Biomedical subjects

B Vereijken

Publications and source records attributed to B Vereijken.

5 recordsLinked to original sources

PubMed1998

Learning to crawl.

The effects of infants' age, body dimensions, and experience on the development of crawling was examined by observing 28 infants longitudinally, from children's first attempts at crawling until they began walking. Although most infants displayed multiple crawling postures en route to walking, development did not adhere to a strict progression of obligatory, discrete stages. In particular, 15 infants crawled on their bellies prior to crawling on hands and knees, but the other 13 infants skipped the belly-crawling period and proceeded directly to crawling on hands and knees. Duration of experience with earlier forms of crawling predicted the speed and efficiency of later, quite different forms of crawling. Most important, infants who had formerly belly crawled were more proficient crawling on hands and knees than infants who had skipped the belly-crawling period. Transfer could not be explained by differences in infants' age or body dimensions alone. Rather, experience using earlier crawling patterns may have exerted beneficial effects on hands-and-knees crawling by shoring up underlying constituents common to all forms of crawling postures.

Age Factors↗

PubMed1997

Training infant treadmill stepping: the role of individual pattern stability.

In this study, we investigated the responsiveness of a developing neuromotor system to training: When is training effective and when are the effects specific to the training condition? Eight infants, six 3-month-olds and two 7-month-olds, received month-long daily training on either a fast-running treadmill, a slow-running treadmill, or a stationary treadmill. Two additional 3-month-old infants served as controls and received no training. Results showed that training led to an increased number of steps. This improvement was inversely related to initial performance: Training had more effect on infants that initially performed unstable stepping patterns. Furthermore, training facilitated the transition from multiple stepping patterns to more alternate stepping. Again, initial pattern preferences influenced these effects of training and often remained visible throughout training. Infant's responses to training at specific speeds were less clear-cut, but some indications were found that this also depended on their initial performances as well as on the characteristics of training. In general, when initial performances corresponded to the training condition, they were strengthened. When they were different from the training condition, training effects generalized to other speeds. These results suggest that the developing neuromotor system is amenable to training whenever performance is unstable, and that training effects interact with the individual's initially preferred patterns. These results are consistent with a dynamic systems view of motor development.

Analysis of Variance↗

PubMed1992

A dynamical systems approach to skill acquisition.

This paper argues that the answer to the question, what has to be learned, needs to be established before the question, how is it learned, can be meaningfully addressed. Based on this conviction, some of the limitations of current and past research on skill acquisition are discussed. Motivated by the dynamical systems approach, the question of "what has to be learned" was tackled by setting up a non-linear mathematical model of the task (i.e. learning to make sideways movements on a ski apparatus). On the basis of this model, the phase lag between movements of the platform of the apparatus and the actions of the subject was isolated as an ensemble variable reflecting the timing of the subject in relation to the dynamics of the apparatus. This variable was subsequently used to study "how" the task was learned in a discovery learning experiment, in which predictions stemming from the model were tested and confirmed. Overall, these findings provided support for the hypothesis, formulated by Bernstein (1967), that one of the important effects of practice is learning to make use of reactive forces, thereby reducing the need for active muscular forces. In addition, the data from a previous learning experiment on the ski apparatus--the results of which had been equivocal--were reconsidered. The use of phase lag as a dependent variable provided a resolution of those findings. On the basis of the confirmatory testing of predictions stemming from the model and the clarification of findings from a previous experiment, it is argued that the dynamical systems approach put forward here provides a powerful method for pursuing issues in skill acquisition. Suggestions are made as to how this approach can be used to systematically pursue the questions that arise as a natural outcome of the experimental evidence presented here.

Adult↗

PubMed1990

In defence of discovery learning.

The present paper discusses the influence of different training methods--i.e., knowledge of results, preferred frequency, and the availability of a model--on the learning of a complex motor skill, in this case the learning of slalom ski-type movements on a ski-simulator. Results of three experiments performed on this apparatus showed that, although the training methods used influence the course of learning, none of the methods used was actually superior to discovery learning. It is suggested that discovery learning forces the learner to explore the dynamics of the system in which he or she operates, in an iterative way. Possibilities for cooperative working between prescription and discovery learning are discussed.

Feedback↗

PubMed1989

Preferred tempo in the learning of a gross cyclical action.

Seventy-five subjects, randomly assigned to one of five training conditions, were required to learn to make large-amplitude, high-tempo, fluent movements on a so-called ski-simulator over a period of four days. Subjects trained under different tempo conditions. In four of the conditions the tempo was prescribed ("preferred", high, low, or increasing), augmented feedback being provided to enable subjects to stay on "target". "Preferred" tempo was based on the weight of the subject and was derived from a regression equation based on previous empirical research. In a fifth condition, subjects trained on "discovery learning" principles, i.e. without the tempo being prescribed. The results obtained on the three parameters (amplitude, frequency, and fluency) during the daily test sessions (in which the tempo was not prescribed) formed the data for the analyses. A learning effect was apparent on all three parameters over the four-day training period. Subjects who trained under the high or the low prescribed tempos, however, were shown to produce significantly smaller amplitude movements than subjects who trained under the other three conditions. Training under the low-tempo condition was also shown to have disadvantageous effects on the parameters tempo and fluency. It was concluded that, for these kinds of action, training at a high or a low tempo--and particularly the latter--has undesirable effects. Such disadvantageous effects, however, were shown to be avoidable if training is begun with the "preferred" tempo of the subject and increased successively by 7% over days.

Adolescent↗