Brice ISABLEU | Aix-Marseille University (original) (raw)

Papers by Brice ISABLEU

1,2 Clint Hansen, 1 Brice Isableu, 2Philippe Gorce ,2Nasser Rezzoug and 3 Gentiane Venture 1 Univ... more 1,2 Clint Hansen, 1 Brice Isableu, 2Philippe Gorce ,2Nasser Rezzoug and 3 Gentiane Venture 1 Univ. Paris-Sud. URCIAMS EA4532– Motor Control & Perception team, Orsay F-91405, France 2Univ du Sud. Toulon Var, HandiBio, EA 4322, La Garde F-83957 ; 3 Tokyo University of Agriculture and Technology. Department of Mechanical Systems Engineering – GVLab, Tokyo, Japan 1 Clint Hansen; email: Clint.Hansen@u-psud.fr

Computer Animation and Virtual Worlds, 2021

Postural interaction is of major importance during job interviews. While several prototypes enabl... more Postural interaction is of major importance during job interviews. While several prototypes enable users to rehearse for public speaking tasks and job interviews, few of these prototypes support subtle bodily interactions between the user and a vir

Human movement science, Jan 14, 2017

We examined if experts and novices show different utilization of the torque components impulses d... more We examined if experts and novices show different utilization of the torque components impulses during dart throwing. Participants threw darts continuously at a dartboard aiming for the centre (target bull's eye). The upper-limb joint torque impulses were obtained through inverse dynamics with anthropometric and motion capture data as input. Depending on the joint degree of freedom (DOF) and movement phase (acceleration and follow-through), three main strategies of net torque (NET) impulse generation through joint muscle (MUS) and interaction (INT) torque impulses were highlighted. Firstly, our results showed that the elbow flexion-extension DOF leads the movement according to the joint leading hypothesis. Then, considering the acceleration phase, the analysis revealed differences in torque impulse decomposition between expert and novices. For the glenohumeral (GH) joint abduction-adduction and for wrist flexion, the INT torque impulse contributed positively to NET joint torque ...

Frontiers in Psychology, 2018

Proceedings of the 2017 ACM/IEEE International Conference on Human-Robot Interaction, 2017

Imitation is of major importance during social interactions, would it be between humans or betwee... more Imitation is of major importance during social interactions, would it be between humans or between a human and a robot. This is even more true when considering users with special needs. In this paper, we describe an experimental imitation task protocol using a robot Nao that we designed to assess whether sensory profiles of children with Autistic Spectrum Disorder (ASD) influence their capabilities to imitate or to initiate gestures that are going to be imitated. We based our work on the hypothesis that children with an overreliance on proprioceptive cues and hyporeactivity to visual cues have a greater difficulty imitating and improve their skills more slowly than children with an overreliance on visual cues and hyporeactivity to proprioceptive cues. Twelve children and teenagers with ASD participated in seven imitation sessions over eight weeks. As expected, we observed that children with an overreliance on proprioceptive cues and hyporeactivity to visual cues had more difficulties imitating the robot than the other children. Moreover, the repeated sessions revealed to have positive effects on social behaviors displayed by all children (gaze to the partner, imitations) toward a human partner after the sessions with the robot. We conclude on the possible impacts of such results on the design of social human-robot interactions for users with ASD.

Human movement science, Jan 6, 2016

The purpose of the present study was to evaluate the impact of four mood conditions (control, pos... more The purpose of the present study was to evaluate the impact of four mood conditions (control, positive, negative, aroused) on movement expressivity during a fitness task. Motion capture data from twenty individuals were recorded as they performed a predefined motion sequence. Moods were elicited using task-specific scenarii to keep a valid context. Movement qualities inspired by Effort-Shape framework (Laban & Ullmann, 1971) were computed (i.e., Impulsiveness, Energy, Directness, Jerkiness and Expansiveness). A reduced number of computed features from each movement quality was selected via Principal Component Analyses. Analyses of variance and Generalized Linear Mixed Models were used to identify movement characteristics discriminating the four mood conditions. The aroused mood condition was strongly associated with increased mean Energy compared to the three other conditions. The positive and negative mood conditions showed more subtle differences interpreted as a result of their m...

Journal of Applied Biomechanics, 2016

For the dominant limb, a velocity-dependent change in rotational axes during the kinesthetic cont... more For the dominant limb, a velocity-dependent change in rotational axes during the kinesthetic control of unconstrained 3D arm rotations was reported, and thus the question arises if this can be reproduced for the nondominant arm. The rotation axes considered are the axes of minimum inertia (e3), the shoulder–center of mass axis (SH-CM), and the shoulder–elbow axis (SH-EL). The objective of this study was to examine whether the minimum inertia axis would constrain internal–external rotations of the shoulder at fast velocity. Participants performed cyclic rotations of their arms in 2 sensory conditions and at 2 velocities. The elbow configurations were either set to 90° or 140° to yield a constant separation between e3, SH-CM, and SH-EL. Our results showed that the limb’s rotational axis coincide with the SH-EL axis across velocity conditions, although higher variability was seen at higher velocity. This was true for both the dominant and the nondominant arm. Together, the results show...

ACM Transactions on Applied Perception, 2015

Virtual sport coaches guide users through their physical activity and provide motivational suppor... more Virtual sport coaches guide users through their physical activity and provide motivational support. Users’ motivation can rapidly decay if the movements of the virtual coach are too stereotyped. Kinematic patterns generated while performing a predefined fitness movement can elicit and help to prolong users’ interaction and interest in training. Human body kinematics has been shown to convey various social attributes such as gender, identity, and acted emotions. To date, no study provides information regarding how spontaneous emotions and personality traits together are perceived from full-body movements. In this article, we study how people make reliable inferences regarding spontaneous emotional dimensions and personality traits of human coaches from kinematic patterns they produced when performing a fitness sequence. Movements were presented to participants via a virtual mannequin to isolate the influence of kinematics on perception. Kinematic patterns of biological movement were ...

2013 Humaine Association Conference on Affective Computing and Intelligent Interaction, 2013

Neuroscience Letters, 2009

We examined to which extent proprioceptive information involved in the perception of subjective v... more We examined to which extent proprioceptive information involved in the perception of subjective vertical corresponded to mechanical mass-based axes of the body. Blindfolded subjects (n = 14) estimated their subjective vertical in conditions of deviation of the centre of mass (CM) of (1) the head-trunk unit or (2) the head segment alone. Verticality estimates (provided in a haptic modality) were significantly altered by the deviation of the head-trunk CM (by either 4 • or 7 •), indicating that the subjects used mass-based proprioceptive information stemming from the trunk. Modifying the perception of body orientation by shifting the trunk CM sideways while keeping the body vertical, deviates the subjective vertical towards the opposite side in a similar way to the so-called 'E-effect'. The induced deviations of head CM (9.33 •) did not affect the subjective vertical, suggesting that when the balance of the body is not threatened, proprioceptive or vestibular information is prioritized to estimate gravitational direction.

Experimental Brain Research, 2011

The present experiment was designed to assess the effect of active (deliberate) maintenance of a ... more The present experiment was designed to assess the effect of active (deliberate) maintenance of a small forward (FL) or backward body lean (BL) (about 2°ankle flexion) with respect to the spontaneous direction of balance (or neutral posture, N) on postural balance. We questioned whether BL and FL stances, which impose a volitional proprioceptive control of the body-on-support angle, could efficiently reduce mediolateral displacements of the centre of pressure (CoP) induced by the visual motion of a room and darkness. Subjects (n = 15) were asked to stand upright quietly feet together while confronted to a large visual scene rolling to 10°on either side in peripheral vision (and surrounding vertical visual references in central vision) at 0.05 Hz. CoP displacements were recorded using a force platform. Analysis of medio-lateral CoP root-mean square showed that the effect of the moving room depends on the subject's postural stability performance in the eyes open N stance condition. Two significant postural behaviours emerged. (1) The most stable subjects (G1) were not affected by the conditions of altered vision, but swayed more in BL stance than in the N stance. (2) The unstable subjects (G2) exhibited (i) larger CoP displacements in altered visual conditions and a greater coupling of the CoP with the motion of the visual scene, (ii) enhanced visual dependency with postural leaning, and (iii) decreased CoP displacements when leaning forward in the eyes open motionless scene. Interestingly, the visual quotient positively correlated with the proprioceptive quotient, indicating that the more the subjects relied heavily on the visual frame of reference (FOR) the more they were influenced by body leaning. This result suggested hence a lesser ability to use efficiently bodyground proprioceptive cues. On the whole, the present findings indicate that body leaning could provide a useful mean to assess the subject's ability to use body-ground proprioceptive cues not only to improve postural stability during eyes opening (especially during forward leaning), but also as a mean to disclose subjects' visual dependency and their associated difficulties to shift from visual to proprioceptive-based FOR.

Frontiers in Human Neuroscience

We compared postural control of expert gymnasts (G) to that of non-gymnasts (NG) during bipedal c... more We compared postural control of expert gymnasts (G) to that of non-gymnasts (NG) during bipedal closed-eyes quiet standing using conventional and nonlinear dynamical measures of center of foot pressure (COP) trajectories. Earlier findings based on COP classical variables showed that gymnasts exhibited a better control of postural balance but only in demanding stances. We examined whether the effect of expertise in Gymnastic can be uncovered in less demanding stances, from the analysis of the dynamic patterns of COP trajectories. Three dependent variables were computed to describe the subject's postural behavior: the variability of COP displacements (A CoP), the variability of the COP velocities (V CoP) and the sample entropy of COP (SEn CoP) to quantify COP regularity (i.e., predictability). Conventional analysis of COP trajectories showed that NG and G exhibited similar amount and control of postural sway, as indicated by similar A CoP and V CoP values observed in NG and G, respectively. These results suggest that the specialized balance training received by G may not transfer to less challenging balance conditions such as the bipedal eyes-closed stance condition used in the present experiment. Interestingly, nonlinear dynamical analysis of COP trajectories regarding COP regularity showed that G exhibited more irregular COP fluctuations relative to NG, as indicated by the higher SEn CoP values observed for the G than for the NG. The present results showed that a finer-grained analysis of the dynamic patterns of the COP displacements is required to uncover an effect of gymnastic expertise on postural control in nondemanding postural stance. The present findings shed light on the surplus value in the nonlinear dynamical analysis of COP trajectories to gain further insight into the mechanisms involved in the control of bipedal posture.

Journal of Motor Behavior

The authors asked how sport expertise modulates visual field dependence and sensory reweighting f... more The authors asked how sport expertise modulates visual field dependence and sensory reweighting for controlling posture. Experienced soccer athletes, ballet dancers, and nonathletes performed (a) a Rod and Frame test and (b) a 100-s bipedal stance task during which vision and proprioception were successively or concurrently disrupted in 20-s blocks. Postural adaptation was assessed in the mean center of pressure displacement, root mean square of center of pressure velocity and ankle muscles integrated electromyography activity. Soccer athletes were more field dependent than were nonathletes. During standing, dancers were more destabilized by vibration and required more time to reweigh sensory information compared with the other 2 groups. These findings reveal a sport skill-specific bias in the reweighing of sensory inputs for spatial orientation and postural control.

PloS one, 2017

By proposing efficient methods for estimating Body Segment Inertial Parameters' (BSIP) estima... more By proposing efficient methods for estimating Body Segment Inertial Parameters' (BSIP) estimation and validating them with a force plate, it is possible to improve the inverse dynamic computations that are necessary in multiple research areas. Until today a variety of studies have been conducted to improve BSIP estimation but to our knowledge a real validation has never been completely successful. In this paper, we propose a validation method using both kinematic and kinetic parameters (contact forces) gathered from optical motion capture system and a force plate respectively. To compare BSIPs, we used the measured contact forces (Force plate) as the ground truth, and reconstructed the displacements of the Center of Pressure (COP) using inverse dynamics from two different estimation techniques. Only minor differences were seen when comparing the estimated segment masses. Their influence on the COP computation however is large and the results show very distinguishable patterns of...

Sports biomechanics, Jan 28, 2017

The purpose of this study was to evaluate the role of rotation axes during a tennis serve. A moti... more The purpose of this study was to evaluate the role of rotation axes during a tennis serve. A motion capture system was used to evaluate the contribution of the potential axes of rotation (minimum inertia axis, shoulder-centre of mass axis and the shoulder-elbow axis) during the four discrete tennis serve phases (loading, cocking, acceleration and follow through). Ten ranked athletes (International Tennis Number 1-3) repeatedly performed a flat service aiming at a target on the other side of the net. The four serve phases are distinct and thus, each movement phase seems to be organised around specific rotation axes. The results showed that the limbs' rotational axis does not necessarily coincide with the minimum inertia axis across the cocking phase of the tennis serve. Even though individual serving strategies were exposed, all participants showed an effect due to the cocking phase and changed the rotation axis during the task. Taken together, the results showed that despite int...

Frontiers in Human Neuroscience, 2017

The present study aimed to compare various entropy measures to assess the dynamics and complexity... more The present study aimed to compare various entropy measures to assess the dynamics and complexity of center of pressure (COP) displacements. Perturbing balance tests are often used in healthy subjects to imitate either pathological conditions or to test the sensitivity of postural analysis techniques. Eleven healthy adult subjects were asked to stand in normal stance in three experimental conditions while the visuo-kinesthetic input was altered. COP displacement was recorded using a force plate. Three entropy measures [Sample Entropy (SE), Multi-Scale Entropy (MSE), and Multivariate Multi Scale Entropy (MMSE)] describing COP regularity at different scales were compared to traditional measures of COP variability. The analyses of the COP trajectories revealed that suppression of vision produced minor changes in COP displacement and in the COP characteristics. The comparison with the reference analysis showed that the entropy measures analysis techniques are more sensitive in the incremented time series compared to the classical parameters and entropy measures of original time series. Non-linear methods appear to be an additional valuable tool for analysis of the dynamics of posture especially when applied on incremental time series.

Autism - Paradigms, Recent Research and Clinical Applications, 2017

In this paper, we presented a method to define individual profiles in order to develop a new pers... more In this paper, we presented a method to define individual profiles in order to develop a new personalized robot-based social interaction for individual with Autistic Spectrum Disorder (ASD) with the hypothesis that hyporeactivity to visual motion and an overreliance on proprioceptive information would be linked to difficulties in integrating social cues and in engaging in successful interactions. We succeed to form three groups among our 19 participants (children, teenagers and adults with ASD), describing each participant's response to visual and proprioceptive inputs. We conducted a first In-doc controls experiment to present the robot Nao as a social companion, and to avoid fear or stress towards the robot in future experiment. No direct link between the behavior of the participants towards the robot and their proprioceptive and visual profiles was observed. Still, we found encouraging results going in the direction of our hypothesis. In addition, almost all of our participants showed great interest to Nao. Defining such individual profiles prior to social interactions with a robot could provide promising strategies for designing successful and adapted Human-Robot Interaction (HRI) for individuals with ASD.