ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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EXAMINATION OF A METHOD FOR DETECTION OF WALKING HEEL STRIKE AND TOE-OFF OVER A WIDE RANGE OF SPEEDS
Get PDFThis study examines a simple method to accurately detect heel strike (HS) and toe off (TO) timing over a wide range of walking speeds. HS was the moment when the heel passed a threshold in the downward direction. TO was the moment when the fifth metatarsal passed the threshold in the upward direction. The accuracies of these measurements were evaluated by comparing the moment acquired using a force platform. The root mean square (RMS) errors were 6.10 ms for HS and 15.6 ms for TO. These errors were smaller than those of previous studies. Furthermore, walking speed did not affect the detection precision in this method. Therefore, the detection method proposed in this study can detect HS and TO timing with better accuracy over a wide range of walking speed than previous methods
MODELLING NON-PLANAR PELVIS AND TRUNK ROTATIONS IN A PLANAR SIMULATION MODEL
No full textIn whole body planar simulation models the bilateral hip and shoulder joint centres are assumed to be symmetrical. Non-planar rotations of the pelvis and trunk can cause these joint centres to be asymmetrical. In order to allow asymmetrical hip and shoulder joint centres in a planar simulation model a massless segment method was used in an angle driven simulation model of the front foot contact phase of fast bowling. The model was customised to an elite fast bowler by closely matching three performances and evaluated. It was concluded that the massless segments method to allow asymmetrical hip and shoulder joint centres within a planar simulation model was suitable to reproduce predominately planar movements
OPTIMAL PROSTHESES, ORTHOSES AND EXOSKELETONS FOR PHYSICAL ACTIVITY
Get PDFWearable physical assistive devices, such as prostheses, orthoses and exoskeletons are great inventions to enable a large range of subjects with very different disabilities, injuries or diseases to perform physical activity who would not be able to do so otherwise. The purpose of this paper is to present the benefits of model-based optimization methods to analyze and improve these devices such that they are best adapted to address the need of different pathologies or even individual subjects. Using detailed multibody system models of the human and the wearable devices, it is possible to tune parameters related to the kinematics, dynamics and control of the devices or even test completely new design ideas or setups. Optimization problems are formulated and solved in order to fit simulated motions of the combined system of human and wearable device to desired behaviour e.g. coming from motion recordings of healthy subjects or to generate motions that optimize particular performance criteria. The presented approach also allows to study the frequently asked question if certain prosthetic devices create and advantage of the wearer over able-bodies subjects
PHYSICAL ACTIVITY IN VIRTUAL REALITY
Get PDFThe purpose of this conference is to discuss about research on human physical activity based on Virtual Reality (VR). VR 1) offers a unique compromise between control and ecological property of the studied situation, 2) enables to enrich/modify the physical environment, 3) provides control on the multisensory feedback given to the user, 4) and has the potential to enhance motivation and increase the number of repetition in motor skills training. Recent democratisation of immersive technologies, with the development of cheap interactive devices for videogames, has encouraged research in this domain. In this conference, we will address examples of perception-action coupling analysis based on VR, will analyse how technical choices could affect the behaviour of the studied subjects, and will expose perspectives in motor skills training based on VR
PROPHYLACTIC EVALUATION OF SHOULDER PROPRIOCEPTION IN ELITE SWIMMERS
Get PDFIt is suggested that poor shoulder proprioception contributes to shoulder pain in swimmers. However, there is a lack of studies describing the measurement method for shoulder proprioception. The purposes of this preliminary study was to investigate the scapular position depending on arm scaption as a first step in the development of a measurement method for three-dimensional shoulder proprioception. An asymptomatic young adults participated in this study. His scapular rotation were measured as a function of arm position during scaption in two consecutive days. The results showed that scapular rotations are not a reproducible function of humerus elevation. Those findings suggested that the assessement of shoulder proprioception should rely on the evaluation of both gleno-humeral and scapulo-thoracic joints to be valid
VALIDITY OF A MAKER-BASED LOCATOR FOR MEASURING IN VIVO THREEDIMENSIONAL SCAPULAR STATIC POSES USING STEREOPHOTOGRAMMETRY
Get PDFThe study aimed to (1) develop a marker-based scapular locator for measuring scapular poses and (2) to design an in vivo experimental procedure for this static marker-based measurement method to decrease measurement errors, and (3) to validate this scapular locator and the experimental procedure. Six young male adults were implanted into the spine of the scapula with two bone-pins that were attached with a cluster of four retroreflective markers (bone markers). The scapular poses were measured simultaneously using the developed scapular locator and the bone markers. The results showed that very high validity for scapular rotations and for the acromial angle (AA), the root of spine (RS) and the inferior angle (IA) of the scapular translation were achieved. Two main reasons contributed to the results: (1) the adjustable scapular locator and (2) careful palpation of the bony landmarks over the scapula
THE EFFECT OF FATIGUE ON LOWER LIMB MOTOR VARIABILITY DURING A CONTROLLED REPETITIVE STRETCH-SHORTEN CYCLE TASK
Get PDFThis study evaluated changes in lower limb joint coupling variability during single-leg hopping to exhaustion. Twenty recreationally active male and female participants performed single-leg hopping at 2.2 Hz to a target height. At 0, 20, 40, 60, 80 and 100% of the total duration of hopping, spatio-temporal characteristics and variability of the kneeankle (KA) and hip-knee (HK) joint couplings were determined. There was a significant increase in variability of the KA and HK joint couplings in the flexion-extension axes during the loading and propulsion phases as hopping progressed. However, there was maintenance of performance output characteristics throughout the task. These findings suggest that changes in joint coupling variability may be a compensatory strategy to allow continuous single-leg hopping as the effects of muscular fatigue increase
LOWER LIMB COORDINATION DURING A LAND-CUT TASK FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION AND REHABILITATION
Get PDFThis study compared the lower limb coordination of the previously injured leg of ACL injured participantsparticipants (ACLr, n=18), against their non-injured leg and a control (nACL, n=18) leg. The lower limb joint and segment couplings were calculated during maximal drop-jump land and unanticipated cutting task. Differences between the previously injured and nACL control leg were present in all but one of the lower limb joint and segment couplings. Differences between the previously injured and nACL control leg were present in the hip rotation - knee abduction adduction, and knee rotation knee abduction adduction couplings. The hip and thigh were the main areas where differences were reported. Altered proximal neuromuscular function may be the origin of these altered coordination patterns
LANDING TECHNIQUE IS RELATED TO PATELLAR TENDON LOADING DURING A VOLLEYBALL BLOCK JUMP MOVEMENT
Get PDFPatellar tendinopathy is the most common overuse injury incurred in volleyball. Although high patellar tendon loading is thought to be a causative factor of patellar tendinopathy, it remains unknown how landing technique is related to high patellar tendon loading. Landing kinematics and patellar tendon loading were quantified for 49 volleyball players who performed a lateral stop-jump block movement. Correlations identified that volleyball players who displayed high ankle dorsiflexion velocity, high ankle dorsiflexion acceleration, and high knee flexion acceleration also generated greater peak patellar tendon force and faster patellar tendon force development. These results suggest that athletes who demonstrate rapid ankle and knee flexion when landing may be predisposed to developing patellar tendinopathy
USING VERTICAL JUMP POWER AND STANDING LONG JUMP POWER TO DETERMINE MUSCLE IMBALANCE
Get PDFThe purpose of this investigation was to determine the relationship between a ratio between vertical jump (VJ) power and standing long jump (SLJ) power and knee injury risk by using the functional power outputs with information generated from knee isokinetic testing. Medical records along with strength and conditioning testing records of 13 female NCAA-I soccer athletes were examined. Correlation and linear regressions were run to find relationships. The medical records included the isokinetic knee flexion and extension testing. Data from VJ height and SLJ distance were taken from the strength and conditioning data. Using VJ and SLJ power results to determine tendency in muscle dominance would allow development of interventions tailored to decrease the imbalance