using the PEDro scale, with scores ranging from 3 to 5 for the selected studies. HIIT was found to improve racket players' VO2 max (maximum oxygen uptake), running and repetitive sprint performance, jumping performance, and hitting speed during play. Current findings indicate that HIIT can significantly benefit athletic performance. Long-term HIIT allows athletes to enhance their power while improving crucial variables related to both aerobic and anaerobic endurance. This anaerobic endurance and explosive power type is particularly vital for racket sports players. For example, athletes in table tennis and badminton must exert maximum effort during high-intensity middle and back-court play. Racket athletes also need to maintain a stable state while preserving ball speed and positioning, and must quickly recover to prepare for the next rally. This training mechanism can assist athletes in honing their skills and achieving more efficient hitting quality. Therefore, this paper recommends that racket sports athletes incorporate HIIT into their regular training routines. The suggested frequency is three times per week, with each training session lasting 30-40 minutes, and a total duration of six to eight weeks. Trial registration. Systematic Review Registration: [https://inplasy.com/], identififier[INPLASY20230080].

3D Knee and Hip Angle Estimation With Reduced Wearable IMUs via Transfer Learning During Yoga, Golf, Swimming, Badminton, and Dance

Wearable lower-limb joint angle estimation using a reduced inertial measurement unit (IMU) sensor set could enable quick, economical sports injury risk assessment and motion capture; however the vast majority of existing research requires a full IMU set attached to every related body segment and is implemented in only a single movement, typically walking. We thus implemented 3-dimensional knee and hip angle estimation with a reduced IMU sensor set during yoga, golf, swimming (simulated lower body swimming in a seated posture), badminton, and dance movements. Additionally, current deep-learning models undergo an accuracy drop when tested with new and unseen activities, which necessitates collecting large amounts of data for the new activity. However, collecting large datasets for every new activity is time-consuming and expensive. Thus, a transfer learning (TL) approach with long short-term memory neural networks was proposed to enhance the model's generalization ability towards new activities while minimizing the need for a large new-activity dataset. This approach could transfer the generic knowledge acquired from training the model in the source-activity domain to the target-activity domain. The maximum improvement in estimation accuracy (RMSE) achieved by TL is 23.6 degrees for knee flexion/extension and 22.2 degrees for hip flexion/extension compared to without TL. These results extend the application of motion capture with reduced sensor configurations to a broader range of activities relevant to injury prevention and sports training. Moreover, they enhance the capacity of data-driven models in scenarios where acquiring a substantial amount of training data is challenging.

Badminton as a dynamic system - A new method for analyzing badminton matches based on perturbations

This study presents a method for analysing badminton matches based on the concept of perturbations. We transfer this principle to a badminton rally and describe the decisive shot, which turns a balanced situation into an advantage for one team or one player. Our paper proposes an observational system, which models the decisive shots by using four consecutive actions: impulse (the perturbation), follow-up, survival, and convert. To test the objectivity of the operationalization, independent raters analysed six matches in the singles disciplines of the 2022 World Championships. To evaluate rater agreement, Jaccard coefficient and Cohen's kappa were used. Results show an agreement in identifying impulses of J(R1, R2) = .80, while the agreement in classifying the impulse type (positive/negative) reached κ = .70. A comparison of this perturbation-based analysis and last shot analyses shows significantly different results. Direct errors usually occur in the midcourt (56.4%), whereas most negative perturbations originate from the backcourt (40.0%). In contrast to direct winners, mostly originating from a smash (45.5%), most positive perturbations are created by net shots (30.1%). We argue that our method can be complementary to common last shot analyses and provides a possibility to describe players' strengths and weaknesses in more detail.

VIRD: Immersive Match Video Analysis for High-Performance Badminton Coaching

Badminton is a fast-paced sport that requires a strategic combination of spatial, temporal, and technical tactics. To gain a competitive edge at high-level competitions, badminton professionals frequently analyze match videos to gain insights and develop game strategies. However, the current process for analyzing matches is time-consuming and relies heavily on manual note-taking, due to the lack of automatic data collection and appropriate visualization tools. As a result, there is a gap in effectively analyzing matches and communicating insights among badminton coaches and players. This work proposes an end-to-end immersive match analysis pipeline designed in close collaboration with badminton professionals, including Olympic and national coaches and players. We present VIRD, a VR Bird (i.e., shuttle) immersive analysis tool, that supports interactive badminton game analysis in an immersive environment based on 3D reconstructed game views of the match video. We propose a top-down analytic workflow that allows users to seamlessly move from a high-level match overview to a detailed game view of individual rallies and shots, using situated 3D visualizations and video. We collect 3D spatial and dynamic shot data and player poses with computer vision models and visualize them in VR. Through immersive visualizations, coaches can interactively analyze situated spatial data (player positions, poses, and shot trajectories) with flexible viewpoints while navigating between shots and rallies effectively with embodied interaction. We evaluated the usefulness of VIRD with Olympic and national-level coaches and players in real matches. Results show that immersive analytics supports effective badminton match analysis with reduced context-switching costs and enhances spatial understanding with a high sense of presence.

Effects of plyometric training on measures of physical fitness in racket sport athletes: a systematic review and meta-analysis

Background

Over the past decade, the popularity of racket sports has surged. Plyometric training (PT) has been the focus of extensive research because of the proven benefits it provides to athletes. However, there is a lack of systematic reviews and meta-analyses specifically evaluating the impact of PT on physical fitness metrics in racket sport athletes. This study aimed to conduct a comprehensive review and analysis of evidence derived from randomized controlled trials (RCTs) to evaluate the effects of PT on measures of physical fitness among racket sports athletes.

Methods

The electronic databases PubMed, Web of Science, SCOPUS, and SPORTDiscus were systematically searched up to June 2023 without placing any restrictions on the publication dates. The PICOS method was adopted to establish the inclusion criteria: (a) healthy athletes who participate in racket sports; (b) a PT program; (c) a control group; (d) assessment of physical fitness components pre- and post-PT; and (e) RCTs. The records' methodological quality was assessed utilizing the Physiotherapy Evidence Database (PEDro) scale. The certainty in the evidence related to each outcome was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessment. A random-effects model was used to calculate effect sizes (ES; Hedges' g) between experimental and control groups.

Results

There were 14 eligible studies of moderate-to-high-quality, involving 746 athletes in total. The results revealed small-to-moderate effects (p < 0.05) of PT on muscle power (ES = 0.46), muscle strength (ES = 0.50), sprint speed (ES = 0.45), change of direction ability (ES = 0.76), and reaction time (ES = 0.67), while no clear evidence was found on balance and flexibility. The training-induced changes in muscle power showed no significant difference (p > 0.05) between youth (ES = 0.72) and adults (ES = 0.40). There were also similar muscle power improvements (ES = 0.36-0.54 vs 0.38-0.56, all p > 0.05) for a length of ≤7 weeks with ≤14 total PT sessions vs >7 weeks with >14 total PT sessions, and ≤2 weekly sessions vs >2 sessions. No adverse effects were reported in the included studies regarding the PT intervention. The certainty of evidence varied from very low to moderate. Conclusions: Our findings demonstrated that PT has positive effects on important indices of physical fitness among athletes participating in racket sports. Future studies are required to clarify the optimal doses and examine interactions among training variables to further promote the physical fitness of this specific population.

Cyclic relationship of mechanical likelihood: Coupling perception-action states in extended haptic accuracy

The present study investigates the dynamic nature of haptic accuracy in racket sports, specifically focusing on self-produced movements in participants with different skill levels (novice vs. expert). The study examines performance accuracy using indicators such as absolute error size and the coefficient of restitution as measures of haptic accuracy. To collect and analyze the data, custom-made devices, including shock and vibration sensors and Qualisys Track Manager, were used. The results indicate that skilled participants demonstrated higher accuracy, reflected by smaller absolute error sizes, and exhibited reduced variability in impulse vibration during self-produced movements. Moreover, employing maximum likelihood estimation and differential equations, we reveal cyclic relationships among these mechanical features. These findings provide valuable insights into perception-action coupling within different haptic skill levels, contributing to a comprehensive understanding of expertise in racket sports. By shedding light on the intricate relationship between haptic accuracy and performance, this research offers a valuable framework for studying perception-action coupling in racket sports and can potentially guide future investigations.

Analysis of Accumulated Workloads and Performance Testing Across a Collegiate Women's Lacrosse Season

ABSTRACT

Fields, JB, Kuhlman, NM, Jagim, AR, Dulak-Sigler, C, and Jones, MT. Analysis of accumulated workloads and performance testing across a collegiate women's lacrosse season. J Strength Cond Res 37(11): 2213-2221, 2023-Monitoring accumulated workloads, acute:chronic workload ratios (ACWR), and training monotony (TM) are practical methods for monitoring athlete physical stress. Performance testing provides useful information about the changing nature of physical abilities. Therefore, the purpose was to examine differences in accumulated workloads based on session type, explore seasonal trends in ACWR and TM, and assess changes in performance assessments in collegiate women's lacrosse athletes. Athletes, who were identified as starters ( n = 12), wore positional monitoring technology during training sessions ( n = 61) and games ( n = 17) and completed preseason and postseason assessments of speed, agility, power (jump tests), strength, aerobic capacity, and body composition. Separate 1-way analyses of variance were used to determine differences in accumulated workloads for session type and differences in performance assessments from preseason to postseason ( p < 0.05). When compared with games, practice sessions elicited greater ( p < 0.001) accumulated total distance, player load, repeated high-intensity efforts, accelerations, change of direction, explosive efforts, high-speed efforts ( p = 0.002), and high-speed distance ( p = 0.002). Throughout the season, ACWR and TM ranged from 0.16 to 1.40 AU and 0.68-1.69 AU, respectively. The 40-yd sprint ( p < 0.001) and pro-agility ( p < 0.001) improved from preseason to postseason, whereas no changes in aerobic capacity, lower-body power, or strength were observed ( p > 0.05). The monitoring of accumulated loads, ACWR and TM, and performance tests revealed novel information about the seasonal demands of collegiate women's lacrosse. Women lacrosse players are able to improve speed and agility throughout the season, while maintaining strength, power, and endurance, with minimal reductions in fat-free mass.

Teamwork makes the dream work: Testing for shared perceptions on psycho-behavioural skills between athletes, coaches and parents

Psycho-behavioural skills play a key role in optimising progression through talent development, and this study investigated to what extent athlete's self-perceptions align with those of their coaches and parents. Firstly, we examined if levels of alignment between these three raters differ across age of the athlete. To this end, 122 athletes between 9 and 18 years old (12.17 ± 2.41 years old; 47 gymnasts, 13 cyclists and 62 badminton players) completed a psycho-behavioural questionnaire. The ANOVA's indicated low levels of correspondence between the ratings of the athlete, the coach and the parents during childhood, while better levels of shared perceptions were found in adolescence. Secondly, we investigated to what extent coaches and parents believed their own perception of the athlete's and the perception of the athlete's psycho-behavioural skills were accurate. Parents appeared to be more confident in accurately perceiving the psycho-behavioural skills of the athlete than coaches. Parents and coaches also believed that older athletes would be more honest on their psycho-behavioural shortcomings than younger athletes. Altogether, these findings highlight that athletes and other stakeholders in the talent development environment should strive for better alignment in perceptions on psycho-behavioural skills during the talent development pathway. With better integrated perceptions, a more functional and efficient talent development system for the athlete targeting the psycho-behavioural skills can be created.

Comparing autoregulatory progressive resistance exercise and velocity-based resistance training on jump performance in college badminton athletes

Objectives

Jumping ability has been identified as a key factor that influences the performance of badminton athletes. Autoregulatory progressive resistance exercise (APRE) and velocity-based resistance training (VBRT) are commonly used approaches to enhance muscle strength and have been shown to accurately monitor the development of explosive power to improve jumping ability. This study aims to investigate the effects of APRE and VBRT on badminton athletes' jumping ability and to provide practical insights into improving their jumping performance during competitions.

Methods

Upon completing familiarization and pretesting, 18 badminton athletes were included and completed the training intervention (age, 21.4 ± 1.4 years; stature, 170.1 ± 7.3 cm; body mass, 65.9 ± 12 kg); they were randomly divided into the APRE group (n = 9) and VBRT group (n = 9). Jumping performance was assessed during the countermovement jump (CMJ), squat jump (SJ), and drop jump (DJ) via SmartJump, with CMJ 's and SJ's jump height, eccentric utilization ratio (EUR), and reactive strength index (RSI). All participants then completed a 4-week in-season resistance training intervention.

Results

(1) The results of the within-group indicated that only the CMJ (pre: 41.56 ± 7.84 vs post: 43.57 ± 7.85, p < 0.05) of the APRE group had significant differences, whereas the SJ, EUR, and RSI were not significantly different (p > 0.05). (2) The results of the intergroups revealed that all indicators had no significant differences (p > 0.05), but APRE had a moderate effect size on the improvement of the CMJ (η2 = 0.244) and EUR (η2 = 0.068) when compared with VBRT.

Conclusions

The results showed that, compared to VBRT, APRE can effectively improve the performance of the reactive athletes' lower limb explosive power in the CMJ in a shorter period of time. The findings indicate that APRE may be useful for coaches seeking to improve the CMJ performance of athletes in the short term.

Attention Load Regulates the Facilitation of Audio-Visual Information on Landing Perception in Badminton

Based on the role of the high temporal sensitivity of the auditory modality and the advantage of audio-visual integration in motion perception and anticipation, we investigated the effect of audio-visual information on landing perception in badminton through two experiments; and we explored the regulatory role of attention load. In this study, experienced badminton players were asked to predict the landing position of the shuttle under the conditions of video (visual) or audio-video (audio-visual) presentation. We manipulated flight information or attention load. The results of Experiment 1 showed that, whether the visual information was rich or not, that is, whether or not it contained the early flight trajectory, the addition of auditory information played a promoting role. The results of Experiment 2 showed that attention load regulated the facilitation of multi-modal integration on landing perception. The facilitation of audio-visual information was impaired under high load, meaning that audio-visual integration tended to be guided by attention from top to bottom. The results support the superiority effect of multi-modal integration, suggesting that adding auditory perception training to sports training could significantly improve athletes' performance.

Question Format Matters: Do Athletes Really Know the Signs and Symptoms of a Sport-Related Concussion?

Authors of previous studies commonly used a multiselect checklist method to assess an athlete's ability to recognize true sport-related concussion (SRC) signs and symptoms (S&S) among incorrect distractor options. However, this may overinflate the evaluation of participants' knowledge because the multiselect method does not test athletes' ability to retrieve knowledge from their long-term memory. To examine this hypothesis, we sent an online survey to registered members of the Japan Lacrosse Association (n = 8530) to assess differences in reported SRC S&S by open-ended-question and multiselect formats. We also evaluated whether previous exposure to SRC education and a history of SRC influenced athletes' SRC S&S knowledge. The numbers and proportions of responses were calculated using descriptive statistics. The Pearson correlation was calculated to analyze the relationship between scores from the 2 question formats. Unpaired-samples t tests were conducted to compare the mean scores for each question format by previous SRC education and history of diagnosed SRC. Odds ratios were computed to express the relationship between the proportion of correct answers by question format per symptom. The response rate of the survey was 35.9% (n = 3065), and scores from the 2 question formats were correlated (r = 0.34, 95% CI = 0.31, 0.37; P < .001). For both question formats, athletes with previous exposure to SRC education and a history of SRC had a greater number of correct answers; however, the mean differences were trivial. Researchers and clinicians should acknowledge the difference between multiselect (recognition) and open-ended (free recall) formats when assessing one's understanding of SRC and managing athletes with a suspected SRC.

Three-Dimensional Biomechanics of the Trunk and Upper Extremity During Overhead Throwing in Wheelchair Lacrosse Athletes With Spinal Cord Injury

OBJECTIVE

Quantify differences in overhead throwing kinematics between wheelchair lacrosse athletes with spinal cord injury and able-bodied lacrosse athletes.

DESIGN

This is a cross-sectional, prospective study. Motion analysis captured overhead throwing motions of five wheelchair lacrosse athletes with spinal cord injury and six able-bodied lacrosse athletes seated in a wheelchair and standing. Three-dimensional thorax and dominant arm sternoclavicular, acromioclavicular, glenohumeral, elbow, and wrist joint angles, ranges of motion, as well as angular velocities were computed using an inverse kinematics model. Nonparametric tests assessed group differences ( P < 0.05).

RESULTS

Participants with spinal cord injury exhibited less peak thorax axial rotation, ranges of motion, and angular velocity, as well as greater wrist flexion than able-bodied participants seated. Participants with spinal cord injury exhibited less peak thorax axial rotation and lateral bending, ranges of motion, and three-dimensional angular velocities; less peak two-dimensional sternoclavicular joint motion, ranges of motion, and peak angular velocities; less peak acromioclavicular joint protraction angular velocity; less glenohumeral joint adduction-abduction and internal-external rotation motion, ranges of motion, and angular velocities; and greater wrist flexion than able-bodied participants standing.

CONCLUSIONS

Kinematic differences were observed between groups, with athletes with spinal cord injury exhibiting less thorax and upper extremity joint motion and slower joint angular velocities than able-bodied athletes. This knowledge may provide insights for movement patterns and potential injury risk in wheelchair lacrosse.

How Accurate Are Coaches in Predicting Perceived Exertion of Their Athletes?

ABSTRACT

Ryan, GA, Bunn, JA, and Eisenman, ML. How accurate are coaches in predicting perceived exertion of their athletes? J Strength Cond Res 37(3): 684-687, 2023-Ratings of perceived exertion (RPE) are used extensively to subjectively evaluate workload in sport. The purpose of this study was to compare season long player to coach perceptions of RPE loads (RPEL) in Division I men's soccer and women's lacrosse programs. Coach and player self-reported RPE were collected during the competitive seasons for both teams within 30 minutes of training sessions. Scores of RPE were multiplied by recorded training time to determine RPEL and averaged to create a daily coach and player RPEL. Accuracy of RPEL prediction between coaches and players was determined via mean bias, mean absolute percent error (MAPE), correlation, and an equivalence test. Soccer coaches underestimated RPEL (1,345 ± 410 arbitrary unit [AU]) compared with players (1,372 ± 435 AU). The coach mean bias was -27.3 ± 151.9 AU, wieth an MAPE of 7.4%, a strong correlation (r = 0.937, p < 0.001), and coach to player equivalence (p = 0.045). Lacrosse coaches overestimated RPELs (876 ± 349 AU) compared with players (829 ± 214 AU). The coach mean bias was 47 ± 189 AU, with an MAPE of 14.7%, a strong correlation (r = 0.883, p < 0.001), and coach to player equivalence (p = 0.010). Analyses indicated that coaches accurately predicted player RPEL within both sports. Variance occurred on days with high RPELs, with overestimations occurring in lacrosse and underestimation in soccer. Coaches can use RPELs to assess subjective training load but should consider objective measures, including microtechnology, to provide a comprehensive assessment.

Badminton Improves Executive Function in Adults Living with Mild Intellectual Disability

BACKGROUND

Adults with intellectual disability have limited executive function-which includes working memory, cognitive flexibility, and inhibitory control subcomponents-making their ability to live independently challenging. The present study explored whether a badminton intervention program could improve the executive function of adults living with a mild intellectual disability, but with no physical disability.

METHODS

This randomized controlled study randomly assigned 30 adults with mild intellectual disabilities recruited from Shanghai Sunshine bases in Shanghai (20 males and 10 females; mean age, 35.80 (3.93) years) to a badminton intervention program (n = 15, training for 12 weeks, 3 times/week, 60 min each time) or the control group (n = 15), which received a typical physical education course consisting primarily of gymnastics. Correct response rates and response times on the Stroop test, n-back task, and task switching were analyzed using two-way analyses of variance, followed by simple effects tests to evaluate inhibitory control, working memory, and cognitive flexibility, respectively, before and after the badminton intervention.

RESULTS

No significant difference was detected between the badminton group and the control group (p > 0.05) for their pre-test scores on any subcomponent of executive function. A 2 × 2 repeated-measures analysis of variance showed a significant increase in accuracy in the inhibitory control task for the badminton group after the intervention (p < 0.05). In addition, the accuracy rate and reaction time in a working memory task were significantly improved in the badminton group after the intervention (p < 0.05). Although some improvement in cognitive flexibility was observed for this group after the intervention, it was not statistically significant (p > 0.05). In the control group, there was no significant difference in any executive function subcomponents after the intervention (p > 0.05).

CONCLUSIONS

These results suggest that badminton may be used as an effective intervention to improve the executive function of adults with a mild intellectual disability and that our protocol may inform future badminton exercise intervention programs.

Visual Behaviours of Expert Padel Athletes When Playing on Court: An In Situ Approach with a Portable Eye Tracker

Eye-tracking research has allowed the characterisation of gaze behaviours in some racket sports (e.g., tennis, badminton), both in controlled laboratory settings and in real-world scenarios. However, there are no studies about visual patterns displayed by athletes in padel.

METHOD

The aim of this exploratory case study was to address the visual behaviours of eight young expert padel athletes when playing match games on a padel court. Specifically, their gaze behaviours were examined with an in situ approach while returned trays/smashes, serves, and volleys were performed by their counterparts. Gaze patterns were registered with an SMI Eye Tracking Glasses 2 Wireless.

RESULTS

The participants' gaze was mainly focused on the ball-flight trajectory and on the upper body of the opponents because they were the two visual locations with a larger number of fixations and longer fixation time. No differences were found in these variables for each type of visual location when the three return situations were compared, or independently of them.

CONCLUSIONS

Padel players displayed a similar gaze behaviour during different representative return situations. This visual pattern was characterised by fixating at the ball and some opponents' upper kinematics (head, shoulders, trunk, and the region of arm-hand-racket) to perform real interceptive actions while playing against them on a padel court.

A lateral ankle sprain during a lateral backward step in badminton: A case report of a televised injury incident

BACKGROUND

This study presents a kinematic analysis of an acute lateral ankle sprain incurred during a televised badminton match. The kinematics of this injury were compared to those of 19 previously reported cases in the published literature.

METHODS

Four camera views of an acute lateral ankle sprain incurred during a televised badminton match were synchronized and rendered in 3-dimensional animation software. A badminton court with known dimensions was built in a virtual environment, and a skeletal model scaled to the injured athlete's height was used for skeletal matching. The ankle joint angle and angular velocity profiles of this acute injury were compared to the summarized findings from 19 previously reported cases in the published literature.

RESULTS

At foot strike, the ankle joint was 2° everted, 33° plantarflexed, and 18° internally rotated. Maximum inversion of 114° and internal rotation of 69° was achieved at 0.24 s and 0.20 s after foot strike, respectively. After the foot strike, the ankle joint moved from an initial position of plantarflexion to dorsiflexion-from 33° plantarflexion to 53° dorsiflexion (range = 86°). Maximum inversion, dorsiflexion, and internal rotation angular velocity were 1262°/s, 961°/s, and 677°/s, respectively, at 0.12 s after foot strike.

CONCLUSION

A forefoot landing posture with a plantarflexed and internally rotated ankle joint configuration could incite an acute lateral ankle sprain injury in badminton. Prevention of lateral ankle sprains in badminton should focus on the control and stability of the ankle joint angle during forefoot landings, especially when the athletes perform a combined lateral and backward step.

A Query Language for Exploratory Analysis of Video-Based Tracking Data in Padel Matches

Recent advances in sensor technologies, in particular video-based human detection, object tracking and pose estimation, have opened new possibilities for the automatic or semi-automatic per-frame annotation of sport videos. In the case of racket sports such as tennis and padel, state-of-the-art deep learning methods allow the robust detection and tracking of the players from a single video, which can be combined with ball tracking and shot recognition techniques to obtain a precise description of the play state at every frame. These data, which might include the court-space position of the players, their speeds, accelerations, shots and ball trajectories, can be exported in tabular format for further analysis. Unfortunately, the limitations of traditional table-based methods for analyzing such sport data are twofold. On the one hand, these methods cannot represent complex spatio-temporal queries in a compact, readable way, usable by sport analysts. On the other hand, traditional data visualization tools often fail to convey all the information available in the video (such as the precise body motion before, during and after the execution of a shot) and resulting plots only show a small portion of the available data. In this paper we address these two limitations by focusing on the analysis of video-based tracking data of padel matches. In particular, we propose a domain-specific query language to facilitate coaches and sport analysts to write queries in a very compact form. Additionally, we enrich the data visualization plots by linking each data item to a specific segment of the video so that analysts have full access to all the details related to the query. We demonstrate the flexibility of our system by collecting and converting into readable queries multiple tips and hypotheses on padel strategies extracted from the literature.

A study on the assessment and scoring standard of badminton course in colleges and universities: A review

With the continuous promotion of quality education, the importance of physical education in college teaching is increasingly prominent. In order to meet the sports needs of different students, badminton courses are introduced in colleges and universities. Badminton not only has a strong entertainment, but also a good physical exercise, loved by students. However, due to the existing badminton class evaluation standard is not scientific and reasonable, which is not conducive to the smooth implementation of physical education, this paper studies the current situation of badminton assessment and scoring standards, points out the existing problems in the teaching process, and gives a new way to improve the assessment and scoring standards of badminton in colleges and universities, in order to provide reference for the assessment system of badminton in colleges and universities, and then improve the teaching effect of badminton.

Correlation of Lower Limb Muscle Activity with Knee Joint Kinematics and Kinetics during Badminton Landing Tasks

A study on a single-leg landing task after an overhead stroke in badminton suggests that poor knee biomechanical indicators may be a risk factor for anterior cruciate ligament (ACL) injury. A preventive program targeting neuromuscular control strategies is said to alter the biomechanics of the knee joint and have a beneficial effect on reducing ACL injury. However, the relationship between muscle activity around the knee joint and knee biomechanical risk factors in the badminton landing task is unclear. The purpose of this study was to investigate the relationship between this movement pattern of muscle activity and knee kinematics and kinetics. This experiment analyzed knee muscle activity and biomechanical information in a sample of 34 badminton players (17 male, 17 female) during a badminton landing task. We assessed the relationship between the rectus femoris (RF), medial hamstring (MHAM), lateral hamstring (LHAM), medial gastrocnemius (MGAS), lateral gastrocnemius (LGAS), medial and lateral hamstring to quadriceps co-contraction ratio (MH/Q and LH/Q) with the knee flexion angle, valgus angle, extension moment, valgus moment, and proximal tibial anterior shear force. A moderate negative correlation was found between the peak knee flexion angle and electromyography (EMG) activity in LGAS (r = 0.47, p = 0.0046, R² = 0.23, 95% CI: 0.16 to 0.70). Peak proximal tibial shear force showed strong and positive correlations with RF EMG activity (r = 0.52, p = 0.0016, R² = 0.27, 95% CI: 0.22 to 0.73) and strong and negative correlations with MH/Q (r = 0.50, p = 0.0023, R² = 0.25, 95% CI: 0.20 to 0.72). The knee extension moment showed moderate and positive correlations with RF EMG activity (r = 0.48, p = 0.0042, R² = 0.23, 95% CI: 0.17 to 0.70) and strong and negative correlations with MH/Q (r = 0.57, p = 0.0004, R² = 0.33, 95% CI: 0.29 to 0.76). The peak knee valgus moment showed strong and positive correlations with LH/Q (r = 0.55, p = 0.0007, R² = 0.31, 95% CI: 0.26 to 0.75). Our findings suggest that there is a correlation between lower extremity muscle activity and knee kinematics and kinetics during the single-leg landing task in badminton; therefore, lower extremity muscle activity should be considered when developing rehabilitation or injury prevention programs.

Effect of balance training on footwork performance in badminton: An interventional study

Badminton is a racket sport that requires a wide variety of proficient postural changes and moves including jumps, lunges, quick changes in direction, and rapid arm movements. Efficient movement in badminton court entails reaching the shuttlecock in as few steps as possible while maintaining good balance. Balance training is an unexplored component in badminton training protocol, though balance is important in injury prevention and performance enhancement. We aimed to investigate the effectiveness of balance training on sport-specific footwork performance of school-level competitive badminton players. We conducted a controlled trial involving 20 male badminton players (age 12.85±0.67 years). Participants were stratified according to their level of performance in the game, and payers from each stratum were randomly assigned to control and intervention groups. The control group (n = 8) engaged in 2 hours of ordinary badminton training, whereas the intervention group (n = 12) underwent 30 minutes of balance training followed by 1 hour and 30 minutes of ordinary badminton training, 2 days per week for 8 weeks. We tested the participants at baseline and after 8 weeks for static balance (Unipedal Stance Test), dynamic balance (Star Excursion Balance Test) and sport-specific footwork performance (shuttle run time and push-off times during stroke-play). On pre- vs. post-intervention comparisons, both groups improved in static balance (eyes opened) (p<0.05), but only the intervention group improved in dynamic balance (p = 0.036) and shuttle-run time (p = 0.020). The intervention group also improved push-off times for front forehand (p = 0.045), side forehand (p = 0.029) and rear around-the-head shots (p = 0.041). These improvements in push-off times varied between 19-36% of the baseline. None of the footwork performance measures significantly improved in the control group. Our findings indicate that incorporating a 30-minute balance training program into a regular training schedule improves dynamic balance, and on-court sport-specific footwork performance in adolescent competitive badminton players, after 8 weeks of training.

Automatic Shuttlecock Fall Detection System in or out of a Court in Badminton Games-Challenges, Problems, and Solutions from a Practical Point of View

We built an Instant Review System (IRS) for badminton, also named a Challenge System. It allows players to verify linesmen in/out decisions and makes the game fairer. Elements such as lighting, the influence of air-conditioning on the flight trajectory, or the moving mats can significantly impact the final in/out decision. Due to the construction of the shuttlecock, it behaves differently during the flight than, for example, a tennis ball. This publication discusses the problems we encountered during our work with the proposed solution. We present the evolution of the system's architecture: the first version with the cameras mounted above the court and placed around the court close to the lines, tracking the shuttlecock in 3D; and the second, improved version with cameras placed only around the court, without 3D reconstruction. We used our system during the BWF World Senior Badminton Championships in Katowice. We present the system's results from this tournament and compare them with linesmen's decisions. We describe the system's verification process by the Badminton World Federation and Polish Badminton Federation and discuss evaluation methods for such systems. Our solution is comparable to the commercial product used in the biggest badminton tournaments in regard to processing time and accuracy. Still, our architecture and algorithms make installing it much easier and faster, making the system more adaptive, reliable, flexible, and universal in relation to the practical requirements of sports halls.

Risk Factors for, and Prediction of, Shoulder Pain in Young Badminton Players: A Prospective Cohort Study

BACKGROUND

Shoulder pain (SP) caused by hitting the shuttlecock is common in young badminton players. The objectives of the present study were to predict the risk factors for SP in young badminton players, and to determine the optimal risk factor cut-off that best discriminates those players who are at higher risk of suffering from SP.

METHODS

A prospective cohort study was conducted with 45 under-17 badminton players who participated in the Spanish Championship. Data were collected on anthropometric age, sports history, sagittal spinal curves, range of motion (ROM) and maximum isometric strength of shoulder. After 12 months, players completed a SP history questionnaire. Bayesian Student's t-analysis, binary logistic regression analysis and ROC analysis were performed.

RESULTS

Overall, 18 (47.4%) players reported at least one episode of SP. The shoulder internal rotation (SIR) ROM showed the strongest association (OR = 1.122; p = 0.035) with SP. The SIR ROM has an excellent ability to discriminate players at increased risk for SP (p = 0.001). The optimal cut-off for SIR ROM, which predicts players with an 81% probability of developing SP, was set at 55° (sensitivity = 75.0%, specificity = 83.3%).

CONCLUSIONS

The young badminton players who had a shoulder internal rotation ROM of 55° or less have a higher risk of SP one year later.

Analysis of Functional Arch Support Insoles on the Biomechanics and Performance in Right-Forward Lunging Step of Badminton Players

The purpose of this study was to examine the differences in biomechanical parameters and sports-specific performance of lower limbs between arch support insoles (ASI) and flat insoles (FLI) when performing net strides. After installing the MVN IMU system, 18 college badminton team members were asked to take the following tests: (1) Consecutive net stride tests; (2) Six-point footwork tests; (3) Retrieve/stroke the ball at the left and right net; (4) Smash and retrieve/stroke the ball at the net; (5) Smash at the front and back crossover step. The joint angle of the lower limbs and ground reaction force during the support phase was collected. The results demonstrated that the peak right hip flexion angle was significantly greater with ASI than FLI (63.09 ± 10.70; 60.08 ± 13.82; p = 0.028), while the peak right foot inversion angle was significantly smaller with ASI than FLI (20.68 ± 7.87; 23.85 ± 8.11; p = 0.013). The principal conclusion was that the arch support insole avoids the decrease in the hip flexion angle and the increase in the foot inversion angle during the net stride tests.

Data Collection Procedures and Injury Definitions in Badminton: A Consensus Statement According to the Delphi Approach

ABSTRACT

Previous studies involving injury surveillance in badminton players have used nonstandardized injury definitions and data collection methodologies. The purpose of this study was to apply a Delphi method to (1) reach a consensus on an injury definition in badminton and (2) develop a standardized badminton injury report form. An Injury Consensus Group was established under the auspices of the Badminton World Federation, and initial injury definitions and injury report form were developed. An internal panel was formed from the Injury Consensus Group, and an external panel was selected based on a combination of profession, experience in the field, sport-specific knowledge/expertise, and geographical location to obtain a widely representative sample. Through 2 rounds of voting by the external panel, consensus was reached on both the definition of an injury in badminton and a standardized injury report form. The agreed injury definition was "Any physical injury sustained by a player during a match or training regardless if further diagnostic tests were done or if playing time was lost" and the injury report form contained the following 7 sections: Injury record, Diagnosis, Injury mechanism, Regarding pain, Pain and return to play/training after injury, Grade of severity, and Recurrence. We recommend the use of the definitions and methods presented in this consensus statement for the reporting of injury in all international and domestic badminton players. This should make future injury surveillance reports directly comparable and hence more informative in recognizing trends over time and differences between countries.

The Effect of Sex, Sport, and Preexisting Histories on Baseline Concussion Test Performance in College Lacrosse and Soccer Athletes

OBJECTIVE

To study sex and sport differences in baseline clinical concussion assessments. A secondary purpose was to determine if these same assessments are affected by self-reported histories of (1) concussion; (2) learning disability; (3) anxiety and/or depression; and (4) migraine.

DESIGN

Prospective cohort.

SETTING

National Collegiate Athletic Association D1 Universities.

PARTICIPANTS

Male and female soccer and lacrosse athletes (n = 237; age = 19.8 ± 1.3 years).

ASSESSMENT OF RISK FACTORS

Sport, sex, history of (1) concussion; (2) learning disability; (3) anxiety and/or depression; and (4) migraine.

MAIN OUTCOME MEASURES

Sport Concussion Assessment Tool 22-item symptom checklist, Standardized Assessment of Concussion, Balance Error Scoring System (BESS), Generalized Anxiety Disorder 7-item scale, and Patient Health Questionnaire.

RESULTS

Female athletes had significantly higher total symptoms endorsed (P = 0.02), total symptom severity (P < 0.001), and BESS total errors (P = 0.01) than male athletes. No other sex, sport, or sex-by-sport interactions were observed (P > 0.05). Previous concussion and migraine history were related to greater total symptoms endorsed (concussion: P = 0.03; migraine: P = 0.01) and total symptom severity (concussion: P = 0.04; migraine: P = 0.02). Athletes with a migraine history also self-reported higher anxiety (P = 0.004) and depression (P = 0.01) scores. No other associations between preexisting histories and clinical concussion outcomes were observed (P > 0.05).

CONCLUSIONS

Our findings reinforce the need to individualize concussion assessment and management. This is highlighted by the findings involving sex differences and preexisting concussion and migraine histories.

CLINICAL RELEVANCE

Clinicians should fully inventory athletes' personal and medical histories to better understand variability in measures, which may be used to inform return-to-participation decisions following injury.

Adjusted Landing Technique Reduces the Load on the Achilles Tendon in Badminton Players

Achilles tendon (AT) rupture is common among recreational male badminton players. We hypothesize that a landing technique following forehand jump strokes with the landing foot in a neutral position often performed by recreational players and occasionally by elite players may expose the AT to higher loads than a scissor kick jump (SKJ) technique with the leg/foot externally rotated. The study aimed to investigate if recreational players could reduce the load in the AT when adopting the SKJ technique compared to their habitual landing technique with the foot in a neutral position and secondarily to compare the AT force between recreational players and elite players. Ten recreational male players performed simulated jump strokes in a biomechanical laboratory using both their original technique and the SKJ technique traditionally used by elite players. For comparison reasons ten elite players performed SKJs. Landing kinematics and AT forces were captured and calculated using 3D movement analysis. The landing leg was more externally rotated in the recreational players' adjusted technique (78 ± 10 degrees, p < 0.001) compared to 22 ± 21 degrees in recreational players' original technique. The peak AT force of the recreational players was significantly higher for the original technique compared to the adjusted technique (68 ± 19 N/kg vs. 50 ± 14 N/kg, p = 0.005). Additionally, the peak AT forces observed during the recreational players' original technique was higher, though not significantly, than those observed for elite players (55 ± 11 N/kg, p = 0.017). / = 0.016 due to a Bonferroni correction. These findings indicate that recreational badminton players that normally land with the foot in a neutral position, may reduce their AT load by 25% when adopting the SKJ technique of elite players and land with the leg/foot in an externally rotated position.

The Role of Padel in Improving Physical Fitness and Health Promotion: Progress, Limitations, and Future Perspectives—A Narrative Review

Benefits of regular exercise for health are beyond any doubt. However, adherence to regular physical activity is an ongoing challenge. Among the options for exercise engagement, racket sports, and particularly padel, stand as emerging practices for children and adults to have fun, improve physical fitness, and potentially develop motor and cognitive skills. In the last decade, the literature on padel is increasing exponentially. However, there is a need for further experimental research. To design safe and effective sport-base physical activity promotion interventions, it is essential to have a deep understanding of the physical requirements, technical complexity, injury risks, and strength and conditioning programs. To assist researchers to conduct effective padel-based interventions for health, this review summarizes the state-of-the-art evidence about padel, identifies key topics to be addressed in the future, and discusses the potential role of padel as a physical fitness and health promotion strategy. A narrative review is presented, summarizing the results of padel articles from three different databases: Web of Science, Scopus, and Google Scholar. Studies written in Spanish and English were the inclusion criteria. The studies had to be published from 2000 onwards and be original, as well as peer-reviewed.

Short-Term Effects of Low-Fat Chocolate Milk on Delayed Onset Muscle Soreness and Performance in Players on a Women's University Badminton Team

This study investigated the short-term effects of low-fat chocolate milk (LFCM) consumption on delayed onset muscle soreness (DOMS) and performance in female badminton players. Seven female badminton players (23 ± 1 years; height: 163.8 ± 4.1 cm; body mass: 58.7 ± 0.9 kg) were randomly assigned to 1 week of LFCM (500 mL) or placebo (water, 500 mL) consumption in a crossover design. Participants consumed LFCM or water immediately after each training session during the 1-week intervention. Performance variables (aerobic power, anaerobic power, agility, explosive power, and maximum handgrip strength) were assessed at two separate time points: pre and post-intervention (after 1 week). In addition, the Visual Analogue Scale (VAS) was used to assess DOMS before, immediately after, and at 24 and 48 h after each training session. There were significant time effects for aerobic power, upper body explosive power, minimum anaerobic power, and time to exhaustion (TTE), which significantly increased after LFCM consumption (p < 0.05). Moreover, relative and maximum lower body power significantly (p < 0.05) increased, while rating of perceived exertion (RPE) as well as DOMS in lower extremity muscles immediately after exercise significantly decreased after LFCM consumption compared to placebo (p < 0.05). There were no significant changes in maximum anaerobic power, agility, and maximum handgrip strength (p > 0.05). LFCM, as a post-exercise beverage, may help speed recovery in female badminton players leading to increased aerobic, anaerobic, and strength performance indices, increased TTE, and decreased muscle soreness and RPE.

Experimental Research on Badminton Teaching of Physical Education Major Based on Deep Learning in the Multimedia Environment

There are many problems in the routine badminton teaching; there are mainly three aspects in college teaching. One is that the hardware equipment related to badminton is not enough; the second is that the badminton teaching does not meet the educational goals; the third is that the participation of college students is not high, which is no longer suitable for the current practical teaching. In order to improve the teaching method of badminton and improve the students' special performance of badminton, this paper studies the teaching of badminton based on multimedia environment. 82 students majoring in badminton were randomly divided into two classes. The experimental class (n = 41) used multimedia badminton teaching, and the control class (n = 41) used traditional badminton teaching, which lasted for one semester. Before and after the experiment, the students' physical fitness and badminton performance were tested. And the two classes of students were to send questionnaires to investigate interest in learning badminton and teaching satisfaction. The results of standing long jump, 50 m, and 800 m of the experimental class were improved by 0.2 m, 1.13s, and 16.25s, respectively. This shows that the physical quality and badminton performance of the experimental class under the multimedia environment are better than those of the control class under the general teaching. In the experimental class, 16 students are very interested in learning badminton, and 22 students are very satisfied with the multimedia teaching method; in the control class, only 9 students are very interested in learning badminton, and only 13 students are very satisfied with the traditional teaching method, which shows that the interest and satisfaction of students in the experimental class under the multimedia environment are higher than those in the control class under the traditional teaching.

Experience-Dependent Modulation of Rubber Hand Illusion in Badminton Players

Badminton players have a plastic modification of their arm representation in the brain due to the prolonged use of their racket. However, it is not known whether their arm representation can be altered through short-term visuotactile integration. The neural representation of the body is easily altered when multiple sensory signals are integrated in the brain. One of the most popular experimental paradigms for investigating this phenomenon is the "rubber hand illusion." This study was designed to investigate the effect of prolonged use of a racket on the modulation of arm representation during the rubber hand illusion in badminton players. When badminton players hold the racket, their badminton experience in years is negatively correlated with the magnitude of the rubber hand illusion. This finding suggests that tool embodiment obtained by the prolonged use of the badminton racket is less likely to be disturbed when holding the racket.

The Effect of 6-Week Combined Balance and Plyometric Training on Dynamic Balance and Quickness Performance of Elite Badminton Players

The study aimed to investigate the effect of combined balance and plyometric training on dynamic balance and quickness performance of elite badminton athletes. Sixteen elite male badminton players volunteered to participate and were randomly assigned to a balance-plyometric group (PB: n = 8) and plyometric group (PT: n = 8). The PB group performed balance combined with plyometric training three times a week over 6 weeks (40 min of plyometrics and 20 min of balance training); while the PT group undertook only plyometric training for the same period (3–4 sets × 8–12 reps for each exercise). Both groups were given the same technical training (badminton techniques for 6 days a week). The dynamic stability and quick movement ability were assessed at baseline and after the intervention by measuring the performance of dynamic posture stability test (DPSI and COP), T-running test and hexagon jump test. The results showed that compared to PT, PB induced significantly greater improvements in F-DPSI, L-DPSI (p = 0.003, 0.025, respectively), F-COPAP, F-COPML, F-COPPL, L-COPPL (p = 0.024, 0.002, 0.029, 0.043, respectively), T-running test and hexagon jump test (p < 0.001). The change in L-DPSI, L-COPAP, L-COPML did not differ between PB and PT (p > 0.907). The findings suggest that combined training holds great promise of improving the dynamic balance and quickness performance in elite badminton athletes.

TIVEE: Visual Exploration and Explanation of Badminton Tactics in Immersive Visualizations

Tactic analysis is a major issue in badminton as the effective usage of tactics is the key to win. The tactic in badminton is defined as a sequence of consecutive strokes. Most existing methods use statistical models to find sequential patterns of strokes and apply 2D visualizations such as glyphs and statistical charts to explore and analyze the discovered patterns. However, in badminton, spatial information like the shuttle trajectory, which is inherently 3D, is the core of a tactic. The lack of sufficient spatial awareness in 2D visualizations largely limited the tactic analysis of badminton. In this work, we collaborate with domain experts to study the tactic analysis of badminton in a 3D environment and propose an immersive visual analytics system, TIVEE, to assist users in exploring and explaining badminton tactics from multi-levels. Users can first explore various tactics from the third-person perspective using an unfolded visual presentation of stroke sequences. By selecting a tactic of interest, users can turn to the first-person perspective to perceive the detailed kinematic characteristics and explain its effects on the game result. The effectiveness and usefulness of TIVEE are demonstrated by case studies and an expert interview.

TacticFlow: Visual Analytics of Ever-Changing Tactics in Racket Sports

Event sequence mining is often used to summarize patterns from hundreds of sequences but faces special challenges when handling racket sports data. In racket sports (e.g., tennis and badminton), a player hitting the ball is considered a multivariate event consisting of multiple attributes (e.g., hit technique and ball position). A rally (i.e., a series of consecutive hits beginning with one player serving the ball and ending with one player winning a point) thereby can be viewed as a multivariate event sequence. Mining frequent patterns and depicting how patterns change over time is instructive and meaningful to players who want to learn more short-term competitive strategies (i.e., tactics) that encompass multiple hits. However, players in racket sports usually change their tactics rapidly according to the opponent's reaction, resulting in ever-changing tactic progression. In this work, we introduce a tailored visualization system built on a novel multivariate sequence pattern mining algorithm to facilitate explorative identification and analysis of various tactics and tactic progression. The algorithm can mine multiple non-overlapping multivariate patterns from hundreds of sequences effectively. Based on the mined results, we propose a glyph-based Sankey diagram to visualize the ever-changing tactic progression and support interactive data exploration. Through two case studies with four domain experts in tennis and badminton, we demonstrate that our system can effectively obtain insights about tactic progression in most racket sports. We further discuss the strengths and the limitations of our system based on domain experts' feedback.

Training-Associated Superior Visuomotor Integration Performance in Elite Badminton Players after Adjusting for Cardiovascular Fitness

Badminton is recognized as the fastest racket sport in the world based on the speed of the birdie which can travel up to 426 km per hour. On the badminton court, players are not only required to track the moving badminton birdie (visual tracking and information integration) but also must anticipate the exact timing to hit it back (temporal estimation). However, the association of training experience related to visuomotor integration or temporal prediction ability remains unclear. In this study, we tested this hypothesis by examining the association between training experience and visuomotor performances after adjusting for age, education, and cardiovascular fitness levels. Twenty-eight professional badminton players were asked to perform a compensatory tracking task and a time/movement estimation task for measuring visuomotor integration and temporal prediction, respectively. Correlation analysis revealed a strong association between training experience and performance on visuomotor integration, indicating badminton training may be promoted to develop visuomotor integration ability. Furthermore, the regression model suggests training experience explains 32% of visuomotor integration performances. These behavioral findings suggest badminton training may facilitate the perceptual-cognitive performance related to visuomotor integration. Our findings highlight the potential training in visuomotor integration may apply to eye-hand coordination performance in badminton sport.

Epidemiology of Injuries in Elite Badminton Players: A Prospective Study

OBJECTIVE

To determine the incidence and characteristics of injuries in elite badminton players over a competitive season.

DESIGN

Prospective cohort study.

SETTING

The French National Institute of Sport, Expertise, and Performance (INSEP).

PARTICIPANTS

Twenty international elite badminton players.

INDEPENDENT VARIABLES

The type, the location, the occurrence of the injury (match or training), the footwork type, the type of shot, and the perceived fatigue were collected.

MAIN OUTCOME MEASURES

Injury incidence rates were calculated per 1000 hours of play (Hop).

RESULTS

Thirty-five injuries were collected over 10 210 hours of player exposure with an overall incidence rate of 3.4 injuries per 1000 Hop, with higher incidence during matches than training (11.6 vs 2.08; P < 0.05). Lower-limb injuries (LLI) were the most frequent (54.3%) especially on the foot (22.9%), and upper-limb injury rate (37.1%) was higher compared with previous studies. The most common type was musculotendinous injuries (51.4%). The smash and the lunge were the most frequent causes of upper-limb injury and LLI, respectively. Injuries occurred mostly during the first third of play (46.2%).

CONCLUSIONS

This is the first prospective study to investigate badminton injuries among international badminton players. Further studies are needed to confirm our results on larger samples.

AIR-BT, a new badminton-specific incremental easy-to-use test

Background

Badminton is a highly demanding sport characterized by intermittent efforts with energy being provided by both the aerobic and anaerobic systems. To date, no incremental badminton field test has been developed that can be easily used by badminton coaches that requires accessible material for anyone.

Objectives

The purpose of this study was to develop a practical and reliable easy-to use intermittent endurance badminton test for estimating maximal oxygen uptake (VO_2max).

Methods

Thirty six Spanish badminton players (age: 24.1±10.3 years) performed, on different days of the same week, four incremental protocols to exhaustion in randomized order: a treadmill incremental test, a Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1) and twice the Abian intermittent recovery badminton test (AIR-BT). Oxygen uptake was determined with a breath-by-breath gas analyzer during the incremental treadmill test, and performance in the Yo-yo IR1 and AIR-BT was recorded.

Results

Significant correlations (p<0.001) for Pearson’s product moment coefficient were found between the performance in the AIR-BT and the two non-specific incremental tests (VO_2max in the Treadmill Test: r = 0.87, distance in the Yo-Yo IR1: r = 0.86). The regression equation to calculate the VO_2max from the AIR-BT time [VO_2max = 0.023*(AIR-BT time in seconds)+31.334] showed an adjusted R² of 0.76 and a SEE of 3.34 ml·kg^-1·min^-1. There was no significant difference between VO_2max obtained by the incremental treadmill test and VO_2max calculated using the regression equation (p = 0.644). A paired t-test reported no significant differences between day 1 and day 2 in the AIR-BT time (p = 0.753), the Pearson correlation coefficient between both days was: r = 0.88 (p<0.001) and the intraclass correlation coefficient was 0.875.

Conclusions

The AIR-BT is a valid and reliable on-court test for assessing VO_2max in badminton players and may be utilized by coaches and physical trainers for cross-sectional comparison of players and for evaluation of longitudinal changes.

Comparing Biomechanical Time Series Data During the Hang-Power Clean and Jump Shrug

ABSTRACT

Kipp, K, Comfort, P, and Suchomel, TJ. Comparing biomechanical time series data during the hang-power clean and jump shrug. J Strength Cond Res 35(9): 2389-2396, 2021-The purpose of this study was to investigate differences in the force-, velocity-, displacement-, and power-time curves during the hang-power clean (HPC) and the jump shrug (JS). To this end, 15 male lacrosse players were recruited from a National Collegiate Athletic Association Division-I team, and performed one set of 3 repetitions of the HPC and JS at 70% of their HPC 1 repetition maximum (1RM HPC). Two in-ground force plates were used to measure the vertical ground reaction force (GRF) and calculate the barbell-lifter system mechanics during each exercise. The time series data were normalized to 100% of the movement phase, which included the initial countermovement and extension phases, and analyzed with curve analysis and statistical parametric mapping (SPM). The SPM procedure highlighted significant differences in the force-time curves of the HPC and JS between 85 and 100% of the movement phase. Likewise, the SPM procedure highlighted significant differences in the velocity- and power-time curve of the HPC and JS between 90 and 100% of the movement phase. For all comparisons, performance of the JS was associated with greater magnitudes of the mechanical outputs. Although results from the curve analysis showed significant differences during other periods of the movement phase, these differences likely reflect statistical issues related to the inappropriate analysis of time series data. Nonetheless, these results collectively indicate that when compared with the HPC, execution of the JS is characterized by greater GRF and barbell-lifter system velocity and power outputs during the final 10% of the movement phase.

Evaluation of Open-Source and Pre-Trained Deep Convolutional Neural Networks Suitable for Player Detection and Motion Analysis in Squash

In sport science, athlete tracking and motion analysis are essential for monitoring and optimizing training programs, with the goal of increasing success in competition and preventing injury. At present, contact-free, camera-based, multi-athlete detection and tracking have become a reality, mainly due to the advances in machine learning regarding computer vision and, specifically, advances in artificial convolutional neural networks (CNN), used for human pose estimation (HPE-CNN) in image sequences. Sport science in general, as well as coaches and athletes in particular, would greatly benefit from HPE-CNN-based tracking, but the sheer amount of HPE-CNNs available, as well as their complexity, pose a hurdle to the adoption of this new technology. It is unclear how many HPE-CNNs which are available at present are ready to use in out-of-the-box inference to squash, to what extent they allow motion analysis and if detections can easily be used to provide insight to coaches and athletes. Therefore, we conducted a systematic investigation of more than 250 HPE-CNNs. After applying our selection criteria of open-source, pre-trained, state-of-the-art and ready-to-use, five variants of three HPE-CNNs remained, and were evaluated in the context of motion analysis for the racket sport of squash. Specifically, we are interested in detecting player's feet in videos from a single camera and investigated the detection accuracy of all HPE-CNNs. To that end, we created a ground-truth dataset from publicly available squash videos by developing our own annotation tool and manually labeling frames and events. We present heatmaps, which depict the court floor using a color scale and highlight areas according to the relative time for which a player occupied that location during matchplay. These are used to provide insight into detections. Finally, we created a decision flow chart to help sport scientists, coaches and athletes to decide which HPE-CNN is best for player detection and tracking in a given application scenario.

Indoor air quality investigation of a badminton hall in humid season through objective and subjective approaches

This study investigated the indoor air quality (IAQ) during humid season in an old badminton hall, to explore the IAQ characteristics of natural ventilated sports buildings for public use. The indoor air parameters (temperature, relative humidity and air velocity) and indoor air pollutants (CO₂, TVOC, PM_2.5 and PM₁₀) were measured. A subjective approach was carried out through questionnaire survey. 185 valid questionnaires were recovered, and 68.7% of the participants had exercised. Results show that the indoor air qualities obtained through objective and subjective approaches were obviously different. Indoor PM, TVOC and CO₂ concentrations were normal, but 37.3% of the participants complained about the building materials' smell and 73.5% of the participants reported obvious sweaty odor. Physical activity might reduce a person's sensitivity to the environment. The participants generally felt warm and hot because of the high relative humidity. Post-exercise participants felt significantly hotter than those who did not exercise, and were generally more receptive to IAQ. The method of Fanger was employed to narrow the gap between subjective and objective approaches with a modified parameter, and to furtherly estimate the ventilation. The present study demonstrates the necessity to combine two approaches together to assess the IAQ in sports buildings.

Effects of Probiotics on Anxiety, Stress, Mood and Fitness of Badminton Players

Background: Reports of probiotic consumption on athletes’ performance are debatable due to their equivocal results. There is a need for more evidence on the effects of probiotic intake on psychological state and fitness level. Thus, this study determined the effects of daily probiotic consumption on competitive anxiety, perceived stress and mood among university badminton players, besides their fitness like aerobic capacity, strength, speed, leg power and agility. Methods: Thirty university badminton players aged from 19 to 22 years old were randomly divided equally into two groups, where the probiotic group (PG; n = 15) received a drink that contained Lactobacillus casei Shirota (3 × 10¹⁰ CFU) and placebo group (CG; n = 15) a placebo drink for six weeks. Anxiety, stress and mood levels were determined using the CSAI-2R, PSS and BRUMS questionnaires, respectively. Fitness levels were measured using by subjecting the players to 20-m shuttle runs (aerobic capacity), handgrips (muscular strength), vertical jumps (leg power), 40-m dash (speed) and T-test (agility). The Student’s t-test (p < 0.05) was used to determine the differences between PG and CG players. Results: After six weeks, the anxiety and stress levels of PG players significantly decreased by 16% (p < 0.001) and 20% (p < 0.001), respectively, but there were no significant changes detected in CG players. Supplementation of probiotics also improved aerobic capacity in PG players by 5.9% (p < 0.001) but did not influence the speed, strength, leg power and agility. Conclusions: Probiotics supplementation showed improved aerobic capacity and relieve anxiety and stress. However, further studies need to be carried out to determine the mechanisms through which probiotic intake produces these effects.

Structural and mechanical properties of the Achilles tendon in senior badminton players: Operated vs. non-injured tendons

BACKGROUND

The aim of this study was to describe the differences in structural and mechanical properties between operated and non-injured Achilles tendons in senior badminton players who had had Achilles tendon surgery and had returned to play.

METHODS

Eighteen players (age = 48.9(10.0)years), assigned to the unilateral Achilles tendon rupture group and 177 non-injured players (age = 55.4(9.4)years), assigned to the control group. A Logiq®S8 ultrasound was used to study tendon structure and elastography index values and a Myoton®PRO hand-held myotonometer was used to record the stiffness of the Achilles tendon.

FINDINGS

In Achilles tendon rupture group, operated tendons showed higher values than non-injured ones in thickness (Operated = 9.03(2.67)mm vs. non-injured = 5.88(0.88)mm; P < 0.001), width (Operated = 18.44(3.20)mm vs. non-injured = 16.80(1.97)mm; P = 0.039), cross sectional area (Operated = 140.33(60.29)mm² vs. non-injured = 74.40(17.09)mm²; P < 0.001) and elastography index (Operated = 2.05(1.35)A.U. vs. non-injured = 1.47(0.62)A.U.; P = 0.025). The bilateral differences shown by the Achilles tendon rupture group were greater than the bilateral differences shown by the control group for thickness (P < 0.001), width (P = 0.001), cross sectional area (P < 0.001), tone (P = 0.006) and dynamic stiffness (Achilles tendon rupture group = 10.85(23.90)N∙m^-1. vs. control group = 0.18(18.83)N∙m^-1; P = 0.031).

INTERPRETATION

Surgery on the Achilles tendon and adaptation to the mobilisation and strength training during rehabilitation could provoke structural and mechanical differences compared to the non-injured tendon. Furthermore, the differences between both Achilles tendons in the Achilles tendon rupture group was higher than the asymmetry observed between dominant and non-dominant Achilles tendons in the control group. In addition, the higher logarithmic decrement values showed by non-injured tendons in the Achilles tendon rupture group could be a tendinous injury risk factor.

Role of Ultrasound in Early Diagnosis of Stress Fracture: A Case Report of Bilateral Distal Fibular Stress Fracture in a Female Recreational Badminton Player

A 34-year-old female recreational badminton player presented with left ankle pain 1 week after a recreational badminton game. She reported experiencing a similar pattern of pain in her right ankle 4 months before that had persisted for 3 months. On plain radiography, callus formation was evident on the right distal fibula, and a subtle lesion was observed on the left side. Ultrasound was performed with the clinical suspicion of bilateral, nonsimultaneous, distal fibular stress fracture. Focal hyperechoic thickening of the periosteum with irregularity and hypoechoic periosteal edema over the left distal fibula were identified. These findings were consistent with stress fracture, and an early phase of distal fibular stress fracture was diagnosed. This case report highlights that ultrasound can be an alternative modality to magnetic resonance imaging or bone scan scintigraphy for the early diagnosis of stress fracture.