VARIABILIDADE DO MOVIMENTO

Movement Variability and the Use of Nonlinear Tools: Principles to Guide Physical Therapist Practice
Harbourne, R.T.; Stergiou, N.
Physical Therapy (Mars/2009) Volume 89, Number 3: 267-282

Proposed Principles of Nonlinearity in the Acquisition and Maintenance of Motor Skill

1. An optimal amount of variability is necessary for movement to be functional and efficient; normal, efficient movement includes both deterministic and random characteristics, which can fluctuate within an optimal range.

2. Healthy motor control has characteristics of nonlinearity, including the spontaneous generation of new patterns of movement, movement possibilities that are sensitive to initial conditions, and a limited ability to precisely predict future movement based on current status.

3. If variability increases in a system without enough variability, new movement options can emerge spontaneously.

4. Because motor function is sensitive to initial conditions, each person brings a slightly different set of conditions to a motor problem, and the optimal solution to that problem may be unique to that person. Therefore, therapists cannot “prescribe” the best motor pattern or strategy that is common to all patients.

5. Input into the system can drive the system into other possibilities for movement that are not predictable. The input can come from more than one system (ie, not only motor but also sensory, cognitive, emotional, or social).

6. Measures of complexity can help predict the emergence of a new behavior or direct appropriate intervention to allow variability changes to affect function.

7. Traditional measures of variability are not equivalent to measures of complexity. For example, as the measure of standard deviation increases, the measure of approximate entropy can decrease. Measures of complexity describe the structure of variability in new ways that can help quantify subtle movement changes or characteristics.

8. Complexity is necessary for systems to adapt to changing conditions; loss of complexity means decreased ability for adaptation.

Nestes novos contextos e modelos de intervenção, o Fisioterapeuta deve estar actualizado com os conhecimentos das neurociências aplicados ao estudo do movimento humano de forma a poder analisar e compreender a interacção entre as diferentes variáveis que influenciam a (re)aprendizagem neuromotora numa pessoa única, num momento único e em condições também únicas.

Aquilo que fazemos e/ou que pedimos para os nossos pacientes realizarem não deve ser indiferente nem impessoal, mas antes responder a uma necessidade, motivação ou objectivo contextualizado dos mesmos, para que as modificações neurais (neuroplasticidade) sejam facilitadas e operacionalizadas.

"APRENDER É AQUILO QUE FICA... DEPOIS DE NOS ESQUECERMOS DE TUDO AQUILO QUE APRENDEMOS"

Raul Oliveira, Fisioterapeuta

ARTIGO DO MÊS (11/2009)

Movement Variability and the Use of Nonlinear Tools: Principles to Guide Physical Therapist Practice

Harbourne, R.T.; Stergiou, N.

Physical Therapy (Mars/2009) Volume 89, Number 3: 267-282

ABSTRACT

Fields studying movement generation, including robotics, psychology, cognitive science, and neuroscience, utilize concepts and tools related to the pervasiveness of variability in biological systems. The concepts of variability and complexity and the nonlinear tools used to measure these concepts open new vistas for physical therapist practice and research in movement dysfunction of all types. Because mounting evidence supports the necessity of variability for health and functional movement, this perspective article argues for changes in the way therapists view variability, both in theory and in action. By providing clinical examples, as well as applying existing knowledge about complex systems, the aim of this article is to create a springboard for new directions in physical therapist research and practice

"Variability in human performance and the nonlinear manner in which skills and characteristics of movement change over time reflect the complexity of the movement system.

The therapists know that a given amount of practice cannot ensure the learning of a skill in a linear manner. Our patients usually learn sporadically, progressing in a nonlinear manner over time. In addition, rates and paths of progress vary among individuals with the same diagnoses who are similar in characteristics. Motor learning progresses nonlinearly, exhibiting nonlinear learning curves depending on the task, conditions, and characteristics of the learner (Newell KM, Liu YT, Mayer-Kress G., 2001)

Nonlinear, usually used with the term “dynamics,” as in “nonlinear dynamics,” can be defined as “not in a straight line,” or as a system whose output is not proportional to its input.* Nonlinear systems are more complex than linear systems, necessitating the use of sets of equations producing unpredictable outcomes that exhibit chaotic features. In general, biological systems, including humans, are complex, nonlinear systems with inherent variability in all healthy organisms (Walleczek J., 2000)

As (re) aprendizagens neuromotoras que os Fisioterapeutas procuram facilitar, orientar, induzir nos seus pacientes, no contexto da Reeducação Funcional, são momentos únicos, individuais, complexos, que estão dependentes de uma série de variáveis intrinsecas ao sujeito, de variáveis relacionadas com o meio envolvente e ainda com a interacção paciente/terapeuta.

Neste modelo de intervenção, que envolve a pessoa toda nas suas várias dimensões, condicionantes ou constrangimentos bem como na sua interacção com o FT, o tratamento não é SUSCEPTIVEL DE SER PRESCRITO, nem SE DEVE REALIZAR SEMPRE AS MESMAS ACTIVIDADES/TAREFAS

Raul Oliveira, Fisioterapeuta