Deep learning-based energy expenditure estimation in assisted and non-assisted gait using inertial, EMG, and heart rate wearable sensors

Energy expenditure is a key rehabilitation outcome and is starting to be used in robotics-based rehabilitation through human-in-the-loop control to tailor robot assistance towards reducing patients’ energy effort. However, it is usually assessed by indirect calorimetry which entails a certain degree of invasiveness and provides delayed data, which is not suitable for controlling robotic devices. This work proposes a deep learning-based tool for steady-state energy expenditure estimation based on more ergonomic sensors than indirect calorimetry. The study innovates by estimating the energy expenditure in assisted and non-assisted conditions and in slow gait speeds similarly to impaired subjects. This work explores and benchmarks the long short-term memory (LSTM) and convolutional neural network (CNN) as deep learning regressors. As inputs, we fused inertial data, electromyography, and heart rate signals measured by on-body sensors from eight healthy volunteers walking with and without assistance from an ankle-foot exoskeleton at 0.22, 0.33, and 0.44 m/s. LSTM and CNN were compared against indirect calorimetry using a leave-one-subject-out cross-validation technique. Results showed the suitability of this tool, especially CNN, that demonstrated root-mean-squared errors of 0.36 W/kg and high correlation (ρ > 0.85) between target and estimation (R¯2 = 0.79). CNN was able to discriminate the energy expenditure between assisted and non-assisted gait, basal, and walking energy expenditure, throughout three slow gait speeds. CNN regressor driven by kinematic and physiological data was shown to be a more ergonomic technique for estimating the energy expenditure, contributing to the clinical assessment in slow and robotic-assisted gait and future research concerning human-in-the-loop control.This work has been supported in part by the FEDER Funds through the COMPETE 2020-Programa Operacional Competitividade e Internacionalizacao (POCI) and P2020 with the Reference Project SmartOs Grant POCI-01-0247-FEDER-039868, and by FCT national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020, under the FCT scholarship with reference 2020.05708.BD, and under the Stimulus of Scientific Employment with the grant 2020.03393.CEECIND

Scapular dynamic muscular stiffness assessed through myotonometry: a narrative review

Several tools have been used to assess muscular stiffness. Myotonometry stands out as an accessible, handheld, and easy to use tool. The purpose of this review was to summarize the psychometric properties and methodological considerations of myotonometry and its applicability in assessing scapular muscles. Myotonometry seems to be a reliable method to assess several muscles stiffness, as trapezius. This method has been demonstrated fair to moderate correlation with passive stiffness measured by shear wave elastography for several muscles, as well as with level of muscle contraction, pinch and muscle strength, Action Research Arm Test score and muscle or subcutaneous thickness. Myotonometry can detect scapular muscles stiffness differences between pre- and post-intervention in painful conditions and, sometimes, between symptomatic and asymptomatic subjects.info:eu-repo/semantics/publishedVersio

WALKINSENSE VALIDATION: PRELIMINARY TESTS OF MOBILITY PARAMETERS

The purpose of this study was to perform a preliminary validation of a new electronic instrument for human movement and performance assessment in sports. Measurements of distance, walking speed, step length and frequency were acquired, for a small sample of 15 subjects in a track of 10 m length, and compared to reference data. Results show good repeatability and data agreement across several trials at three different selfselected walking speeds

13th FINA World Championships: analysis of swimsuits used by elite male swimmers

The purpose of this study was to describe the distribution of different swimsuits models used by male swimmers during all the finals at the 13th FINA World Championships, being held at Rome in 2009. Simultaneously, it was intended to verify the distribution of the different swimsuits used along the distances of the freestyle finals, and thus to understand the preferences of the top-level swimmers. It were used the results databases from the 13th FINA World Championships, in Rome 2009. Only the male swimmers participating at the finals were analyzed, for a total number of 17 individual swimming events. The wear swimsuit by each swimmer in a given event was observed from video recorded of the television broadcast. Male swimmers participating in the finals limited their choice to seven types of commercial swimsuits, of four different sports brands. Jaked01 Full® was the most used (47.07%), followed by the Powerskin X-Glide Full® (34.56%), the Powerskin X-Glide Pants® (7.35%) and the LZR Racer Full® (5.15%). In freestyle swimming events most of the male swimmers choose to wear full body swimsuits. Jaked01 Full® was predominant in the 50 m event, with 62.50% of swimmers choices. This value decreases to 25.00% when analyzing 100 m event, and remained similar over the longer distances swum. The Powerskin X-Glide Full® was used for 37.50% of the swimmers in 50 m swimming event, and it increases to 62.50% for the 100 m freestyle. These results seem to demonstrate that swimmers have preferences for full swimsuits, and for these two swimsuits, the Powerskin X-Glide Full® and the Jaked01 Full®

Wearable inertial sensor system towards daily human kinematic gait analysis: benchmarking analysis to MVN BIOMECH

This paper presents a cost- and time-effective wearable inertial sensor system, the InertialLAB. It includes gyroscopes and accelerometers for the real-time monitoring of 3D-angular velocity and 3D-acceleration of up to six lower limbs and trunk segment and sagittal joint angle up to six joints. InertialLAB followed an open architecture with a low computational load to be executed by wearable processing units up to 200 Hz for fostering kinematic gait data to third-party systems, advancing similar commercial systems. For joint angle estimation, we developed a trigonometric method based on the segments’ orientation previously computed by fusion-based methods. The validation covered healthy gait patterns in varying speed and terrain (flat, ramp, and stairs) and including turns, extending the experiments approached in the literature. The benchmarking analysis to MVN BIOMECH reported that InertialLAB provides more reliable measures in stairs than in flat terrain and ramp. The joint angle time-series of InertialLAB showed good waveform similarity (>0.898) with MVN BIOMECH, resulting in high reliability and excellent validity. User-independent neural network regression models successfully minimized the drift errors observed in InertialLAB’s joint angles (NRMSE < 0.092). Further, users ranked InertialLAB as good in terms of usability. InertialLAB shows promise for daily kinematic gait analysis and real-time kinematic feedback for wearable third-party systems.This work has been supported in part by the Fundação para a Ciência e Tecnologia (FCT) with the Reference Scholarship under Grant SFRH/BD/108309/2015 and SFRH/BD/147878/2019, by the FEDER Funds through the Programa Operacional Regional do Norte and national funds from FCT with the project SmartOs under Grant NORTE-01-0145-FEDER-030386, and through the COMPETE 2020—Programa Operacional Competitividade e Internacionalização (POCI)—with the Reference Project under Grant POCI-01-0145-FEDER-006941

Experimental solubility and density studies on aqueous solutions ofquaternary ammonium halides, and thermodynamic modelling formelting enthalpy estimations

Aiming to extend the yet limited knowledge on phase equilibria and physical-chemical properties of quaternaryalkylammonium halides and their aqueous binary systems, the solubilities of ten salts in water were measured inthis work in the temperature range between 293.2 K and 348.2 K along with their densities. The PC-SAFT equa-tion of state was thenapplied in the description of density as well as water activity coefficients data. The model-ling results describe very satisfactorily the experimental data, and the non-associating parameters follow well-defined trends with the molecular weight of the alkylammonium halides. These parameters were applied inthe prediction of the solubility data with unsatisfactory results, with mole fraction average absolute deviation(AAD= 0.018), deteriorating with increasing alkyl chain length.However, refitting thebinaryinteraction param-eter a much better description is obtained (AAD = 0.0045). COSMO-RS was also applied for the solubility predic-tion (AAD = 0.025), with poorer results for the chloride salts. After, the melting enthalpies of the quaternaryalkylammonium halides were estimated using the PC-SAFT equation, which in spite of their uncertainty, are pos-sibly the best option to perform solid-liquid equilibrium analysis of utmost importance when designing andscreening new deep eutectic mixtures based on these compounds.publishe

Caracterización de electrodos textiles para mediciones EMG: impedancia y morfología de señal

Textile electrodes are an alternative to conventional silver-chloride electrodes in wearable systems. Their easy integration in garments and comfort provided to the user make them an interesting development of textile engineering. The potential of such electrodes to allow more unobtrusive data collection in health and sports context may enable the development of biosensing garments to be used in biomechanics. However, proper validation of the recorded signals is paramount, and few studies have yet presented consistent methodologies for textile-based electromyographic recordings. This study presents the validation of the electrical and morphological properties of electromyographic signals recorded with textile electrode, in comparison to conventional silver-chloride electrodes. Results indicate that both sets of electrodes have identical signal-to-noise ratios, but with distinct impedance frequency responses. Electromyographic envelope morphologies are also identical, although textile electrodes usually have lower amplitudes.Eléctrodos têxteis são uma alternativa aos convencionais eléctrodos de cloreto de prata em sistemas vestiveis. A sua fácil integração em vestuário e o conforto que providenciam tornam-nos um interessante desenvolvimento da engenharia têxtil. O potencial destes eléctrodos para permitir a discreta recolha de dados em contexto de saúde e desporto poderá permitir o desenvolvimento de vestuário biossensivel com aplicação em biomecânica. No entanto, uma adequada validação dos sinais registados é fundamental, e poucos estudos apresentaram metodologias consistentes para registos electromiográficos baseados em elétrodos têxteis. Este estudo apresenta a validação das propriedades eléctricas e morfológicas de sinais electromiográficos registados com eléctrodos têxteis, em comparação com os convencionais eléctrodos de cloreto de prata. Os resultados indicam que ambos os eléctrodos apresentam razões sinal-ruído identicos, mas com uma resposta em frequência de impedância distincta. A morfologia do envelope electromiográfico é também identica entre electrodos, ainda que geralmente de menor amplitude no eléctrodo têxtil.Los electrodos textiles son una alternativa a los electrodos de cloruro de plata convencionales en los sistemas portátiles. Su fácil integración en las vestimentas y la comodidad que brinda al usuario las convierten en un interesante desarrollo de la ingeniería textil. El potencial de tales electrodos para permitir una recopilación de datos más discreta en el contexto de la salud y el deporte puede permitir el desarrollo de vestimentas biosensibles para su uso en biomecánica. Sin embargo, la validación adecuada de los señales registradas es primordial y pocos estudios han presentado metodologías consistentes para registros electromiográficos basados en textiles. Este estudio presenta la validación de las propiedades eléctricas y morfológicas de señales electromiográficas registradas con electrodo textil, en comparación con electrodos convencionales de cloruro de plata. Los resultados indican que ambos los electrodos tienen relaciones señal-ruido idénticas, pero con una respuesta de frecuencia de impedancia distinta. La morfología de la envoltura electromiográfica también se identifica entre electrodos, aunque generalmente de menor amplitud en el electrodo textil

The influence of gait cadence on the ground reaction forces and plantar pressures during load carriage of young adults

Biomechanical gait parameters ground reaction forces (GRFs) and plantar pressures during load carriage of young adults were compared at a low gait cadence and a high gait cadence. Differences between load carriage and normal walking during both gait cadences were also assessed. A force plate and an in-shoe plantar pressure system were used to assess 60 adults while they were walking either normally (unloaded condition) or wearing a backpack (loaded condition) at low (70 steps per minute) and high gait cadences (120 steps per minute). GRF and plantar pressure peaks were scaled to body weight (or body weight plus backpack weight). With medium to high effect sizes we found greater anterior-posterior and vertical GRFs and greater plantar pressure peaks in the rearfoot, forefoot and hallux when the participants walked carrying a backpack at high gait cadences compared to walking at low gait cadences. Differences between loaded and unloaded conditions in both gait cadences were also observed.info:eu-repo/semantics/acceptedVersio

Cytotoxicity of Portuguese propolis: the proximity of the in vitro doses for tumor and normal cell lines

With a complex chemical composition rich in phenolic compounds, propolis (resinous substance collected by Apis mellifera from various tree buds) exhibits a broad spectrum of biological activities. Recently, in vitro and in vivo data suggest that propolis has anticancer properties, but is the cytoxicity of propolis specific for tumor cells? To answer this question, the cytotoxicity of phenolic extracts from Portuguese propolis of different origins was evaluated using human tumor cell lines (MCF7-breast adenocarcinoma, NCI-H460-non-small cell lung carcinoma, HCT15-colon carcinoma, HeLa-cervical carcinoma, and HepG2-hepatocellular carcinoma), and non-tumor primary cells (PLP2). The studied propolis presented high cytotoxic potential for human tumor cell lines, mostly for HCT15. Nevertheless, excluding HCT15 cell line, the extracts at the GI50 obtained for tumor cell lines showed, in general, cytotoxicity for normal cells (PLP2). Propolis phenolic extracts comprise phytochemicals that should be further studied for their bioactive properties against human colon carcinoma. In the other cases, the proximity of the in vitro cytotoxic doses for tumor and normal cell lines should be confirmed by in vivo tests and may highlight the need for selection of specific compounds within the propolis extract.The authors are grateful to Foundation for Science and Technology (FCT), Portugal, for providing the financial support to the research centers CIMO (PEst-OE/AGR/UI0690/2011) and CQ-UM (PEst-C/QUI/UI0686/2011). Ricardo C. Calhelha thanks FCT, POPH-QREN, and FSE for his Grant (SFRH/BPD/68344/2010). Thanks are also due to the National Federation of Portuguese Beekeepers for supplying propolis samples

THE STUDY OF SWIMMERS’S HAND AND FOREARM USING COMPUTATIONAL FLUID DYNAMICS

Computational Fluid Dynamics has been widely used in biomechanics studies applied to medicine and sport. In this study we developed a 3-D model for swimmer’s hand/forearm forces using Computational Fluid Dynamics. Models used in the simulations were created in CAD, based on realistic dimensions of a right adult human hand/forearm. The governing system of equations considered was the incompressible Reynolds averaged Navier-Stokes equations implemented with Fluent® code. The drag coefficient was the main responsible for propulsion, with a maximum value of force propulsion corresponding to a pitch angle of 90º. The lift coefficient seemed to play a less important role in the generation of propulsive force with pitch angles of 0º and 90º but it is important with a pitch angle of 45º. It was demonstrated the relevance of applying CFD in the propulsive force measurements, using a more realistic model of a human segment