Is breaking it down better?

Abstract

Complex motions are generally accepted as movements which consists of at least 2 Degrees of Freedom (DoFs) actuated in a coordinated manner, which takes more than one practice session to be mastered, and that are ecologically valid (see Wulf et al. 2002 for a clear statement).

The techniques to teach and re-teach (also, (re-)learn) a complex motion are thoroughly investigated by the motor learning research community since decades and up to know. There is certain agreement on the theses of practice intensity and duration as a factor for learning. However, the content of the practice sessions is still, only, partially understood. One point which is still to be confirmed is the "Part-whole transfer" paradigm. This theory promulgates the fact that motions are rather a composition where alphabet items are skillfully combined to produce a dexterous movement and that the better the "alphabet" is known, the faster the learning will be and dexterous the result. The importance of the whole practice of a full motion remains still unknown.

Our hypotheses were that inclusion of the full motion is crucial for correctly learning a complex motion pattern. We hypothesized, also, that the way of re-composition of a motion would play a role in the performance after the training and the retention of the learned skill, as well as the transferability of its fundamentals to a new skill.

In this thesis, these questions are investigated. For this, an experiment with 16 healthy subjects has been conducted. The subjects where pseudo-randomly assigned to one of the following groups: whole visuo-haptic coordination training, anatomical visuo-haptic coordination training, anatomical visuo-haptic training and anatomical visual-only training. The importance of the haptic coordination training (i.e. practice of the whole motion together) was investigated in the first two groups, while the coordination pattern was shown only visually in the last two groups. Additionally, the way of showing the single components (anatomically or holistically) and the type of feedback (visual-only or visuo-haptic) was investigated in the different groups designed.

The results showed that the full trajectory is better learned by subjects who were shown the full motion visuo-haptically (opposed to only visually). The transfer and the consolidation of the motion pattern (also translated into a better retention) are also benefited by adding special emphasis to the single components of a motion first (Group 2). Only the training of the speed profile is benefited by more practicing the full motion visuo-haptically (i.e. group 1). All these aspects have, obviously, an impact in motivation. The groups which were more guided (i.e. visuo-haptic full motion guidance) felt less pressure, committed with less effort but got higher sense of competence and more motivation, not necessarily translating in better performance (somewhat in agreement with the Guidance Hypothesis).

The results of this study contribute to the field of motor learning bringing some more insight in the mechanisms of complex motion learning and could have a transfer to the clinical practice to improve re-learning of lost motor skills (e.g. after a stroke).