Using microtechnology to quantify torso angle during match-play in field hockey

Warman, GE, Cole, MH, Johnston, RD, Chalkley, D, and Pepping, GJ. Using microtechnology to quantify torso angle during match-play in field hockey. J Strength Cond Res 33(10): 2648–2654, 2019—Field hockey is played in a dynamic environment placing specific postural demands on athletes. Little research has been devoted to understanding the nature of a player's torso postures in field hockey match-play and its relationship with the perceptuomotor demands of the sport. We used commercially available microtechnology worn by 16 athletes during a 6-match national tournament to quantify torso flexion/extension angles. Orientation was derived using the inertial and magnetic sensors housed within global positioning system devices, assessing torso angle in the sagittal plane from 91 individual match files. The main independent variable was playing position, whereas the dependent variable was torso flexion/extension, presented as a percentage of playing time spent in 15 × 10° torso postural bands ranging from ≥40° extension to ≥90° flexion. It was shown that athletes spent 89.26% of their playing time in various torso postures, ranging from 20 to 90° of flexion. Defenders spent more time than midfielders (p = 0.004, effect size [ES] = 0.43) and strikers (p = 0.004; ES = 0.44) in the posture band of 10–20° torso flexion, whereas midfielders spent more time between 20 and 30° of torso flexion (p = 0.05; ES = 0.32) than strikers. Conversely, strikers spent more time between 30 and 40° of flexion than defenders (p < 0.001; ES = 0.74). These results reflect the sport-specific and role-specific torso angles adopted by field hockey athletes during match-play. Coaching staff can use these data to gain insight into the postural demands of their sport and inform the preparation of athletes for the perception-action demands of competition

Optimisation of the Rugby Wheelchair for Performance

Equipment design in para-sport has a substantial impact on athlete performance. Subsequently, wheelchair designs have progressed to reflect the requirements of their sports; for wheelchair rugby, this has resulted in features including reinforced frames to withstand the frequent high impacts and cambered wheels for improved agility and stability. Whilst these aspects of wheelchair design have advanced, there is currently no accepted method for optimising an individual’s wheelchair configuration (e.g., setting of seat height/seat angle); instead, players rely on their previous experience and support staff in trial-and-error approaches to prescribing set-ups. This is likely due to a number of factors, including: the range of impairment types and severities in the sport, hence optimal set-ups differing across players; difficulty in assessing on-court performance and propulsion kinematics; limited knowledge of the effects of set-up parameters on key performance and propulsion factors; and the substantial time and cost associated with new chair prescriptions. To address this issue, this research aims to improve the knowledge regarding the effect configuration parameters have on performance and propulsion in wheelchair rugby. To achieve this, an improved understanding of current player set-ups and their propulsion approaches is required. Large participant groups (n=16 and 25, for set-up and propulsion analysis respectively) allowed for statistical assessments based on classification groups (high-, mid-, and low-point groups). Significant differences were found in both set-up and propulsion approaches across classifications. The majority of these differences reflect the levels of the player’s activity limitation (i.e., high-point players with greater trunk range of motion used flatter seat angles, and contacted the wheel closer to top dead centre than low-point players). Additionally, a potential trend towards increasing release angles and greater peak accelerations was identified. More detailed individual assessments of propulsion were also performed that revealed variations in intra-stroke acceleration profiles of three players. This information can aid in wheelchair prescription by identifying regions of strength for an individual, with this then emphasised by the wheelchair set-up. To assess the effect of set-up parameters on performance and propulsion measures, a robust design approach using an adjustable wheelchair was implemented with six elite players. This approach required reduced amounts of field testing whilst maintaining the ability to identify the effect of the specific settings of seat height, seat depth, seat angle, and tyre pressure. Half the players reported a blinded preference for a recommended set-up following this testing, while remaining players reported a preference based on ‘comfort’ despite similar results. Finally, a linkage model and regression approach were developed that accounted for individual anthropometrics, propulsion approach, and wheelchair set-up and successfully predicted a performance measure for some players. Overall, this research has improved the knowledge surrounding the effect of wheelchair rugby set-up parameters on performance and propulsion at both group and individual levels. Optimisation of wheelchair set-up should occur at an individual level and consider functional abilities and on-court role; approaches such as the robust design and modelling methods presented in this thesis improve the ability to achieve this in practise.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 201

Social work with airports passengers

Social work at the airport is in to offer to passengers social services. The main methodological position is that people are under stress, which characterized by a particular set of characteristics in appearance and behavior. In such circumstances passenger attracts in his actions some attention. Only person whom he trusts can help him with the documents or psychologically

Postures et mouvements du membre supérieur à partir de capteurs inertiels : une évaluation méthodologique

This PhD work is focused on the estimation of joint angles and segment positions of the upper limb based on inertial sensor technology (MIMU). Despite much interest from the scientific community in this topic, several aspects of research deserve more investigation. This work contributes to the enhancement of scientific knowledge related to (1) the kinematic modeling associated to MIMU and (2) the validation of final kinematic outputs (joint angles and segment positions). Based on an exhaustive methodological approach, recommendations related to the anatomical calibration of MIMU are highlighted. Moreover, key-values related to the characterization of kinematic outputs are proposed, such as a precision of joint angles of 5-10° and a hand positioning error of 7-15 cm. The aim of this study is the development of an ambulatory system for the assessment of postures and movements of the upper limb, in a general context of musculoskeletal disorders risk assessment at work. From now on, an advanced kinematic modeling that uses a MIMU placed on the scapula as well as a characterization of the system under magnetic disturbances represent two of the main scientific questions to exploreCe travail de thèse s’intéresse à l’estimation des angles articulaires et des positions segmentaires du membre supérieur à partir de capteurs inertiels (MIMU). Malgré l’intérêt grandissant de la communauté scientifique pour cette technologie, plusieurs questions de recherche restent en suspens. Ce travail de thèse contribue à l’avancée de connaissances scientifiques à la fois au niveau de la modélisation cinématique du membre supérieur associée aux capteurs inertiels et au niveau de la validation même des données cinématiques de sortie (angles articulaires et positions segmentaires). Au travers d’une approche méthodologique complète, des recommandations de calibration anatomique sont avancées. De plus, des valeurs clefs de caractérisation sont proposées, telles qu’une reproductibilité des données angulaires de l’ordre de 5-10° et une erreur de positionnement de la main de 7-15 cm. La finalité de ce travail de thèse est la mise à disposition d’un système ambulatoire pour l’évaluation des postures et des mouvements du membre supérieur dans une optique d’évaluation des risques de troubles musculo-squelettiques en milieu professionnel. Une modélisation cinématique avancée prenant en compte un capteur inertiel sur la scapula et la caractérisation du système en milieu perturbé magnétiquement apparaissent comme une suite logique à ce travail de thès

A Novel AHRS Inertial Sensor-Based Algorithm for Wheelchair Propulsion Performance Analysis

With the increasing rise of professionalism in sport, athletes, teams, and coaches are looking to technology to monitor performance in both games and training in order to find a competitive advantage. The use of inertial sensors has been proposed as a cost effective and adaptable measurement device for monitoring wheelchair kinematics; however, the outcomes are dependent on the reliability of the processing algorithms. Though there are a variety of algorithms that have been proposed to monitor wheelchair propulsion in court sports, they all have limitations. Through experimental testing, we have shown the Attitude and Heading Reference System (AHRS)-based algorithm to be a suitable and reliable candidate algorithm for estimating velocity, distance, and approximating trajectory. The proposed algorithm is computationally inexpensive, agnostic of wheel camber, not sensitive to sensor placement, and can be embedded for real-time implementations. The research is conducted under Griffith University Ethics (GU Ref No: 2016/294)

Actas de las XXXIV Jornadas de Automática

Postprint (published version