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THE POSSIBILITY OF CLASSIFYING V1 AND V2 SUB-TECHNIQUES OF A SINGLE IMU SENSOR THROUGH COMPARISON OF MOTION-SPECIFIC DATA(PITCH, YAW AND ROLL ANGLE VALUES-ORIENTATION ANGLE VALUE) IN XC SKI
Get PDFThe purpose of this study is to confirm whether the single IMU sensor module(LGE developing and providing for the experiments) that attached to the pelvis can distinguish the motion of the sub-techniques (V1, V2, V2A) with the accuracy of commercial XSENS(equipment consisting of 17 sensors) in freestyle(skate) xc skiing. Therefore, one elite male xc skier with eleven years experience was investigated by measuring the three-directional rotation angle for each of the three sub-techniques used in XC ski freestyle. Through this method, we could found not only the difference of motion patterns of each sub-techniques but also the possibility for replacement of multiple sensor system by a single IMU sensor module from LGE. Thus, it is expected that a single LGE IMU sensor module could be applied to repetitive and periodic sports such as XC ski
OPTIMAL REGRESSION MODEL FOR PREDICTING THE WINNING GAME AND CONTRIBUTING FACTORS IN ICE HOCKEY WORLD CHAMPIONSHIP
Get PDFThe purpose of this study was to present the statistical model to predict the winning of ice hockey game and determine the contributing factors for win in the world ice hockey championship. In order to find the optimal regression model for ice hockey, we compared two regression model (logistic and linear model) with the database of all games and the separate databases of top/bottom teams. The logistic regression model using the separate database was most accurately predicted the actual outcome of games. This model and database further revealed that goalkeeping and scoring efficiencies and the number of shots on goal were significantly contributing factors to win. In addition, the results for prediction analysis of winning rate for each team indicated that offensive skills were more important factors than defense power to increase winning rate for teams
FATIGUE INDUCED POSTURAL CHANGES IN AUSTRALIAN RULES FOOTBALL PLAYERS WITH AND WITHOUT A HISTORY OF HAMSTRING INJURY
Get PDFThe purpose of this study was to explore the influence of game fatigue on sprint mechanics in Australian Rules Football (ARF) players with and without a history of hamstring strain injury (HSI). Thirty community level ARF players, 11 with a HSI within the previous two years, undertook a game protocol simulating the running requirements of an ARF match. Three-dimensional kinematic trunk and lower limb data of 10 sprints were collected prior to the game protocol, and at the end of each simulated quarter, allowing the influence of game fatigue to be assessed. In players with a history of HSI, joint angle data revealed changes in sagittal plane hip and lumbar spine position with increasing fatigue. Persistent hamstring dysfunction may be revealed as the athlete progresses through a game and has potential implications for injury recurrence
TRUNK BIOMECHANICS DURING BREAKFALL FOR OSOTO-GARI AND ITS ASSOCIATION WITH JUDO-RELATED HEAD INJURY RISK IN NOVICE JUDOKAS
Get PDFThe incidence of head injuries in novice judo practitioners is of increasing public concern in Japan. This study investigated the correlation between trunk biomechanics and judo-related head injury risk in novice judokas with the aim of developing effective injury prevention strategies. Thirty-one novice judokas were volunteered to participate the study. Three-dimensional motion analysis of the osoto-gari breakfall was performed. A multiple regression analysis was usedto test the correlation between trunk biomechanics and possible head injury risk. We found a significant correlation between the trunk COM velocity and the peak neck angular momentum (F= 13.29, df= 3, P\u3c 0.001, r= 0.77). The result suggests that controlling the trunk COM angular velocity may play an important role in judo-related head injury prevention for novice judokas
LOWER LEG MORPHOLOGY AND STRETCH-SHORTENING CYCLE PERFORMANCE IN YOUNG AND ELDERLY MALES
Get PDFThe purpose of this investigation was to examine bone and muscle characteristics of the lower leg and stretch-shortening cycle capabilities of the ankle in young (22.3 ± 1.3 yrs) and elderly (67.5 ± 3.3 yrs) males. Peripheral quantitiative computed tomography (pQCT) was utilized to assess bone stress-strain index, bone ultimate fracture load, muscle density, muscle cross-sectional area (CSA), fat CSA and muscle+bone CSA. Maximal voluntary isometric plantarflexion (MVIP) force and force-velocity measurments during a countermovement hop (CMH) and drop hops from 20, 30 and 40 cm (DH20, DH30, DH40) were also measured. Bone stress-strain index was significantly higher in young males as well as muscle density, muscle CSA and muscle+bone CSA in comparison to elderly males. MVIP peak force and rate of force development was significantly higher in young males in comparsion to elderly males as well. An analysis of the force-velocity curves indicated that young males had significanlty higher levels of force and velocity in both the eccentric and concentric phase during the CMH, DH20, DH30 and DH40 in comparsion to elderly males. The data from this investigation indicate that aging potentially negatively influences lower leg bone and muscle strength and this may be reflected in lower stretch-shortening cycle capabilities of the ankle
WHOLE-BODY CONTROL STRATEGIES DURING ANTICIPATED AND UNANTICIPATED SIDESTEP MANOEUVRES PERFORMED BY FEMALES AND MALES
Get PDFThe purpose of this study was to investigate the influence of sex and planning time on spatial and temporal-level whole-body centre of mass (CoM) mechanics during the performance of the sidestep manoeuvre. Nine female and nine male collegiate team sport athletes completed seven anticipated and seven unanticipated sidestepping trials, during which three-dimensional CoM data were recorded. In addition to having a lower vertical CoM position during the preparatory phase (p \u3c 0.05), female athletes were found to have lower anterior-posterior velocity, but greater vertical velocity during the stance phase in comparison with their male counterparts (p \u3c 0.05). The findings provide evidence that female and male athletes utilise different whole-body dynamic control strategies to perform both anticipated and unanticipated sidestep manoeuvres
COORDINATION AND VARIABILITY IN AUSTRALIAN RULES FOOTBALL KICKING: IMPLICATIONS FOR PERFORMANCE
Get PDFThe purpose of this study was to quantify coordination and coordination variability (CV) of drop-punt kicking in professional Australian Football players and investigate the association between CV and in-game kicking performance and professional playing experience. Intra-limb couplings described to be associated with kicking accuracy were investigated during 30m successful drop-punt kicking efforts in 14 players. Coordination and CV were quantified using a modified vector coding technique. Higher CV of frontal plane trunk/pelvis, frontal and transverse plane thigh/leg and frontal plane leg/foot coupled motion were associated with higher in-game kicking performance. In-game kicking performance and CV did not change following two years of professional experience. These results highlight the significance of junior level skill development and kicking performance in talent identification
THE APPLICATION OF FOURIER ANALYSIS TO DEMONSTRATE THE IMPACT OF THE FLUTTER KICK ON LONGITUDINAL ROTATION IN FRONT CRAWL
Get PDFThe contribution of the flutter kick to front crawl performance from its influence on longitudinal body rotation has not been thoroughly investigated. Fourier analysis was used to examine the impact of the kick on segmental and whole body angular momentum about the body’s longitudinal axis in fourteen elite front crawl specialists swimming at sprint and 400m pace. The third harmonic frequency, representing the effects of the six-beat flutter kick, was greater at sprint than 400m pace in lower limb, upper limb, and whole body angular momentum. The presence of the third harmonic in upper limb and whole body angular momentum indicates that the flutter kick has an influence on longitudinal body rotation. The role of the flutter kick in front crawl performance may be linked to actions of the torso muscles to help control longitudinal body rotation
A PILOT INVESTIGATION INTO FORCE PRODUCTION IN TETHERED SWIMMING AS AN INDIVIDUAL MONITORING TOOL
Get PDFGaining an understanding of the physical capabilities and capacities that underpin the performance of a complex skill are important to help guide performance development at the elite level. The purpose of this study was to improve understanding of the force generating characteristics that relate to performance in elite swimmers. Three elite butterfly swimmers were tested over six weeks to examine the interactions between force-derived variables from 30 s of maximal tethered swimming and maximal 50m swimming performance, both performed using the butterfly stroke. Mean force, peak force and impulse per stroke all displayed very strong relationships with 50m swim time (r \u3e -0.8) and distance per stroke (r \u3e 0.8) in group analysis. Peak force and impulse per stroke were better than mean force at discriminating variations in performance for an individual
STEP-TO-STEP ANALYSIS OF ANTEROPOSTERIOR GROUND REACTION FORCE DURING 110 M HURDLE
Get PDFThe purpose of this study was to examine acceleration and deceleration profiles throughout the hurdle sprint until the 5th hurdle in terms of step-to-step ground reaction force. Four male collegiate hurdlers (performance range: 13.73–14.27 s) performed two maximal effort 60 m hurdle sprint. Ground reaction forces from the start to the 50 m mark was measured using 54 force platforms. The braking and propulsive impulse, the running speed and the amount of change of the speed at each step were calculated. The current results demonstrate that the force application profiles were different among four steps in one interval of a hurdle sprint, indicating that the role of each step in one interval is different. Moreover, the roles of steps in each interval likely does not change across the four intervals