17th Annual ECSS-Congress, Bruges 2012

Abstract details

Abstract-ID: 646
Session: [MO-BN18] Muscle Fatigue
Lecture room: Forum
Date & time: 04.07.2014 / 15:00 - 16:00
Title of the paper: Strategies of control and inherent characteristics of the individuals in balance tasks.
Authors: Caballero, C., Barbado, D., Urbán, T., Moreno, F.J.
Institution: Miguel Hernández University
Department: Department of Psychology and Health
Country: Spain
Abstract text Introduction Some studies have revealed that the structure of movement variability changes as task constraints increase or as participants adopt a new strategy of control (Van Order, Kloos & Wallot, 2011). Nevertheless, previous works have suggested that human variability also reveals inherent characteristics of the individual (Riley & Turvey, 2002). Previous works in balance tasks have identified that some variability characteristics of COP remain constant between trials while others change under the same task conditions (Caballero, Barbado, Moreno, 2013). In this study we have manipulated different task constraints in order to know which variability characteristics of COP change according to the motor control requirements and which ones remain constant revealing inherent characteristics of the individual. Methods Fourteen volunteers took part in this study (Age 29.5 ± 7.44 years; Height 1.73 ± 0.1 m; Mass 72.07 ± 8.94 Kg). Participants were asked to stand still (70s) on a stable surface and under three unstable situations increasing the difficulty in each situation. Each situation was performed twice, with and without visual feedback. COP excursion was collected from a force platform. Balance performance was assessed by bivariate variable error (BVE) and mean velocity of magnitude (VMeanM). Dynamics of COP displacement and velocity were measured through Fuzzy Entropy (FE), Permutation Entropy (PE) and Detrended Fluctuation Analysis (DFA). Repeated measures ANOVAs were used to analyse the differences between balance difficulty and the effect of visual feedback. Results COP excursion, expressed in BVE and VmeanM values, increased according to the difficulty of the unstable situation. Regarding the structure of COP, FE and PE increased when the difficulty increased, both in displacement and velocity signal, although in the second signal to a lesser extent. DFA didn’t show changes depending on this constraint. On the other hand, PE, FE and DFA velocity were constant despite the effect of visual feedback, whereas FE increased and DFA decreased with visual feedback in COP displacement. Discussion The manipulation of task constraints produces changes both in excursion and structure of COP. However, the structure of COP velocity seems to be less affected by tasks constraints. It could reflect that the COP displacement reflects the strategy of control under different constraints, while the velocity, which indicates the ratio of the position changes, seems to represent inherent characteristics of the individual motor variability. Reference Caballero, C., Barbado, D., & Moreno, F. J. (2013). Revista Andaluza de Medicina del Deporte, 6(3), 101-107. Riley, M. A., & Turvey, M. T. (2002). Journal of motor behavior, 34(2), 99-125. Van Orden, G. C., Kloos, H., & Wallot, S. (2011). Philosophy of complex systems. Handbook of the philosophy of science, 10. Contact ccaballero@umh.es
Topic: Biomechanics
Keyword I: constraints
Keyword II: structure COP
Keyword III: balance tasks