HOW MULTILEVEL BIOMECHANICAL MODELLING CAN HELP UNDERSTANDING SPORT MOVEMENT AND DESIGNING SPORT EQUIPMENT

Analysing the complete influence of a sport equipment is highly difficult due to its multifactorial nature (covering physiology, biomechanics, motor control, and psychology). Indeed, changing the sport equipment can deeply modify the performance, in terms of absolute timing (lower running or cycling speed for example), by changing the way the musculoskeletal system is solicited or by favouring related-injuries. In this presentation, two points will be addressed. First, musculoskeletal modelling (EMGDriven model) will be used to understand how wearing a running shoe can affect the muscle and tendon behaviours during the activity. Second, a finite elements model of the shod foot driven by experimentally-estimated muscle forces will be presented. This model can be used to numerically simulate modifications of the running shoe characteristics and assess their influences over the strain and stress of the different structures of the foot. These points will cover both fundamental and applied aspects in sport sciences

A KINEMATIC AND DYNAMIC ANALYSIS OF ELITE ALPINE SKIERS

The knowledge of the internal forces and torques acting on a joint during a physical activity as well as a clear description of the motion performed by an elite athlete is of top most interest for rehabilitation, teaching or training purposes. Nevertheless, the motion of the athletes can be strongly affected by the evolution of the equipment design. For example, great changes in terms of angular motion and ground reaction have been revealed in alpine skiing when comparing conventional and carving turns (Yoneyama, 2000). More recently, MCJller and Schwameder (2003) have carried out a comparative study between conventional and carving ski turn based upon kinematics, plantar pressure and EMG records. Coupling 3D video analysis and forceplate acquisition, the present work aims at recording the displacements of whole body segments as well as ground reaction in order to analyze the turning motion of elite alpine skiers

NEUROMECHANICS OF CYCLING: OPPORTUNITIES FOR OPTIMIZING PERFORMANCE

From the very simple (external power output) to the more complex variables (effective force profile, index of effectiveness, specific joint power) up to a neuro-musculo-skeletal integrative approach, we will focus on the following items: a clear definition of each concepts and variables, the tools needed for its accurate measurement and the state of scientific knowledge (and/or illustration) about its potential interest for the cycling performance. The ultimate approach using musculoskeletal models will also be mentioned just to give an idea of the potential interest to use them in a cycling performance enhancement endeavor

An SDN Perspective on Multi-connectivity and Seamless Flow Migration

Devices capable of multi-connectivity currently use static rules for selecting the set of interfaces to use. Such rules are limited in scope and can be counter-productive. We posit that SDN techniques can address this inefficiency. We present an approach that enables an SDN controller to manage the flows traversing the Ethernet, Wi-Fi, and LTE links in our laptop and also migrate the flows from one link to another. Our solution opens avenues that enable end-user device to negotiate with the network controllers when taking its control plane decisions.Peer reviewe

Preclinical evaluation of the atraumatic nature of a spring loaded blunt tip coaxial needle in a swine model

International audiencePurpose: To test in vivo in an animal model the inherent atraumatic characteristics of the spring loaded blunt tip of a coaxial needle (Gangi-SoftGuard®, Apriomed, Sweden) against a conventional sharp stylet coaxial needle.Material and Methods: The study was conducted on a 40 kg male swine that was its own control for a vascular trauma model. The procedure consisted of voluntary attempts to transfix and traverse the artery/aorta under continuous real-time angiogram. Test and control needles were positioned in the region of the intercostal, superior mesenteric and femoral/deep femoral arteries, and in the aorta. Computed tomography (CT) angiogram was performed post trauma to check for bleeding in the form of extravasation of contrast material. One attempt was performed per site and needle, except for the intercostal artery where a second attempt was done with the test needle, resulting in a total of 4 and 5 tests for the control and test needles, respectively.Results: With the spring loaded blunt tip, no vascular trauma or bleeding was noted in the intercostal, superior mesenteric and femoral arteries, nor in the aorta. Vascular spasm that recovered with time was noted during the second attempt to transfix the same intercostal artery. There were consistent vascular traumas and bleedings with the control needle in all three tested arteries and the aorta, confirmed on angiogram as well as CT angiogram.Conclusion: The atraumatic feature offered by the spring loaded blunt tip prevented vascular trauma during the 5 attempts made to transfix the artery/aorta in a swin

Is Motorized Treadmill Running Biomechanically Comparable to Overground Running? A Systematic Review and Meta-Analysis of Cross-Over Studies

Background Treadmills are often used in research, clinical practice, and training. Biomechanical investigations comparing treadmill and overground running report inconsistent findings. Objective This study aimed at comparing biomechanical outcomes between motorized treadmill and overground running. Methods Four databases were searched until June 2019. Crossover design studies comparing lower limb biomechanics during non-inclined, non-cushioned, quasi-constant-velocity motorized treadmill running with overground running in healthy humans (18-65 years) and written in English were included. Meta-analyses and meta-regressions were performed where possible. Results 33 studies (n = 494 participants) were included. Most outcomes did not differ between running conditions. However, during treadmill running, sagittal foot-ground angle at footstrike (mean difference (MD) − 9.8° [95% confidence interval: − 13.1 to − 6.6]; low GRADE evidence), knee flexion range of motion from footstrike to peak during stance (MD 6.3° [4.5 to 8.2]; low), vertical displacement center of mass/pelvis (MD − 1.5 cm [− 2.7 to − 0.8]; low), and peak propulsive force (MD − 0.04 body weights [− 0.06 to − 0.02]; very low) were lower, while contact time (MD 5.0 ms [0.5 to 9.5]; low), knee flexion at footstrike (MD − 2.3° [− 3.6 to − 1.1]; low), and ankle sagittal plane internal joint moment (MD − 0.4 Nm/kg [− 0.7 to − 0.2]; low) were longer/higher, when pooled across overground surfaces. Conflicting findings were reported for amplitude of muscle activity. Conclusions Spatiotemporal, kinematic, kinetic, muscle activity, and muscle-tendon outcome measures are largely comparable between motorized treadmill and overground running. Considerations should, however, particularly be given to sagittal plane kinematic differences at footstrike when extrapolating treadmill running biomechanics to overground running

Cognitive performance in relapsing remitting multiple sclerosis: A longitudinal study in daily practice using a brief computerized cognitive battery

<p>Abstract</p> <p>Background</p> <p>There is need for a cognitive test battery that can be easily used in clinical practice to detect or monitor cognitive performance in patients with multiple sclerosis (MS). In order to conduct, in this patient group, a preliminary investigation of the validity and utility of a brief computerized battery, the Cognitive Drug Research (CDR) battery, we longitudinally assessed cognition in patients with relapsing remitting (RR) MS.</p> <p>Methods</p> <p>Forty-three mildly disabled, clinically active RRMS patients were repeatedly assessed with the Digit Symbol Substitution Test (DSST), Paced Auditory Serial Addition Test (PASAT) and five composite scores derived from the CDR computerized cognitive test system (CDR System): Power of Attention, Continuity of Attention, Quality of Working Memory, Quality of Episodic Memory and Speed of Memory. The Multiple Sclerosis Functional Composite (MSFC) and Expanded Disability Status Scale (EDSS) measured disability.</p> <p>Results</p> <p>The composite scores from the CDR battery generally showed excellent test-retest reliability over the repeated assessments, though was low on occasions for the Quality of Working Memory and Quality of Episodic Memory measures. The CDR measures tended to be highly correlated with other measures of cognition (DSST and PASAT) and were also strongly related to disability (EDSS and MSFC). Baseline scores indicated large impairments to visual information processing speed and attention (DSST, Cohen's d 1.1; Power of Attention d 1.4 [reaction time on tasks of focussed and sustained attention]), and a moderate impairment both to sustained attention (Continuity of Attention d 0.6) and complex information processing speed (Speed of memory d 0.7 [reaction time on tasks of working and episodic Memory]), when compared to normative data derived from healthy volunteers enrolled in a series of separate, prior clinical trials. Working memory (Quality of Working Memory) and episodic memory (Quality of Episodic Memory) were unimpaired.</p> <p>Conclusions</p> <p>Preliminary validation of the CDR System indicated that for most, but not all measures psychometric properties were adequate and the measures were related to disability (EDSS and MSFC) and other measures of cognition.</p

SMARCB1 regulates a TFCP2L1-MYC transcriptional switch promoting renal medullary carcinoma transformation and ferroptosis resistance

Renal medullary carcinoma (RMC) is an aggressive tumour driven by bi-allelic loss of SMARCB1 and tightly associated with sickle cell trait. However, the cell-of-origin and oncogenic mechanism remain poorly understood. Using single-cell sequencing of human RMC, we defined transformation of thick ascending limb (TAL) cells into an epithelial-mesenchymal gradient of RMC cells associated with loss of renal epithelial transcription factors TFCP2L1, HOXB9 and MITF and gain of MYC and NFE2L2-associated oncogenic and ferroptosis resistance programs. We describe the molecular basis for this transcriptional switch that is reversed by SMARCB1 re-expression repressing the oncogenic and ferroptosis resistance programs leading to ferroptotic cell death. Ferroptosis resistance links TAL cell survival with the high extracellular medullar iron concentrations associated with sickle cell trait, an environment propitious to the mutagenic events associated with RMC development. This unique environment may explain why RMC is the only SMARCB1-deficient tumour arising from epithelial cells, differentiating RMC from rhabdoid tumours arising from neural crest cells