ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
Not a member yet
5464 research outputs found
Sort by
CAUSALITY IN THE FEEDBACK LOOP DURiNG BALANCING TASKS: INTERMITTENT CONTROL OF QUIET STANDING
Get PDFThe aim of this study was to investigate the relationship between the timing of intermittent muscle activity and joint fluctuation and between intermittent muscle activity and joint torque output. Eight healthy male participants stood quietly on the force platform for 120 sec, while we measured angular displacements and joint toque of the ankle, knee, and hip in the sagittal plane. Surface electromyography from six leg muscles of each leg was also recorded to determine phasic muscle activation and deactivation for each muscle by using two low-pass filters. We found that muscle activation and deactivation periods were in accordance with joint position and velocity and were associated with torque fluctuations in the anatomical action direction. These results succeeded in experimentally visualizing the causality of the feedback loop of the postural control mechanism
THE EFFECTS OF EXERCISE ON COGNITIVE FUNCTION, AND BALANCE IN HEALTHY INDIVIDUALS - A PILOT STUDY
Get PDFConcussion is defined as an injury to the brain caused by forces applied to the head. Approximately 10-20% of concussed individuals develop post-concussion syndrome (PCS), characterized by persistent symptoms beyond 10 days including balance and cognitive deficits. The purpose of this pilot study was to explore the effect of a four-week exercise program on physiological, cognitive, and balance variables in a sample of healthy, physically active individuals to gather preliminary information to apply to a future PCS population. Statistically significant changes in reaction time and balance measures were observed. No changes in heart rate, blood pressure, memory, or visual motor speed were observed. Balance improvements in this healthy sample suggest that future exploration of a similar exercise program in those experiencing PCS may provide valuable information
SAGITTAL HIP - KNEE COORDINATION DURING A 45 DEGREE CUTTING TASK
Get PDFConcurrent extension at the hip and flexion at the knee has been suggested as a high risk coordination pattern for the anterior cruciate ligament (ACL). Nine elite female athletes performed ten 45" cutting tasks before and alter a multi-directional fatiguing protocol. Force and kinematic data were captured. Vector coding was used to calculate sagittal hip - knee coordination for the first 40 ms of foot contact of the dominant limb and percentage time spent in each coordination pattern was extracted. Hip extension - knee flexion was the dominant coordination pattern pre- and post-fatigue ( P less than 0.05)t the time spent in this coordination pattern did not change as a result of fatigue. The hypothesised high risk hip extension - knee flexion was the dominant coordination pattern during the 45\u27 cutting task
FATIGUE-RELATED ASYMMETRY AND INSTABILITY DURING A 3200-M TIME-TRIAL PERFORMANCE IN HEALTHY RUNNERS
Get PDFThe purpose of this study was to examine fatigue effects on symmetry and stability during a maximal effort running time-trial m). Recreational runners had continuous recordings of 3D trunk acceleration parameters (spatio-temporal, RMS vector ratio, step symmetry, and stride regularity) during the lT. Statistical analysis was carried out using generalised estimating equations (GEE) to investigate longitudinal changes (laps two to eight) compared to baseline (lap one), while statistically adjusting for running speed. Runners had significantly longer contact times (4m lap onwards), higher mediolateral root mean square (RMS) ratio (3d lap onwards), lower vertical symmetry and vertical RMS ratio (final lap). Coaches could use these results to recognize, minimize, and delay fatigue related onset of asymmetries and instabilities possibly through training strategies
LEADING EDGE OF CYBERNICS: INNOVATIVE CYBORG-TYPE ROBOT "HAL" TO IMPROVE, SUPPORT, AND EXPAND HUMAN\u27S ABILITY
Get PDF\u27Cybernics: the fusion and combination of humans, robots and information systems" is a new interdisciplinary academic field centering on cybernetics, mechatronics and informatics in which neuroscience, robotics, information technology, physiology, psychology, laws, ethics, and business administration are deeply intertwined. HAL (Hybrid Assistive Limb) is the world\u27s first cyborg-type robot. HAL, developed through Cybernic technologies, detects faint bio-electrical signals transmitted from the wearer\u27s brain through the nervous systems to the muscles, and assists the user\u27s intended movement. This technology is sensing accurately potential signals while moving human body, making HAL move a little earlier than human muscle contractions. HAL (Hybrid Assistive Limb) was realized by it to improve, support, and expand human\u27s ability
NEW METHODS FOR MOBILITY PERFORMANCE MEASUREMENT IN WHEELCHAIR BASKETBALL
Get PDFIncreased professionalism in wheelchair sports demand a more precise and quantitative measure of individual wheelchair mobility performance, to allow it to be an evaluation measure of wheelchair setting or training optimization. This research describes the application of an inertial sensor based method for measuring wheelchair kinematics and a factor analysis based selection of outcomes best describing wheelchair mobility performance. This set of kinematic outcomes was analysed for sensitivity towards wheelchair performance differences due to competition level and classification of the match data of 29 wheelchair basketball athletes. The method proved sensitive and is believed to provide a solid basis for a kinematics based definition of wheelchair mobility performance in sports
TEST-RETEST RELIABILITY OF PAIRED PREFERENCE TEST FOR THE WEIGHTED SHOES
Get PDFThe purpose of this study was to examine the test-retest reliability of paired preference test for the weighted shoes. Forty participants were recruited and instructed to put on the weighted shoes and choose the preferred one after completing four paired comparisons. During the tests, participants were blind of any information from the shoes. All the participants were invited to repeat the same procedure one week after the first session. The results in first session showed that thirty-two (80%) out of the forty participants preferred Shoe D or E, which centre of mass was close to the rear end of the shoe. The greater intra-class correlation coefficient (ICC=0.81) represents the perfect test-retest reliability of the paired preference test. The test protocol designed in this study could apparently reduce the numbers of the paired comparison under the characteristic of the testing shoe varied systematically, for example the weighted shoes used in this study
THE DETERMINATION OF BREAK POINTS IN TIME SERIES DATA
No full textThe aim of this paper was to demonstrate three possible methods for the quantification of breakpoints. Data were the elbow angle during the pull phase of 10 strokes of ergometer rowing. First, a piecewise linear regression of two segments separated by a breakpoint was applied iteratively whereby the minimum pooled squared error of both regressions was the breakpoint. Second, the last local maxima, identified through zero-crossings of the first derivative, was the breakpoint. Thirdly, the last time point at which the rate of change of the joint angle data crossed a threshold was identified as the breakpoint. Each of these methods was checked against visual determination of the breakpoints. The threshold method was closer to the breakpoint as identified by visual inspection than were the linear regression and local maxima methods, and appeared suitable for this application
THE IMPACT PHASE OF DROP PUNT KICKING: VALIDATION AND EXPERIMENTAL DATA OF A MECHANICAL KICKING LIMB
Get PDFThe purpose of this study was to validate a mechanical kicking limb and analyse changes in foot speed on impact characteristics of drop punt kicking. Foot speed was recorded as 9.1 - 21.2 mls, and covered a range of kick distances. Ball speed (13.0 - 29.7 m/s), contact distance (10.7 - 20.2 cm) and contact time (14.75 - 11.75 ms) were comparable to drop punt kicking. lmpact efficiency (F:B ratio = 1.37 - I .48, coefficient of restitution = 0.66 - 0.79) were high, caused by near perfect rigidity in the design of the limb. Overall, the limb was found to be a valid representation of a human performer. Foot speed displayed significant relationships with ball speed (r = 0.998), contact time (r = -0.89), contact distance (r = 0.99) and F:B ratio (r = -0.694). The relationship between foot speed and COR (-0.347) was not significant
MEASUREMENT OF STRIKING IMPACT KLNETKS VIA INERTIAL MODELLING AND ACCELEROMETRY
Get PDFStriking impact has teen explored repeatedly in combat sports. The majority of methods used in the literature require intricate equipment. This study implemented a novel and simple method of measuring impact kinetics using a common, commercially available striking bag. Impulse and peak force of impacts were determined, with reliability and validity statistics obtained from multiple impacts with a custom ballistic pendulum. Test-retest reliability calculations determined that all measures had acceptable reliability (CVI less than/ equal to 2.4%). Using linear regression modelling, the coefficient of determination scores displayed a good fit for the model (R exponent 2 greater than / equal to 0.96) when plotted with a spectrum of pendulum masses. This novel method represents a reliable and valid approach to measuring striking impact kinetics which is easily adaptable to any type of hanging striking target