Enhanced Performance Stabilization Increases Performance Variability in a Virtual Interception Task.

Performing a motor task depends on the level of performance stabilization and movement control, and both aspects of motor behavior are related to motor learning (retention and transfer) and adaptation (predictable and unpredictable perturbations). Yet few studies have further investigated the underlying dynamics that may elicit these benefits. In this study, we investigated the effects of two levels of performance stabilization on motor performance and control while learning to intercept a virtual moving target. We randomly divided 40 participants of both sexes (Mage = 26.02 years, SD = 2.02) into a Stabilization Group (SG) and a Superstabilization Group (SSG). We considered the performance stabilized when a moving target was intercepted three times in a row and superstabilized when the same criterion was repeated six times. We analyzed outcome variables related to performance accuracy (absolute spatial error) and variability(coefficient of variation) and motor control (relative time to peak velocity-tPV% and its coefficient of variation) on both the first and last blocks of practice trials. Both groups showed comparable increases in performance accuracy from the first to the last block (p = .001, ηp2 = 1.00), but SSG presented higher variability than SG (p = .05, ηp2 = .70). Concerning motor control, both groups started the experiment with low tPV% and finished with comparably high tPV% and variability. Thus, although practicing two levels of performance stabilization led to similar performance accuracy and movement control, superstabilization resulted in higher performance variability with no loss of accuracy. Enhanced stabilization may increase the ability to adapt to environmental changes, but more research is needed to demonstrate this. These findings add to an understanding of the relationship between levels of performance stabilization and performance variability and may have implications for professional interventions (e.g. sports, rehabilitation) in considering the benefits of practice beyond performance stabilization.

Associação entre tempo de reação e de movimento em jogadores de futsal / Association between reaction and movement time in indoor soccer players

O objetivo do presente estudo foi verificar a associação entre tempo de reação (TR) simples e o tempo de movimento (TM) em jogadores de futsal jovens (13,8 ± 0,5 anos, n = 16). O TR simples foi medido no aparelho Multipsy 821, pressionando com o dedo indicador uma tecla em resposta a um sinal luminoso.O TM, giro do corpo para direita ou esquerda, foi mensurado por meio de um sistema composto por um tapete de contato, fixado ao solo, e dois pares de fotocélulas. O início e o final do movimento foram registrados pela perda de contato do pé do atleta com o tapete de contato e quando o atleta ultrapassava um par de fotocélulas duplas, respectivamente. A distância entre o tapete de contato e o primeiro par de fotocélulas foi de 1,45 m. A análise estatística não indicou correlação significativa entre as duas variáveis. Uma possível explicação para os resultados está relacionada com a estrutura dos testes utilizados e a mensuração do TR e TM em ações motoras distintas. Pode-se concluir, que o desempenho do TR simples não deve ser associado à potencialidade do atleta em realizar movimentos rápidos de giro.

The aim of the study was to verify the level of association between simple reaction time (RT) and movement time (MT) of young indoor soccer (futsal) players (13.8 ± 0.5 years, n = 16). Simple RT was measured using the Multipsy 821 apparatus with a button pressing movement as an answer to a light stimulus. MT, turning the body to the left or right, was measured by a system composed of a contact carpet, fixed on the ground, and two pairs of doubled-photocells. The beginning of the movement was registered by loss of contact with the contact carpet and the end of the movement was recorded when the player passed through the pair of doubled-photocells. The distance between the contact carpet and the first pair of photocells was 1.45 m. Statistical analysis did not indicate significant correlation for both variables. The results can be explained by differences in the structure of the used tests and by RT and MT measurement in different motor skills. Moreover, these movements have distinct demands related to body mass. To conclude, TR performance cannot be associated with the potentiality of an athlete to perform rapid body rotation movements.