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Sghaier, N.

Publications and source records attributed to Sghaier, N..

2 recordsLinked to original sources

The impact of collective load transport on the individual walking

Collective handling is a collaborative strategy that involves two or more people in carrying out load transport. Different positions can be adopted, depending on the handle locations of the transported load, external constraints and the capacities of the carriers. The most adopted collective transport in our daily life is stretcher type transport. However, very little research has focused on the kinematic modifications caused by this type of transport. This research aims to evaluate and quantify the modifications of the locomotor pattern of stretcher transport. Our results highlighted a modification of walking parameters (step length, duration of the walking cycle, speed of execution, etc.), an increase in energy cost but above all a modification of the walking pattern with a reduction in joint range of motion. These results could be used to establish new recommendations for musculoskeletal disorders.

biophysics↗

Biomechanical effects of the addition of a precision constraint on a collective load carriage task

1Team lifting is a complex and collective motor task that possesses both motor and cognitive components. The purpose of this study was to investigate to what extent the biomechanics of a collective load carriage is affected when a dyad of individuals is performing a carrying task with an additional accuracy constraint. Ten dyads performed a first condition in which they collectively transported a load (CC), and a second one in which they transported the same load while maintaining a ball in a target position on its top (PC). The recovery-rate, amplitude, and period of the center-of-mass (COM) trajectory were computed for the whole system (dyad + table = PACS). We analyzed the forces and moments exerted at each joint of the upper limbs of the subjects. We observed a decrease in the overall performance of the dyads when the Precision task was added, i.e., i) the velocity and amplitude of CoMPACS decreased by 1,7% and 5,8%, respectively, ii) inter-subject variability of the Moment-Cost-Function decreased by 95% and recovery rate decreased by 19,2% during PC. A kinetic synergy analysis showed that the subjects reorganized their coordination in the PC. Our results demonstrate that adding a precision task affects the economy of collective load carriage. Notwithstanding, the joint moments at the upper-limbs are better balanced and co-vary more across the paired subjects during the precision task. Our study results may find applications in domains such as Ergonomics, Robotics-developments, and Rehabilitation.

bioengineering↗