Variability, performance and the ability to adapt in balance tasks
- Autores: Carla Caballero Sánchez
- Directores de la Tesis: Francisco Javier Moreno Hernández (dir. tes.)
- Lectura: En la Universidad Miguel Hernández de Elche ( España ) en 2016
- Idioma: español
- Tribunal Calificador de la Tesis: Eduardo Cervelló Gimeno (presid.), José Luis López Elvira (secret.), Isaac Estevan Torres (voc.), Ruperto Menayo Antúnez (voc.), Elizabeth Torres (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: RediUMH (pdf)
- Resumen
Postural control analysis has been one of the most studied research fields in motor control. Specifically, balance tasks have been frequently used to assess motor coordination due to de fact that maintaining balance is a usual activity and, at the same time, it is also a complex ability that involves controlling many neuromuscular components. In the literature, postural control is commonly analyzed though the analysis of the variability of the center of pressure (CoP) fluctuations in balance tasks. Variability of the human movement has been frequently interpreted as an error of the system that should be reduced as much as possible. However, current studies have outlined movement variability as a functional characteristic of the system, boosting the individual´s ability to adapt to the environment. Under this perspective, several studies have tried to find out if there is a relationship between motor variability, performance and the ability to adapt. With this purpose, motor variability has been analyzed through many measures, among which we can find traditional variables used to assess the amount of variability. Recently, new variables have been used to assess the variability structure by mathematical nonlinear tools. Despite the large number of studies on the reliability of these variables, there is still controversy about which variables better characterize postural control. The first study presented in this doctoral thesis analyses the reliability of different tools, both traditional and nonlinear, usually used to measure postural control in standing balance tasks. The results indicated that, in balance tasks, nonlinear variables show greater reliability than traditional scattering variables in the CoP analysis. In addition, mean velocity of CoP shows higher reliability values than scattering variables, showing similar values to nonlinear variables.
After knowing which variables are better to characterize postural control in balance tasks, the next step was to analyze the relationship between variability and performance. In the literature we can find controversial results about whether variability is related to greater or lower performance and how it is linked to the ability to adapt. One of the possible reasons for this controversy can be that the structure of variability depends on the different constraints from the organism, the environment and the task. In order to test this hypothesis, we outlined a study in which different task constraints were manipulated to observe their effect on motor variability and its relationship with performance. This study allowed us to verify that the relationship between the structure of CoP variability and the performance in a standing balance task is dependent on the task difficulty and the availability of biofeedback. Therefore, constraints should be taken into account to analyze motor variability and its relationship with performance and the ability to adapt.
Finally, according to current studies, it seems that variability can be related to the ability to adapt and the learning process. The third study presented in this thesis tried to check this hypothesis developing two experimental protocols in balance tasks in which a practice period was applied to promote learning. The results of both experiments showed that motor variability structure in balance tasks seems to reveal the system´s ability to learn based not only on exploration processes but also on error sensitivity.
Future studies should go in depth into the analysis of the motor variability structure as an index for predicting performance, the ability to adapt and learning, taking into account the task constraint effects and different motor tasks in order to extrapolate the results of this doctoral thesis.
