D. Bibbo - Profile on Academia.edu (original) (raw)

Papers by D. Bibbo

Anticipatory responses characterize the Alzheimer’s Disease continuum in a reaching task

Gait & Posture

Position-specific muscle coactivation in human-robot collaboration

Gait & Posture

Human Body Energy Harvesting Solutions for Wearable Technologies

2018 IEEE 20th International Conference on e-Health Networking, Applications and Services (Healthcom), 2018

The paper presents an overview of recent and noninvasive technologies used to harvest electrical ... more The paper presents an overview of recent and noninvasive technologies used to harvest electrical energy on the surfaces of human body. New electronic materials developed to provide sufficient comfort for the people wearing them are analyzed, and an inventory of common sensors for monitoring applications, which can profit from these technologies, is provided. In this way, a comprehensive panorama of what is currently available to design ultra-low-power systems is given. The purpose of the paper is to provide the basis for the development of non-invasive wearable devices, powered by the energy harvested on the surfaces of human body, which consider wearability and comfort constraints.

Published online before print June 30, 2014, doi: 10.1123/jab. 2013-0317 Journal of 2 Applied Biomechanics 3

Neuromuscular adaptations during submaximal prolonged cycling

Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2012

This study aims at evaluating the neuromuscular adaptations occurring during submaximal prolonged... more This study aims at evaluating the neuromuscular adaptations occurring during submaximal prolonged cycling tasks. In particular, we want to assess changes in surface electromyographic (sEMG) signal recorded during a pedaling task, performed by six subjects on a cycle-simulator at a constant power output, until voluntary exhaustion. Task failure was defined as the instant the subject was no longer able to maintain the required task. Electromyographic activity was recorded from eight muscles of the dominant leg and burst characteristics of sEMG signals were analyzed in order to assess the changes in muscle activity level produced by the occurrence of neuromuscular fatigue. In particular, three features were extracted from the sEMG signal for each burst: amplitude, location of the maxima and mean profile of the burst envelope. We have reported an increase in the amplitude parameter for all subjects only for Vastii while bi-articular muscles presented a high variability among subjects. Also the location of the maximal values of the mean envelope of the bursts was found to change when considering bi-articular or mono-articular muscles. The envelope profile was found not to be subject to alterations when comparing the end of the task with the beginning. We speculated that neuromuscular fatigue induces changes essentially in the mono-articular muscles which produce power. This phenomenon is highly correlated with the adopted pedaling strategy which, being not constrained, induces subjects to express the maximal power in the downstroke phase, related to knee extension and involving mainly mono-articular muscles.

Analysis of different image-based biofeedback models for improving cycling performances

Proceedings of SPIE - The International Society for Optical Engineering, 2012

abstract Sport practice can take advantage from the quantitative assessment of task execution, wh... more abstract Sport practice can take advantage from the quantitative assessment of task execution, which is strictly connected to the implementation of optimized training procedures. To this aim, it is interesting to explore the effectiveness of biofeedback training techniques. This implies a complete chain for information extraction containing instrumented devices, processing algorithms and graphical user interfaces (GUIs) to extract valuable information (ie kinematics, dynamics, and electrophysiology) to be presented in real-time ...

Inter-individual variability of forces and modular muscle coordination in cycling: A study on untrained subjects

Human Movement Science, 2013

The aim of this study was to investigate the muscle coordination underlying pedaling in untrained... more The aim of this study was to investigate the muscle coordination underlying pedaling in untrained subjects by using the muscle synergies paradigm, and to connect it with the inter-individual variability of EMG patterns and applied forces. Nine subjects performed a pedaling exercise on a cycle-simulator. Applied forces were recorded by means of instrumented pedals able to measure two force components. EMG signals were recorded from eight muscles of the dominant leg, and Nonnegative Matrix Factorization was applied to extract muscle synergy vectors W and time-varying activation coefficients H. Inter-individual variability was assessed for EMG patterns, force profiles, and H. Four modules were sufficient to reconstruct the muscle activation repertoire for all the subjects (variance accounted for &amp;amp;amp;amp;amp;amp;amp;gt;90% for each muscle). These modules were found to be highly similar between subjects in terms of W (mean r=.89), while most of the variability in force profiles and EMG patterns was reflected, in the muscle synergy structure, in the variability of H. These four modules have a functional interpretation when related to force distribution along the pedaling cycle, and the structure of W is shared with that present in human walking, suggesting the existence of a modular motor control in humans.

A wireless instrumented pedal to measure force during cycling

Proceedings 1st Mediterranean Conference on Measurement, 2004

Human Movement Analysis is generally performed through the exploitation of stereophotogrammetric ... more Human Movement Analysis is generally performed through the exploitation of stereophotogrammetric systems that rely on the use of markers [3]. With these systems, it is possible to reconstruct the trajectories of reflecting objects allocated on specific points of the human body and it is possible to reconstruct limb kinematics through the calibration parameters. In order to reduce measuring errors and artefacts dedicated algorithms are used. The performance of these systems are evaluated through the accuracy of kinematics ...

System for Evaluating the Pedalling Efficiency of a Cyclist

Abstract: Described herein is a system (6) for evaluating the pedalling efficiency of a cyclist, ... more Abstract: Described herein is a system (6) for evaluating the pedalling efficiency of a cyclist, comprising: means (16, 18, 19; 106) for detecting'at least one quantity regarding pedalling by said cyclist, which are coupled with a pedal (5), which is in turn coupled to a pedal crank (4) of a bicycle (1), and electronic processing means (10), connected to said means (16, 18, 19; 106) for detecting said quantity regarding pedalling by the cyclist, configured for determining a quantity indicating the pedalling efficiency of said cyclist.

Human Movement Science, 2004

The aim of the central nervous system in upright stance is to control an intrinsically unstable p... more The aim of the central nervous system in upright stance is to control an intrinsically unstable plant. Internal disturbances, such as haemodynamics and respiration, constitute an endogenous threat to equilibrium. The way CNS reacts to those perturbations was studied in this work, through the analysis of summary scores taken from posturographic and pneumographic data. Signals were recorded simultaneously during trials administered on a sample population of healthy young adults, while sitting and standing and at paced and spontaneous uncontrolled breathing. The extraction of posturographic and pneumographic parameters was accompanied by the utilization of techniques for the detection of phase synchronization in bivariate data, and the extraction of an interaction index, the mutual information MI. The effects of the biomechanical condition and respiratory amplitude on MI and summary measures were tested with a two-way ANOVA. Summary scores clearly depend on posture condition. Synchronization between breath and postural sway is always present, depends on both biomechanical condition and respiratory threat, and cannot be reduced to a simple linear relation.

A Novel Technique to Design and Optimize Performances of Custom Load Cells for Sport Gesture Analysis

IRBM

Abstract Background The assessment of the force exerted during a gesture in human motion analysis... more Abstract Background The assessment of the force exerted during a gesture in human motion analysis can provide direct and indirect information regarding the expended energy, especially during the execution of a sport gesture. In this field, assessment and improvement of the performance can be supported by instrumented devices able to measure and process mechanical quantities. In cycling, strain gauges-based instrumented pedals represent one of the last innovations in the sector, because they can provide data about the power exerted (produced) during training and the pedal efficiency. Optimization of the strain-gauges positioning is thus required to improve accuracy in the exerted force estimation. Methods A new technique to give a support for evaluating the best compromise between maximum sensitivity and ease of assembly was developed in the present work, based on a Finite Element Model (FEM) and a parametric analysis of the strain field at different sensor placements. Optimal positions were identified as those combining high sensitivity and low dependence from positioning inaccuracies. Results Parametric strain-load trends obtained from the developed model show a linear behavior of strain gauges pairs and confirm that there is a good sensitivity of the adopted sensors if they are mounted in handy positions of the developed load cell. Discussion The conducted analysis enables to calculate the sensitivity of the load cell to the exerted forces, and evaluates its dependence to the positioning of strain gauges, and makes it possible to appropriately choose strain gauges positioning in areas where border effects are minimized. The strain distributions obtained by the FEM analysis in the presented load cells gives useful indications for all the situations where small strain gauges are requested to be mounted on a reduced offered area.

Feedback of mechanical effectiveness related adaptations in muscle synergies during cycling

A new microcontroller-based system to optimize the digital conversion of signals originating from load cells built-in into pedals

During cycling, the measurement of forces exerted on the pedal is used to monitor the level of tr... more During cycling, the measurement of forces exerted on the pedal is used to monitor the level of training and to maximize the efficiency of pedaling. In rehabilitation, the force measurement can be used to monitor the functional recovery of a patient during a therapy. In these situations, it is useful to quantify with high resolution these variables. In this work a solution to remove the DC offset at the input of an AD converter for force measurement systems, based on strain gauges load cells, is presented. This circuit has been integrated into a device used in sports and in rehabilitation contexts, that relies on a couple of cycling instrumented pedals. The system designed in this work aims at obtaining these results in a simple way and with its complete integration into the control circuit of the instrumented pedals.

Efficacy of TtB-Based Visual Biofeedback in Upright Stance Trials

IFMBE Proceedings, 2014

ABSTRACT Several studies have shown the effect of visual biofeedback (VBF) on postural control wi... more ABSTRACT Several studies have shown the effect of visual biofeedback (VBF) on postural control with real-time presentation of centre of pressure (CoP). However, up to now no study has yet focussed on the effect that a predictive VBF could have on postural control. The aim of this study is thus to determine whether the Time-to-Boundary function (TtB) could be used as an efficacious VBF in static posturography. The CoP coordinates were extracted from force plate data and elaborated to calculate TtB in real-time. Two groups of six healthy young subjects executed the protocol in two different sequences composed of the following conditions: noVBF-VBF1 (real-time presentation of CoP) and noVBF-VBF2 (real-time TtB presentation). Each condition was repeated three times. The effect of the two VBFs was studied by five parameters extracted directly from CoP coordinates (sway area, sway path, mean amplitude, frequency bandwidth that contains 95% of the power spectral density of antero-posterior and medio-lateral displacement) and two parameters by fraction Brownian motion model (exponential radial terms Hrs and Hrl corresponding to the short-term and long-term region Hurst exponents). The comparison between the VBF conditions didn’t show significant differences in the studied parameters. This evidence suggests that the participants react in similar way in both conditions, and it opens the possibility of using a predictive VBF as a tool to facilitate postural control in upright stance.

Biomedical Engineering / 817: Robotics Applications, 2014

This paper investigates how different window sizes for feature extraction and classification affe... more This paper investigates how different window sizes for feature extraction and classification affect the accuracy of daily living locomotors activity recognition through accelerometers. A comprehensive data set was collected from 9 healthy subjects performing walk, stair descending and stair ascending while carrying an accelerometer on the waist. Nearest neighbor based classification has been used because of its simplicity and flexibility. The findings show that, by increasing window length, the system accuracy increases, but it produces delays in real time detection/alert of the activity. From the experiments it is concluded that a 2 seconds (2 s) time window may represent a trade-off for the detection of these mentioned activities in a real-time scenario, as it produces 91.7 percent of accuracy.

Algorithms, 2014

This paper documents the research towards the development of a system based on Artificial Neural ... more This paper documents the research towards the development of a system based on Artificial Neural Networks to predict muscle force patterns of an athlete during cycling. Two independent inverse problems must be solved for the force estimation: evaluation of the kinematic model and evaluation of the forces distribution along the limb. By solving repeatedly the two inverse problems for different subjects and conditions, a training pattern for an Artificial Neural Network was created. Then, the trained network was validated against an independent validation set, and compared to evaluate agreement between the two alternative approaches using Bland-Altman method. The obtained neural network for the different test patterns yields a normalized error well below 1% and the Bland-Altman plot shows a considerable correlation between the two methods. The new approach proposed herein allows a direct and fast computation for the inverse dynamics of a cyclist, opening the possibility of integrating such algorithm in a real time environment such as an embedded application.

Frontiers in Physiology, 2013

Finding an optimum for the cycling performance is not a trivial matter, since the literature show... more Finding an optimum for the cycling performance is not a trivial matter, since the literature shows the presence of many controversial aspects. In order to quantify different levels of performance, several indexes have been defined and used in many studies, reflecting variations in physiological and biomechanical factors. In particular, indexes such as Gross Efficiency (GE), Net Efficiency (NE) and Delta Efficiency (DE) have been referred to changes in metabolic efficiency (Eff Met), while the Indexes of Effectiveness (IE), defined over the complete crank revolution or over part of it, have been referred to variations in mechanical effectiveness (Eff Mech). All these indicators quantify the variations of different factors [i.e., muscle fibers type distribution, pedaling cadence, setup of the bicycle frame, muscular fatigue (MFat), environmental variables, ergogenic aids, psychological traits (Psych Tr)], which, moreover, show high mutual correlation. In the attempt of assessing cycling performance, most studies in the literature keep all these factors separated. This may bring to misleading results, leaving unanswered the question of how to improve cycling performance. This work provides an overview on the studies involving indexes and factors usually related to performance monitoring and assessment in cycling. In particular, in order to clarify all those aspects, the mutual interactions among these factors are highlighted, in view of a global performance assessment. Moreover, a proposal is presented advocating for a model-based approach that considers all factors mentioned in the survey, including the mutual interaction effects, for the definition of an objective function E representing the overall effectiveness of a training program in terms of both Eff Met and Eff Mech .

Frontiers in Computational Neuroscience, 2013

Recent studies have reported evidence that the motor system may rely on a modular organization, e... more Recent studies have reported evidence that the motor system may rely on a modular organization, even if this behavior has yet to be confirmed during motor adaptation. The aim of the present study is to investigate the modular motor control mechanisms underlying the execution of pedaling by untrained subjects in different biomechanical conditions. We use the muscle synergies framework to characterize the muscle coordination of 11 subjects pedaling under two different conditions. The first one consists of a pedaling exercise with a strategy freely chosen by the subjects (Preferred Pedaling Technique, PPT), while the second condition constrains the gesture by means of a real time visual feedback of mechanical effectiveness (Effective Pedaling Technique, EPT). Pedal forces, recorded using a pair of instrumented pedals, were used to calculate the Index of Effectiveness (IE). EMG signals were recorded from eight muscles of the dominant leg and Non-negative Matrix Factorization (NMF) was applied for the extraction of muscle synergies. All the synergy vectors, extracted cycle by cycle for each subject, were pooled across subjects and conditions and underwent a 2-dimensional Sammon's non-linear mapping. Seven representative clusters were identified on the Sammon's projection, and the corresponding eight-dimensional synergy vectors were used to reconstruct the repertoire of muscle activation for all subjects and all pedaling conditions (VAF > 0.8 for each individual muscle pattern). Only 5 out of the 7 identified modules were used by the subjects during the PPT pedaling condition, while 2 additional modules were found specific for the pedaling condition EPT. The temporal recruitment of three identified modules was highly correlated with IE. The structure of the identified modules was found similar to that extracted in other studies of human walking, partly confirming the existence of shared and task specific muscle synergies, and providing further evidence on the modularity of the motor system.

Computational and Mathematical Methods in Medicine, 2013

Two approaches to the classification of different locomotor activities performed at various speed... more Two approaches to the classification of different locomotor activities performed at various speeds are here presented and evaluated: a maximum a posteriori (MAP) Bayes’ classification scheme and a Support Vector Machine (SVM) are applied on a 2D projection of 16 features extracted from accelerometer data. The locomotor activities (level walking, stair climbing, and stair descending) were recorded by an inertial sensor placed on the shank (preferred leg), performed in a natural indoor-outdoor scenario by 10 healthy young adults (age 25–35 yrs.). From each segmented activity epoch, sixteen features were chosen in the frequency and time domain. Dimension reduction was then performed through 2D Sammon’s mapping. An Artificial Neural Network (ANN) was trained to mimic Sammon’s mapping on the whole dataset. In the Bayes’ approach, the two features were then fed to a Bayes’ classifier that incorporates an update rule, while, in the SVM scheme, the ANN was considered as the kernel function ...