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Papers by Beatrix Vereijken
Infant Behavior and Development, 1998
One of the most frequent forms of hypoxic-ischaemic brain damage occurring before, during or afte... more One of the most frequent forms of hypoxic-ischaemic brain damage occurring before, during or after birth in preterm born children is periventricular leucomalacia (PVL). PVL can also occur in different grades (0 to V) where the level of the grade refers to the severity of the damage. The severity of the structural brain damage in the neonatal period is obtained by Magnetic Resonance Imaging (MRI). The present study, which is part of a larger project, examines the supported walking capability of preterm PVL in comparison with healthy fullterm children. The aim of the study is to examine the relationship between the degree of PVL and the supported walking capability. As the supra spinal layers, responsible for leg movements are situated closer to the ventricles than the supra spinal layers responsible for arm movements, it is to be expected that the lower limbs are more affected than the upper limbs.
Journal of experimental psychology. General, 2010
It has been suggested that human behavior in general and cognitive performance in particular emer... more It has been suggested that human behavior in general and cognitive performance in particular emerge from coordination between multiple temporal scales. In this article, we provide quantitative support for such a theory of interaction-dominant dynamics in human cognition by using wavelet-based multifractal analysis and accompanying multiplicative cascading process on the response series of 4 different cognitive tasks: simple response, word naming, choice decision, and interval estimation. Results indicated that the major portion of these response series had multiplicative interactions between temporal scales, visible as intermittent periods of large and irregular fluctuations (i.e., a multifractal structure). Comparing 2 component-dominant models of 1/f(alpha) fluctuations in cognitive performance with the multiplicative cascading process indicated that the multifractal structure could not be replicated by these component-dominant models. Furthermore, a similar multifractal structure...
European Journal of Applied Physiology, 2005
A substantial gain in strength is often observed in the early phase of resistance training. The a... more A substantial gain in strength is often observed in the early phase of resistance training. The aim of this study was to address whether improved strength in the early phase of resistance training, can be attributed to increased activation, or to intra-muscular changes of the agonist muscle during maximal isometric torque production. Fourteen male subjects trained maximal isometric dorsiflexion during
Infant Behavior and Development, 2014
The stability of a system affects how it will handle a perturbation: The system may compensate fo... more The stability of a system affects how it will handle a perturbation: The system may compensate for the perturbation or not. This study examined how 14-month-old infants-notoriously unstable walkers-and adults cope with a perturbation to walking. We attached a platform to one of participants' shoes, forcing them to walk with one elongated leg. At first, the platform shoe caused both age groups to slow down and limp, and caused infants to misstep and fall. But after a few trials, infants altered their gait to compensate for the platform shoe whereas adults did not; infants recovered symmetrical gait whereas adults continued to limp. Apparently, adult walking was stable enough to cope with the perturbation, but infants risked falling if they did not compensate. Compensation depends on the interplay of multiple factors: The availability of a compensatory response, the cost of compensation, and the stability of the system being perturbed.
European Journal of Applied Physiology, 2007
The force generated during a maximal voluntary contraction (MVC) is known to increase by resistan... more The force generated during a maximal voluntary contraction (MVC) is known to increase by resistance training. Although this increase cannot be solely attributed to changes in the muscle itself, many studies examining muscle activation at peak force failed to detect neural adaptations with resistance training. However, the activation prior to peak force can have an impact on maximal force generation.
Infant Behavior & Development, 1996
ABSTRACT We present a new footprint method for observing developmental change in spatial paramete... more ABSTRACT We present a new footprint method for observing developmental change in spatial parameters of infant walking. In contrast to more high-tech recording methods, the footprint method is reliable, quick to execute, and inexpensive. Data showed expected ...
The Quarterly Journal of Experimental Psychology Section A, 1992
This paper argues that the answer to the question, what has to be learned, needs to be establishe... more 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.
The Quarterly Journal of Experimental Psychology Section A, 1989
Seventy-five subjects, randomly assigned to one of five training conditions, were required to lea... more 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.
Physical Therapy, 2011
Valid and reliable measures of children's physical fitness are necessary for investigating the re... more Valid and reliable measures of children's physical fitness are necessary for investigating the relationship between children's physical fitness and children's health.
Perceptual and Motor Skills, 2011
The goal was to assess whether prior studies might have overestimated performance variability in ... more The goal was to assess whether prior studies might have overestimated performance variability in older adults in dual task conditions by relying on primary motor tasks that are not constant with aging. 30 younger and 31 older adults performed a bimanual tapping task at four different frequencies in isolation or concurrently with a secondary task. Results showed that performance of younger and older adults was not significantly different in performing the tapping task at all frequencies and with either secondary task, as indicated by mean tapping performance and low number of errors in the secondary tasks. Both groups showed increased variability as tapping frequency increased and with the presence of a secondary task. Tapping concurrently while reading words increased tapping variability more than tapping concurrently while naming colours. Although older participants' performances were overall more variable, no interaction effects with age were found and at the highest frequencies of tapping, younger and older participants did not differ in performance.
Parkinsonism & Related Disorders, 2008
Infant Behavior and Development, 1998
One of the most frequent forms of hypoxic-ischaemic brain damage occurring before, during or afte... more One of the most frequent forms of hypoxic-ischaemic brain damage occurring before, during or after birth in preterm born children is periventricular leucomalacia (PVL). PVL can also occur in different grades (0 to V) where the level of the grade refers to the severity of the damage. The severity of the structural brain damage in the neonatal period is obtained by Magnetic Resonance Imaging (MRI). The present study, which is part of a larger project, examines the supported walking capability of preterm PVL in comparison with healthy fullterm children. The aim of the study is to examine the relationship between the degree of PVL and the supported walking capability. As the supra spinal layers, responsible for leg movements are situated closer to the ventricles than the supra spinal layers responsible for arm movements, it is to be expected that the lower limbs are more affected than the upper limbs.
Journal of experimental psychology. General, 2010
It has been suggested that human behavior in general and cognitive performance in particular emer... more It has been suggested that human behavior in general and cognitive performance in particular emerge from coordination between multiple temporal scales. In this article, we provide quantitative support for such a theory of interaction-dominant dynamics in human cognition by using wavelet-based multifractal analysis and accompanying multiplicative cascading process on the response series of 4 different cognitive tasks: simple response, word naming, choice decision, and interval estimation. Results indicated that the major portion of these response series had multiplicative interactions between temporal scales, visible as intermittent periods of large and irregular fluctuations (i.e., a multifractal structure). Comparing 2 component-dominant models of 1/f(alpha) fluctuations in cognitive performance with the multiplicative cascading process indicated that the multifractal structure could not be replicated by these component-dominant models. Furthermore, a similar multifractal structure...
European Journal of Applied Physiology, 2005
A substantial gain in strength is often observed in the early phase of resistance training. The a... more A substantial gain in strength is often observed in the early phase of resistance training. The aim of this study was to address whether improved strength in the early phase of resistance training, can be attributed to increased activation, or to intra-muscular changes of the agonist muscle during maximal isometric torque production. Fourteen male subjects trained maximal isometric dorsiflexion during
Infant Behavior and Development, 2014
The stability of a system affects how it will handle a perturbation: The system may compensate fo... more The stability of a system affects how it will handle a perturbation: The system may compensate for the perturbation or not. This study examined how 14-month-old infants-notoriously unstable walkers-and adults cope with a perturbation to walking. We attached a platform to one of participants' shoes, forcing them to walk with one elongated leg. At first, the platform shoe caused both age groups to slow down and limp, and caused infants to misstep and fall. But after a few trials, infants altered their gait to compensate for the platform shoe whereas adults did not; infants recovered symmetrical gait whereas adults continued to limp. Apparently, adult walking was stable enough to cope with the perturbation, but infants risked falling if they did not compensate. Compensation depends on the interplay of multiple factors: The availability of a compensatory response, the cost of compensation, and the stability of the system being perturbed.
European Journal of Applied Physiology, 2007
The force generated during a maximal voluntary contraction (MVC) is known to increase by resistan... more The force generated during a maximal voluntary contraction (MVC) is known to increase by resistance training. Although this increase cannot be solely attributed to changes in the muscle itself, many studies examining muscle activation at peak force failed to detect neural adaptations with resistance training. However, the activation prior to peak force can have an impact on maximal force generation.
Infant Behavior & Development, 1996
ABSTRACT We present a new footprint method for observing developmental change in spatial paramete... more ABSTRACT We present a new footprint method for observing developmental change in spatial parameters of infant walking. In contrast to more high-tech recording methods, the footprint method is reliable, quick to execute, and inexpensive. Data showed expected ...
The Quarterly Journal of Experimental Psychology Section A, 1992
This paper argues that the answer to the question, what has to be learned, needs to be establishe... more 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.
The Quarterly Journal of Experimental Psychology Section A, 1989
Seventy-five subjects, randomly assigned to one of five training conditions, were required to lea... more 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.
Physical Therapy, 2011
Valid and reliable measures of children's physical fitness are necessary for investigating the re... more Valid and reliable measures of children's physical fitness are necessary for investigating the relationship between children's physical fitness and children's health.
Perceptual and Motor Skills, 2011
The goal was to assess whether prior studies might have overestimated performance variability in ... more The goal was to assess whether prior studies might have overestimated performance variability in older adults in dual task conditions by relying on primary motor tasks that are not constant with aging. 30 younger and 31 older adults performed a bimanual tapping task at four different frequencies in isolation or concurrently with a secondary task. Results showed that performance of younger and older adults was not significantly different in performing the tapping task at all frequencies and with either secondary task, as indicated by mean tapping performance and low number of errors in the secondary tasks. Both groups showed increased variability as tapping frequency increased and with the presence of a secondary task. Tapping concurrently while reading words increased tapping variability more than tapping concurrently while naming colours. Although older participants' performances were overall more variable, no interaction effects with age were found and at the highest frequencies of tapping, younger and older participants did not differ in performance.
Parkinsonism & Related Disorders, 2008