Right-handed Players Research Articles

Comparison of dynamic balance indicators using the Star Excursion Balance Test method in men of various types of martial arts with left- and right-sided motor asymmetry

Purpose: to perform a comparison of the Star Excursion Balance Test indicators in men of various types of martial arts with left- and right-sided motor asymmetry. Material and methods. The results of the study were obtained at the Ivan Boberskyi Lviv State University of Physical Culture at the Department of Fencing, Boxing and National Martial Arts in the period October-December 2023. Qualified male martial artists aged 18-22 in the number of 84 participated in the collection of experimental material: 11 representatives WKF karate (including 1 left-hander), 12 members of fencing (including 2 left-handers), 9 representatives of hopak hand-to-hand combat (including 1 left-hander), 31 representatives of boxing (including 12 left-handers), 21 representatives of Kyokushinkai karate (among whom there was 1 left-handed person). Research methods: analysis of literary sources and materials from the Internet; survey (questionnaire); measurement of anthropometric indicators of athletes (height, body weight, length of arms and legs); measurement of Star Excursion Balance Test (SEBT); methods of mathematical statistics. Results: right-handed martial artists (n=67) had an anthropometric advantage over left-handed martial artists (n=17): height – 178.1 cm versus 177,5 cm, respectively, body weight – 70,9 kg versus 66,8 kg, length arms – 76,7 cm vs. 73,9 cm (P<0,05), leg length – 95,0 cm vs. 91,8 cm. Comparison of SEBT indicators revealed: left-handed group has better SEBT indicators in almost all positions, as on the left side of the body, as well as on the right. When comparing indicators of all 8 positions of SEBT of the left leg in right-handed and left-handed players, it was found that left-handed players had significantly (P<0,05) better indicators in positions 6 and 7. Left-handed martial artists demonstrated significantly (P<0,05) the best SEBT indicators in positions 6, 7, 8 of the right leg than right-handed martial artists. SEBT indicators of both right and left arms showed that positions 7, 8 of both left and right arms were significantly (P<0,05) better than those of right-handers. A separate phenomenal result is the specificity of passing the SEBT test by left-handed athletes: their results are significantly (P<0,05) better in the most difficult positions – 6, 7, 8, and in each of the four limbs of the body, regardless of motor asymmetry. Conclusions. The results of the work demonstrated phenomenal SEBT indicators in left-handed martial artists, compared to right-handed martial artists. This phenomenon is observed in all SEBT indicators of the lower and upper limbs of the left and right sides of the body: indicators of all SEBT positions in left-handed athletes are better than in right-handed athletes. Lefties reliably dominate in the most difficult positions of the test – 6, 7, 8, both in the girdle of the upper limbs and in the balance and flexibility of the lower limbs, regardless of asymmetry. This phenomenon is observed against the background of left-handed athletes lagging behind right-handed athletes according to anthropometric indicators. In view of the above, we assume that left-handed athletes have special properties of neuromuscular activity that require special in-depth research.

Performance of Elite Women's Singles Badminton Players: The Influence of Left-Handed Players.

The purpose of the study was to analyze the influence of left-handed athletes on the opponent (right-handed players) of elite badminton women's singles. The study selected a total of 40 women's singles matches played by elite female players: twenty matches (42 games, n = 42) were played between left-handed and right-handed players and twenty matches (44 games, n = 44) were played between two right-handed players. There were significant (p < 0.05) differences in hitting positions, techniques, routes and landing points. No significant (p > 0.05) differences were found in scores per game and frequency distribution of rally outcomes. In conclusion, the details of technical and tactical application were different in two game forms, the main impact of the left-handed player on the opponent's (right-handed player) game was a decrease in the opponent's stroke in the overhead, an increase in the number of drives, predominance of small slashes and a decrease in big slashes.

Kinematic differences between left- and right-handed cricket fast bowlers during the bowling action.

Despite differences between left- and right-handed athletes in other sports, minimal evidence exists regarding biomechanical similarities and differences between left- and right-handed cricket fast bowlers performing an equivalent task. This study aimed to compare the kinematics between left and right-handed fast bowlers performing an equivalent task (i.e. bowling 'over the wicket' to a batter of the same handedness as the bowler). Full body, three-dimensional kinematic data for six left-handed and 20 right-handed adolescent, male, fast bowlers were collected using the Xsens inertial measurement system. Time-normalised joint and segment angle time histories from back foot contact to follow-through ground contacts were compared between groups via statistical parametric mapping. Whole movement and subphase durations were also compared. Left-handed players displayed significantly more trunk flexion from 49%-56% of the total movement (ball release occurred at 54%; p = 0.037) and had shorter back foot contact durations on average (0.153 vs 0.177 s; p = 0.036) compared to right-handed players. Left- and right-handed bowlers displayed similar sagittal plane kinematics but appeared to use non-sagittal plane movements differently around the time of ball release. The kinematic differences identified in this study can inform future research investigating the effect of hand dominance on bowling performance and injury risk.

Notational Analysis of Wheelchair Paralympic Table Tennis Matches

Paralympic table tennis is the third largest paralympic sport for the number of players. Performance analysis was conducted for the rally duration and interval and impact of serve, whilst none investigated the shots distribution among classes of physical impairment. Therefore, the purpose of this study was to conduct a notational analysis of international competitions in relation to the wheelchair classes. Five matches for each wheelchair class (C1-to-C5) were evaluated from 20 elite male right-handed players. Both players for each match were analyzed for the following performance indicators: strokes type, the area of ball bouncing, and the shots outcome. Backhand shots were the most used technique for all classes. The most used strokes for C1 players were backhand and forehand drive and backhand lob, while for C5 players they were backhand and forehand push and backhand topspin. Similar shots distribution was registered for C2-to-C5 players. The central and far-from-the-net zone was mainly reached by the serve for all classes. Errors shots were similar in all classes, whilst winning shots were more frequent in C1. The current notational analysis provided a meaningful performance modelling of indicators for coaches and athletes that can be used to design training programs for each class.

Influence of functional asymmetry on performance of technical actions at freestyle wrestlers

Purpose: to reveal the influence of functional asymmetry on the performance of technical actions in freestyle wrestlers. Material and methods. Analysis of scientific and methodical literature and Internet sources; pedagogical testing; pedagogical experiment; methods of mathematical statistics. The profile of functional asymmetry of the brain in freestyle wrestlers was determined. We used the tapping test by E. Ilyin, tests to determine motor and visual asymmetry and dynamometry. According to the results of the tapping test, E. Ilyin, the coefficient of functional asymmetry was calculated based on the working capacity of the left and right hands. 24 freestyle wrestlers aged 18-21 took part in the study. Results: during the previous study it was found that wrestlers mainly perform technical actions in one direction. A sportsman at the initial stage of training must learn techniques in both directions. However, at the stage of maximum realization of individual capabilities this rule should not always be observed. Since the majority of respondents suggested that in order to improve sports results it is necessary to strengthen the asymmetry of the wrestler, a set of special exercises was applied in the experimental group. In the given complex the accentuated performance of basic technical actions in a convenient way, individual dosage of exercises on development of flexibility, force, and also static endurance on the leading side was provided. After conducting the pedagogical experiment, we again conducted educational and training matches and analyzed them according to the indicators that were interesting to us. Having processed the results obtained after conducting the pedagogical experiment, we reached the following conclusions. In the control group, the increase in results for all indicators was: «right-handed people to the right» - 4,4 %; «right-handed to the left» - 0,8 %; «left-handed to the right» - 3,9 %; «left-handed to the left» - 10,9 %. In the experimental group, according to the same indicators, we observed the following increase in results: «right-handed to the right» - 13,5 %; «right-handed to the left» - 0,4 %; «left-handed to the right» - 0,5 %; «left-handed to the left» - 18,7 %. The conducted statistical processing made it possible to establish that there was a reliable increase in technical actions in the convenient direction for both right-handed and left-handed players. Summarizing the results of the pedagogical experiment, we can come to the conclusion that the use of a set of exercises embedded in the accented execution of technical processes in the leading direction contributes to the increase in results and the increase in the efficiency of the execution of technical processes. Conclusions. The analysis of the distribution of the individual profile of functional asymmetry in freestyle wrestlers showed that among the 24 wrestlers we studied aged 18-21 years, the right-sided profile of functional asymmetry predominates – 66 % of wrestlers, the left-sided profile of functional asymmetry has 20 % of wrestlers, the rest 14 % are ambidexters. The presence of a connection between the performance of a technical action and the profile of functional asymmetry in wrestlers was revealed: athletes perform technical actions in the leading direction more often and more efficiently. The use of a complex of exercises aimed at increasing asymmetry contributes to the growth of technical processes, and more pronounced in the leading direction. Thus, the increase in the control group «right-handed to the right» was 4,4 %, «left-handed to the left» - 10,9 %, in the experimental group – 13,5 % and 18,7 %, respectively.

The relative age effect in top 100 elite female tennis players in 2007-2016.

The Relative Age Effect (RAE) has been the subject of many studies, but few have focused on professional athletes in individual sports. The aim of this study was to verify the existence of the RAE among elite senior female tennis players (top 100 players) in the WTA Rankings (n = 1000) in the years 2007-2016. The analysis was performed among top 100, resp. top 10 female tennis players, among players in 4 age subgroups and among left-handed (LH) and right-handed (RH) players. The existence of the RAE was assessed with the use of chi-square test (goodness of fit). More than half of top 100 players were born in first semester: both in individual years (53.0-63.0%) and in the whole observed period (58.4%). Significant RAE (ES medium) was observed in top 100 female players only in 2012 and 2016; significant RAE (ES small) was detected in the period of 2007-2016. Among the top 10 players, significant RAE (ES medium) was demonstrated during the whole period. No significant RAE (ES medium) was detected in the 17-18y subgroups, significant in 19-24y and 25-30y (ES small) as well as in 31-36y (ES medium). Although significant RAE was observed in the subgroups of LH and RH female players, ES was large only in the LH. The results contribute to the expansion of the knowledge about the reduction of the RAE existence in adulthood among coaches, athletes and tennis officials.

Cross-infection risks of SARS-CoV-2 while playing catch using a baseball: Creating a safe sporting environment during the COVID-19 pandemic.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease (COVID-19), is found primarily in the respiratory tract secretions of infected individuals with one of the main routes of transmission being direct or indirect contact. In this study, using fluorescent paint, we evaluated the spread of contaminants while playing catch with a baseball. Fluorescent paint was applied to the right hand of a right-handed baseball player who then engaged in playing catch with 10 other right-handed players (partners) for 5 min each. The fluorescent paint was detected on the right hands (inside) and gloves (inside) of all the 10 partners as well as on the ball; in some partners it was also detected on the back of the right hands or the back of the gloves. However, except for their right hands, fluorescent paint was not detected on the surface of the bodies of the partners. These observations indicated that the fluorescent paint (mimicking virus-containing contaminants) on the hand spreads very efficiently from person to person during the throwing and catching of a baseball, suggesting that a thorough and frequent disinfection of the hands and equipment is important in the prevention of infections that may occur while playing baseball.

Grip position affects upper limb kinematic chain during tennis double-handed backhand topspin strokes: considerations for transitioning tennis grip position technique

ABSTRACT The purpose of this study was to compare the upper limb kinematic chain of tennis players using either an eastern or continental non-dominant grip position during the forward swing of the double-handed backhand stroke. Sixteen right-handed tennis players performed backhands using two non-dominant grip positions (eastern and continental), aiming for two cross-court zones (deep and short). Trajectory data were captured using sixty reflective markers attached to the upper limb and racket using a 12-camera Vicon motion capture system (250 Hz). Peak angular velocity was significantly greater for multiple joint rotations at the dominant shoulder and entire non-dominant limb in the eastern grip. Subsequently, greater peak racket head angular velocity and post-impact ball speed were generated by the eastern grip, while shot accuracy was similar between grip types. There was delayed dominant shoulder peak adduction angular velocity for the continental grip, possibly due to a lack of skill familiarity causing changes in coordinative patterns. Collectively, the non-dominant grip position appears to influence proximal and distal upper limb movement. Future research should explore upper limb segment coordination comparing preferred and non-preferred double-handed backhand techniques and complete inter-disciplinary investigations to understand what grip positions are most effective for individuals to learn double-handed backhands.

The Effect of Coordinative Locomotor Training Using Elastic Bands on the Flexibility and Body Alignment of Elementary School Right-Handed Baseball Players

The Effect of Coordinative Locomotor Training Using Elastic Bands on the Flexibility and Body Alignment of Elementary School Right-Handed Baseball Players

Unilateral versus Bilateral Landing after Spike Jumps in Male and Female Volleyball: A Systematic Review

Background: The spike is a key action in volleyball, and the landing technique and its asymmetries are commonly associated with an increased risk of injury. Objectives: The aim of this systematic review was to assess how male and female volleyball players land (i.e., unilaterally, or bilaterally) after spike jumps in matches and analytical settings (field or laboratory). Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines were followed, with eligibility criteria defined according to participants, interventions, comparators, study design (PICOS): (p) healthy indoor volleyball players of any sex, age group, or competitive level; (i) exposure to landing after spike actions during official matches AND/OR simulated 6 vs. 6 games AND/OR analytical training conditions AND/OR laboratorial experiments; (c) not mandatory; (o) data on landing mechanics after spike actions, including reporting of whether the landing was unilateral or bilateral; (s) no restrictions imposed on study design. Searches were performed in seven electronic databases (Cochrane Library, EBSCO, PubMed, Scielo, Scopus, SPORTDiscus, and Web of Science) on 23 April 2021. Results: Automated searches provided 420 results. Removal of 119 duplicates resulted in 301 records being screened for titles and abstracts. A total of 25 studies were eligible for full-text analysis. Of these, eight studies were deemed eligible for inclusion in the review. Studies showed that (i) attackers landed asymmetrically 68% of the times (61% left leg, 7% right leg); (ii) bilateral asymmetries were observed for the hip, knee, and ankle joints; (iii) bilateral asymmetries were observed even when players were instructed to land evenly on two feet; (iv) landing contact of the leg opposite to the hitting arm preceded the contact of the homolateral leg. One match analysis study showed that men landed more often on the left (31.5%) or right foot (8.5%) than women (23.7% and 1.6%). Conclusions: Studies analyzing spike landing showed a prevalence of unilateral landings (mostly the left leg first, for right-handed players) in men and women but more prevalently in men. Registration INPLASY202140104, DOI: 10.37766/inplasy2021.4.0104.

Kinaesthetic cues when predicting the outcomes of the actions of others.

People can accurately predict others' action outcomes. To do so, recent studies have proposed that skilled athletes rely preferentially on sensorimotor resonance mechanisms that simulate-in their own motor system-the actions of others. However, little is known about which types of information are simulated for prediction. Here, we used a movement-illusion that selectively affected kinaesthetic sensation to investigate whether athletes use kinaesthetic information for simulation when predicting action outcomes. Nine skilled and 9 less-skilled right-handed basketball players predicted the outcomes of basketball shots when viewing an occluded video of another right-handed player's shots in each of 3 conditions: (a) observation alone (control), (b) observation + vibration-induced illusory kinaesthetic sensation in the right-wrist (effector vibration), and (c) observation + vibration in the left-wrist (noneffector vibration). Results revealed that the enhanced prediction of skilled players in the control condition was eliminated in the effector vibration condition but not in the noneffector condition. Additionally, when participants made correct predictions, their subjective feeling of wrist-flexion induced by vibration became larger when participants observed the longer shot in the effector condition but not the noneffector condition. The results suggest that skilled players use limb-specific kinaesthetic information, when it is available, as a means of predicting the action outcomes of others. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Relative Age Effects as Evidence of Selection Bias in Major League Baseball Draftees (2013-2018).

Herring, CH, Beyer, KS, and Fukuda, DH. Relative age effects as evidence of selection bias in major league baseball draftees (2013-2018). J Strength Cond Res 35(3): 644-651, 2021-The purpose of this study was to examine if relative age effects (RAEs) or the unequal birth-date distribution among a cohort group of individuals exist in Major League Baseball (MLB) draftees. This study comprised 7,078 men drafted in the MLB first-year player draft from 2013 to 2018. Data collected for each draftee included birth date, year drafted, academic-level classification, position, round drafted, batting side, and throwing arm. Draftee's birth dates were categorized into quarters based on the calendar year for baseball in the United States (Q1: August-October; Q2: November-January; Q3: February-April; Q4: May-July). Player birth-date distributions were compared with average expected birth-date distributions and evaluated with the χ2 goodness of fit statistic. Significant χ2 tests were followed up by calculating the standardized residual for each quarter. Differences from the expected frequencies were found for the overall group (p < 0.001) with standardized residuals for baseball athletes born in Q1 (z = +4.45) and Q3 (z = -4.15) exceeding ±2.0. Similar patterns were noted for high schoolers (Q1: z = +3.30; Q3: z = -3.28), pitchers (Q1: z = +2.78; Q3: z = -3.12), early middle rounders (Q1: z = +3.08; Q3: z = -2.67), late rounders (Q1: z = +2.70; Q3: z = -2.61), right-side hitters (Q1: z = +3.23; Q3: z = -2.26), left-handed pitchers (Q1: z = + 2.12; Q3: z = -2.59), and right-handed positional players (Q1: z = +3.12; Q3: z = -2.12). Consistent with the majority of previous research, RAEs are apparent in MLB draftees, with specific patterns of unequal distribution among subsets of athletes.

Can the Open Stance Forehand Increase the Risk of Hip Injuries in Tennis Players?

Background:The open stance forehand has been hypothesized by tennis experts (coaches, scientists, and clinicians) to be more traumatic than the neutral stance forehand as regards hip injuries in tennis. However, the influence of the forehand stance (open or neutral) on hip kinematics and loading has not been assessed.Purpose:To compare the kinematics and kinetics at the hip joint during 3 common forehand stances (attacking neutral stance [ANS], attacking open stance [AOS], defensive open stance [DOS]) in advanced tennis players to determine whether the open stance forehand induces higher hip loading.Study Design:Descriptive laboratory study.Methods:The ANS, AOS, and DOS forehand strokes of 8 advanced right-handed tennis players were recorded with an optoelectronic motion capture system. The flexion-extension, abduction-adduction, and external-internal rotation angles as well as intersegmental forces and torques of the right hip were calculated using inverse dynamics.Results:The DOS demonstrated significantly higher values than both the ANS and AOS for anterior (P < .001), medial (P < .001), and distractive (P < .001) forces as well as extension (P = .004), abduction (P < .001), and external rotation (P < .001) torques. The AOS showed higher distractive forces than the ANS (P = .048). The DOS showed more extreme angles of hip flexion (P < .001), abduction (P < .001), and external rotation (P = .010).Conclusion:The findings of this study imply that the DOS increased hip joint angles and loading, thus potentially increasing the risk of hip overuse injuries. The DOS-induced hip motion could put players at a higher risk of posterior-superior hip impingement compared with the ANS and AOS.Clinical Relevance:Coaches and clinicians with players who have experienced hip pain or sustained injuries should encourage them to use a more neutral stance and develop a more aggressive playing style to avoid the DOS, during which hip motion and loading are more extreme.

Motor competence is not enough: Handedness does not facilitate visual anticipation of same-handed action outcome

Visual understanding of others performing an action depends on both an observer's visual and motor experience with that action. With regard to visual anticipation of lateralized action outcome in one-on-one confrontative situations, however, the particular role of motor experience is poorly understood. Here, we considered handedness to test the laterality-specific contribution of visual and motor experience to action outcome anticipation. In two experiments, 55 left- and 114 right-handed handball players predicted the outcome (Exp. 1: throw direction; Exp. 2: type of throw) of videos showing left- and right-handed penalty-throws viewed from a goalkeeper's perspective. Analyses reveal that left- and right-handed participants performed similarly and had more difficulties anticipating the outcome direction, but not type of throw, of left- compared to right-handed penalties. Thus, albeit left- and right-handers differ in their lateralized motor experience, this does not seem to be sufficient to facilitate visual anticipation of same-handed action outcome. Instead, findings lend further support to the specificity of perceptual learning and visual experience arising from both left- and right-handers' predominant exposure to more common right-handed movements.

A kinematic analysis of the upper limb during the topspin double-handed backhand stroke in tennis

ABSTRACT The purpose of this study was to compare double-handed backhand kinematics of the non-dominant wrist of tennis players using either an eastern or continental grip position with the non-dominant hand. Trajectory data were captured using sixty reflective markers on sixteen sub-elite right-handed tennis players using a 12-camera VICON motion capture system (250 Hz). Participants executed double-handed backhands using two non-dominant grip positions (Eastern [E] and Continental [C]), aiming for two crosscourt zones (Deep [D] and Short [S]), totalling to four conditions (ED, CD, ES and CS). Three successful attempts from each condition were selected for analysis. The eastern grip demonstrated faster horizontal racket head velocity compared to the continental grip. However, no differences were observed in accuracy or spin rate between grips (p > 0.05). In the non-dominant upper limb, elbow flexion was smaller in the continental condition throughout the swing, whilst wrist extension and ulnar deviation was larger. Collectively, these data suggest that the continental grip may place the wrist in a position vulnerable to overuse injury. Future research into the kinetics of the double-handed backhand would help better understand the onset of ulnar-side wrist pain in tennis.

Baseball Players' Eye Movements and Higher Coincident-Timing Task Performance.

Previous studies have reported that baseball players have higher than average visual information processing abilities and outstanding motor control. The speed and position of the baseball and the batter are constantly changing, leading skilled players to acquire highly accurate visual information processing and decision-making. This study sought to clarify how movement of the eyes is associated with baseball players’ higher coincident-timing task performance. We recruited 15 right-handed baseball players and 15 age-matched track and field athletes. On a computer-based coincident-timing task, we instructed participants to stop a computer image of a moving target by pressing a button at a designated point. We presented bidirectional moving targets with various velocities, presented in a random order. The targets’ moving angular velocity varied between 100, 83, 71, 63, 56, 50, and 46 deg/s. We conducted 168 repetitions (42 reps × 4 sets) of this coincident-timing task and measured participants’ eye movements during the task using Pupil Centre Corneal Reflection. Mixed-design analysis of variance results revealed participant group effects in favor of baseball players for timing absolute error and low absolute error, as predicted from prior visual processing and decision-making research with baseball players. However, in contrast to prior research, we found significantly shorter smooth-pursuit onset latency in elite baseball players, and there were no significant group differences for saccade onset and offset latencies. This may be explained by the difference in our research paradigm with mobile targets randomly presented at various velocities from the left and right. Our data showed baseball players’ higher than normal simultaneous timing execution for making decisions and movements based on visual information, even under laboratory conditions with randomly moving mobile targets.

Do left-handed players have a strategic advantage in table tennis?

The reasons for the overrepresentation of left-handed players (LHps) in some sports are widely discussed in the literature. In light of this debate, this study aimed to assess the associations between players’ handedness and selected performance indicators in table tennis, where LHps represent 25% of top-level players. A notational analysis was conducted on 20 men’s matches including any combination of players’ handedness. Participants were in the first 150 positions of the ITTF world ranking at the moment the matches were played. The table area of ball bouncing after serving, and the shot type used by the receiving and subsequently the serving player, were recorded for 1515 rallies. Each half of the table was divided into six equal rectangular areas. There was a significant effect of players’ handedness on percentage of ball bouncing in different areas. Specifically, LHps showed a greater capacity (or choice) to adjust the serve (in terms of areas of ball bouncing) than right-handed players (RHps) according to the opponent’s handedness. Furthermore, LHps used offensive shots more frequently. In conclusion, both play strategy and characteristics such as higher offensiveness, together may contribute to the success of LHps in table tennis. These findings emphasise the need for a multifactorial approach in future research aiming to understand why LHps may be advantaged in different sports.

Lateral differences in maximal grip strength in Czech male tennis players aged 11 – 12 in the context of injury prevention

The term laterality indicates the one-sided preference or functional advantage of the stronger, more accurate and coordinated limbs or organs and the brain hemisphere of a human body. In the preference process, more accurate, precise, coordinated and stronger side is chosen from the perspective of motoric functions. Among the general population is about 10-13% of left-handers and in certain sport fields this percentage may (baseball, tennis, box etc.). The left-handed dominance in tennis is considered an advantage. Due to unilateral load, there may be an excessive side-effect in strength differences in tennis and overloading of specific muscle group could lead to an injury. The aim of the research was to identify the levels of somatic and strength characteristics and assess the lateral difference in maximal grip strength of Czech elite male tennis players. The sample consisted of male tennis players, ranging in age from 11 to 12.9 years (n=186) who participated in the regular tests for Czech Tennis Association in years 2000-2018. Base anthropometrics were measured (height, weight) and maximal grip strength of both hands using the hand-held dynamometry (Grip D, Takei). Data came from normal distribution (statistically proven – chi-square test). The basic statistical characteristics were calculated (body height, M=155.08±7.98 cm; body weight, M=43.45±7.13 kg; strength of right hand: M=24.88±4.67 kp; strength of left hand: M=21.70±4.74 kp). It was found that 87.6% of the players (n=163) were right-handed and the remaining 12.4% left-handed (n=23). The assessment of the significance (Cohen´s d) between the dominant (playing) hand for the right-handed and left-handed players showed small effect size (dominant hand right: MRHR=25.11±4.41 kp, dominant hand left: MLHL=26.62±5.65 kp; d=0.30, small) in favor of the left-handed players. The difference between the dominant and the non-dominant hand showed large effect size for the right-handed (dominant hand right vs. hand left; MRHR=25.11±4.41 kp, MRHL=21.01±4.15 kp, d=0.96, large) and medium effect size for the left-handed players (dominant hand left vs. hand right; MLHL=26.62±5.65 kp, MLHR=23.24±5.98 kp, d=0.58, medium). The results showed that the value of 15 % level of strength laterality between dominant and non-dominant hand was exceeded for the right-handed (55.83 %) and left-handed (43.48%) groups ergo the exceeded value could be a cause of injuries. Because of this signals attention should be given during training process for optimizing the required load.

Kinect-Based Badminton Motion Analysis Using Intelligent Adaptive Range of Movement Index

Badminton is a type of racquet sport that is played using racquets to strike a shuttlecock within a netted rectangular court, and it is one of the most popular sport in Malaysia. In this paper, the team expanded their previous adaptive novel lossless compact view invariant compression technique, named adaptive range of movement index (RoMI) by embedding an intelligent mapping algorithm. Badminton players are broadly classified into two handedness groups, which are left-handed players and right-handed players. The adaptive RoMI technique in the previous module is capable of identifying the labels of normalized RoMI and perform adaptive mapping for badminton players of different handedness. However, the mechanism requires manual judgement from humans to select the type of handedness. This technique will increase the error rate and effort of importing data properties with incorrect manual handedness input or data stream from different handedness datasets of badminton players. Thus, the proposed intelligent adaptive RoMI technique enables the analyzing system to outperform the previous module by detecting the labels of normalized RoMI automatically and by performing intelligent mapping. The motion analysis system will then become much more efficient, intelligent hence simplifying data collection and the handedness invariant benchmarking approach.

An exploration of the effect of proprioceptive knee bracing on biomechanics during a badminton lunge to the net, and the implications to injury mechanisms.

The aim of this study was to determine changes in knee biomechanics during badminton lunges due to fatigue, lunge strategy and knee bracing. Kinetic and kinematic data were collected from 16 experienced right-handed badminton players. Three factor repeated measures ANOVAs (lunge direction—fatigue—brace) were performed with Least Significant Difference pairwise comparisons. In addition, clinical assessments including; Y-balance test, one leg hop distance and ankle dorsiflexion range of motion were performed pre- and postfatigue. The knee showed significantly greater flexion during the forehand lunge compared to backhand. In contrast, the internal rotation velocity and the knee extension moment were greater during backhand. Knee angular velocity in the sagittal plane, peak knee moment and range of moment in the coronal plane and stance time showed significantly lower values postfatigue. In addition, the peak knee adduction moment showed significantly lower values in the braced condition in both the fatigued and nonfatigues states, and no significant differences were seen for peak vertical force, loading rate, approach velocity, or in any of the clinical assessment scores. There appears to be greater risk factors when performing a backhand lunge to the net compared to a forehand lunge, and proprioceptive bracing appears to reduce the loading at the knee.