Martine Gilles

Institut National de Recherche et de Sécurité | INRS · Working life Dept., Occupational Physiology Lab.

Optical Motion Capture Systems (OMCSs) are considered the gold standard for kinematic measurement of human movements. However, in situations such as measuring wrist kinematics during a hairdressing activity, markers can be obscured, resulting in a loss of data. Other measurement methods based on non-optical data can be considered, such as magneto-i...

This study examined whether a repetitive light assembly task could be performed according to different movement sequences identified as ways of doing (WoD), and whether the age of the participants or the work pace affected the number of WoDs selected by each participant, or the kinematic parameters for each WoDs. For two work paces, 62 right-handed...

Human movement is characterized by its variability: the same task is never performed twice in exactly the same way. This variability is believed to play a functional role in movement performance and adaptability, as well as in preventing musculoskeletal damage. This article focuses on the time-evolution of movement variability throughout a repetiti...

Current industrial production systems allow assembly of customised products which include additional elements distinguishing them from a reference model. This customisation can result in significant additional time constraints which compel workers to complete their tasks faster, which may pose problems for older workers. The objective of this labor...

Knowledge of motor variability is an essential step towards understanding a subject’s working activity. This study aims to assess within-subject and between-subject variability and the intrinsic factors that drive variability during a clip fitting task in the laboratory. Muscular activity is recorded on 6 muscles of each upper limb. Four metrics ar...

During production, companies aim to ensure optimal productivity and quality. With this in mind, workstation designers tend to assume that operators will perform tasks in a uniform manner, and tend not to include movement variability parameters in their designs. The aim of this study was to characterise movement variability during repetitive assembl...

Movement variability is an essential characteristic of human movement. It occurs in all kinds of activity including work-place tasks. However it is almost ignored in workstation design, where expected movements are highly standardized for productivity and quality considerations. Neglecting this variability may lead designers to omit parts of the fu...

Bending down to pick things up off the floor is something that we do every day. This multisegment task can be done in a considerable number of postural configurations because of the large number of degrees of freedom to be controlled when executing it. In this study where volunteers performed a repetitive bending task, multisegment kinematic analys...

The working population is getting older. Workers must adapt to changing conditions to respond to the efforts required by the tasks they have to perform. In this laboratory-based study, we investigated the capacities of motor adaptation as a function of age and work pace. Two phases were identified in the task performed: a collection phase, involvin...

Movement variability is an essential characteristic of human movement. However, despite its prevalence, it is almost completely ignored in workstation design. Neglecting this variability can lead to skip over parts of the future operator’s movements, thus bring to incomplete assessment of biomechanical risk factors. This paper starts with a focus o...

Introduction La variabilité du mouvement est une caractéristique essentielle du mouvement humain. Pourtant, elle est quasiment ignorée en conception de postes de travail. L’objectif de cette étude est donc de développer, à titre de démonstrateur de faisabilité, un humain virtuel permettant de simuler la variabilité du mouvement liée à la fatigue mu...

For several years, increasing numbers of studies have highlighted the existence of movement variability. Before that, it was neglected in movement analysis and it is still almost completely ignored in workstation design. This article reviews motor control theories and factors influencing movement execution, and indicates how intrinsic movement vari...

Standard laparoscopy is responsible for musculoskeletal problems because of surgeons anti-ergonomic positions. Robot-assisted laparoscopy seems to reduce these musculoskeletal disorders thanks to the surgeons seated position. The objective of this study is to evaluate the muscular strain and cognitive stress induced by these two techniques during r...

The authors investigated whether older adults (n = 16; mean age = 65 years) increased grip force to compensate for load force fluctuations during up and down movements more than young adults did (n = 16; mean age = 24 years) and whether older and young adults exhibited similar adaptation of grip force to alterations in friction associated with chan...

This paper presents a conceptual model for studying the contribution of each leg to sideways stability of a four-link biped. It was assumed that a linear feedback controller maintained balance with torque related to the deviation from a reference value of the angle made by the trunk with the vertical. Predictions for ground reaction forces produced...

We describe adjustments in grip force as a consequence of fluctuations in inertial load force during vertical movements of the upper limb in a patient with cerebellar degeneration. Normally grip force is adapted to load-force fluctuations, in particular to the maximum load force, which occurs early in upward movements and late in downward movements...

 In order to investigate the potential hand contribution to sideways balance, sideways pushes to the right, which subjects resisted using either the lower limbs (”hip only”) or the lower limbs assisted by the right upper limb (”hand and hip”), were delivered to the pelvis. Analysis of force and electromyogram recordings from the legs, arm and hand...

The effect of the predictability of perturbation to standing balance was evaluated in terms of the muscle activity and response dynamics of five subjects exposed to horizontal forces at the pelvis producing sideways or forward sway. Rapid (EMG onset latencies of 70–80 ms recorded from the left gluteus medius and gastrocnemius) and qualitatively dif...

This study examines the anticipatory dynamics of the center of gravity and the EMG activity of ipsi- and contralateral (to the moving leg) soleus (SOL) and tibialis anterior (TA) in flexion of the lower limb executed from different plantar support surfaces. Subjects were standing initially on a plane surface or a surface reduced to two narrow rods...