28 research outputs found

    Design and manufacturing of prosthetic feet for children as a multidisciplinary project for mechanical engineering students

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    The authors would like to thank all colleagues that helped with the setup of this project, but also all the student groups from ENSAM and EPF engineering school that participated in this pedagogical project. More particularly the students of the “apprentissage” who helped to design the fatigue testing machine which is a next step for this work. And, also Eve Bennett who helped for the writing of English.This paper presents the development of a prosthetic foot designed by engineering-school students. A complete workflow from needs definition to the production and testing was performed. The standards for adults were adapted to children, then a pre-design was performed, and a numerical model was realised to perform numerical testing. The production was carried out through additive manufacturing and the printed prosthetics were tested in flexion, and then in a motion analysis room. This project was aimed at making students put into practice their ability to design and test a mechanical product in a biomechanics context. Their learning outcomes were assessed during their oral presentations, their written reports and the testing session. Students gave positive feedback at the end of the semester about their feeling of the project

    Biomechanical analysis of the golf swing: methodological effect of angular velocity component on the identification of the kinematic sequence

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    The golf swing is a complex whole-body motion for which a proximal-to-distal transfer of the segmental angular velocitiesfrom the pelvis to the club is believed to be optimal for maximizing the club head linear velocity. However, previous experimental resultsabout such timing (or kinematic sequence) are contradictory. Nevertheless, methods that were used in these studies differed significantly,in particular, those regarding the component of the angular velocity vector selected for the identification of the kinematic sequence.Hence, the aim of this study was to investigate the effect of angular velocity vector component selection on the identified kinematicsequence. Methods: Thirteen golfers participated in this study and performed driver swings in a motion capture laboratory. Seven meth-ods based on different component selection of segmental angular velocities (vector norm, component normal-to-sagittal, frontal, trans-versal and swing planes, segment longitudinal component and a method mixing longitudinal and swing plane components) were tested.Results: Results showed the critical influence of the component chosen to identify the kinematic sequence with almost as many kine-matic sequences as the number of tested methods for every golfer. Conclusion: One method seems to show the strongest correlation toperformance but none of them can be assessed as a reference method for the identification of the golf swing kinematic sequence. Re-garding the limited time lag between the different peak occurrences and the uncertainty sources of current materials, development ofsimulation studies would be more suitable to identify the optimal kinematic sequence for the golf swin

    Effect of shoulder model complexity in upper-body kinematics analysis of the golf swing

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    The golf swing is a complex full body movement during which the spine and shoulders are highly involved. In order to determine shoulder kinematics during this movement, multibody kinematics optimization (MKO) can be recommended to limit the effect of the soft tissue artifact and to avoid joint dislocations or bone penetration in reconstructed kinematics. Classically, in golf biomechanics research, the shoulder is represented by a 3 degrees-of-freedom model representing the glenohumeral joint. More complex and physiological models are already provided in the scientific literature. Particularly, the model used in this study was a full body model and also described motions of clavicles and scapulae. This study aimed at quantifying the effect of utilizing a more complex and physiological shoulder model when studying the golf swing. Results obtained on 20 golfers showed that a more complex and physiologically-accurate model can more efficiently track experimental markers, which resulted in differences in joint kinematics. Hence, the model with 3 degrees-of-freedom between the humerus and the thorax may be inadequate when combined with MKO and a more physiological model would be beneficial. Finally, results would also be improved through a subject-specific approach for the determination of the segment lengths

    Evaluation of Physical Interaction during Walker-Assisted Gait with the AGoRA Walker: Strategies Based on Virtual Mechanical Stiffness

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    Smart walkers are commonly used as potential gait assistance devices, to provide physical and cognitive assistance within rehabilitation and clinical scenarios. To understand such rehabilitation processes, several biomechanical studies have been conducted to assess human gait with passive and active walkers. Several sessions were conducted with 11 healthy volunteers to assess three interaction strategies based on passive, low and high mechanical stiffness values on the AGoRA Smart Walker. The trials were carried out in a motion analysis laboratory. Kinematic data were also collected from the smart walker sensory interface. The interaction force between users and the device was recorded. The force required under passive and low stiffness modes was 56.66% and 67.48% smaller than the high stiffness mode, respectively. An increase of 17.03% for the hip range of motion, as well as the highest trunk’s inclination, were obtained under the resistive mode, suggesting a compensating motion to exert a higher impulse force on the device. Kinematic and physical interaction data suggested that the high stiffness mode significantly affected the users’ gait pattern. Results suggested that users compensated their kinematics, tilting their trunk and lower limbs to exert higher impulse forces on the device

    Influence of the projection plane and the markers choice on the X-factor computation of the golf swing X-factor: a case study

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    Study of variability induced by the methology choice on the X-factor computation of the golf swing. Based on optoelectronic measurements. Variability of the choice of upper limb, plane of projection and instant of computation

    Variability of motor moment during golf swing: study of a female professional player

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    Study of th intra-individual variability of the motor moment during the golf swing. It highlighted the variability induced by horizontal ground reaction forces which are rarely taken into account in field

    Effect of Horizontal Ground Reaction Forces during the Golf Swing: Implications for the development of technical solutions of golf swing analysis

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    The swing is a key movement for golf. Its in-field performance could be estimated by embedded technologies, but often only vertical ground reaction forces (VGRF) are estimated. However, as the swing plane is inclined, horizontal ground reaction forces (HGRF) are expected to contribute to the increase of the club angular velocity. Thus, this study aimed at investigating the role of the HGRF during the golf swing. Twenty-eight golf players were recruited and performed 10 swings with their own driver club, in a motion analysis laboratory, equipped with a full body marker set. Ground reaction forces (GRF) were measured with force-plates. A multibody kinematic optimization was performed with a full body model to estimate the instantaneous location of the golfer’s center of mass (CoM). Moments created by the GRF at the CoM were investigated. Results showed that horizontal forces should not be neglected regarding to VGRF because of their lever arm. Analyzing golf swing with only VGRF appeared not enough and further technological developments are still needed to ecologically measure other components
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