This randomized within-subjects crossover-designed study evaluated intra-arterial blood pressure (BP) traits in seven healthy males (24 ± 1 years) during heavy resistance exercise (HRE) to failure (10 × 5 repetitions, 5RES) and not to failure (10 × 3 repetitions, 3RES), both at 5RM load. By combining few repetitions, avoidance of Valsalva maneuver, and restricting the duration of each contraction, we hypothesized (a) that HRE could be performed without acute excessive elevated BP; (b) a dose relationship regarding acute BP elevation following 5RES versus 3RES; and (c) both modes of HRE to induce post-exercise hypotension (PEH). BP was measured before, during, and throughout 90 minutes post-exercise. Systolic BP and mean arterial pressure decreased during 3RES (P < .001 and P < .05) and increased during 5RES (P < .01 and P < .001). The maximal individual systolic BP observed during exercise was 191 (3RES) and 212 mm Hg (5RES). Both modes of HRE induced PEH with lower systolic and mean arterial pressure (both P < .01). Documented by continuous intra-arterial BP monitoring, this study demonstrates that HRE can be performed without acute excessive elevated BP during exercise, but still induce PEH. These novel results are important, as they may pave way for future studies utilizing HRE in patients where avoidance of excessive elevated BP is important.
This study tested the effect of task-specific training of a perceptual ability for children with Developmental Coordination Disorder (DCD) compared to control children. A manual matching task (target location and pointing task) was used, which required the children to locate target pins either visually (seen target) or proprioceptively (felt target), while matching to the located target was always carried out without vision. Thirty-one children (11-12 years) were selected based on teacher statements regarding everyday motor skill performance, the DSM-IV criteria, and the Movement ABC test. Based on this, 10 children with obvious motor problems were placed in the DCD group (Trg-DCD), 9 children with no identified motor problems were placed in a training group (Trg-N), and 12 children also with no identified motor problems were placed in a control group. All the children were tested pre and post to training on a manual matching task. In the pretest, the children in the DCD group were significantly inferior to the control groups in the proprioceptive condition with both the preferred and nonpreferred hands. In the posttest, after the training periode was completed, the DCD subjects showed significant improvement in the proprioceptive condition for both preferred and nonpreferred hands. For the other groups, no significant training effects were observed across the training period. It is concluded that children in the DCD group may benefit from specific training of perceptual abilities, because they have motor control resources not exploited due to a lack of relevant experience.
Abstract Gray takes an information-processing paradigm as his departure point, invoking a comparator as part of the system. He concludes that consciousness is to be found “in” the comparator but is unable to point to how the comparison takes place. Thus, the comparator turns out not to be an entity arising out of brain research per se, but out of the logic of the paradigm. In this way, Gray both reinvents dualism and remains trapped in the language game of his own model – ending up dealing with the unknowable.
Bimanual performance depends on effective and modular bilateral communication between the two bodysides. Bilateral neural interactions between the bodysides could cause bimanual interference, and the neuromuscular system for proximal and distal muscles is differently organized, where proximal muscles have more bilateral interneurons at both cortical and spinal level compared to distal muscles. These differences might increase the potential for bimanual interference between proximal arm muscles, because of greater proportions of bilateral interneurons to proximal muscles. The purpose of the present experiment was to evaluate potential differences in bimanual interference between proximal versus distal effectors in the upper extremities. 14 participants first performed a unilateral primary motor task with dominant arm with 1) a proximal and 2) distal controlled joysticks (condition A). Performance in condition A, was compared with the same effector's performance when a bimanual interference task was performed simultaneously with the non-dominant arm (condition B). The results showed a significant bimanual interference for both the proximal and distal controlled joysticks. Most interestingly, the bimanual interference was larger for the proximal joystick compared to the distal controlled joystick. The increase in spatial accuracy error was higher for the proximal controlled joystick, compared with the distal controlled joystick. These results indicate that the proximal-distal distinction is an important organismic constraint on motor control, and especially for bilateral communication. There seem to be an undesired bilateral interference for both proximal and distal muscles. The interference is higher in the case of proximal effectors compared distal effectors, and the results seem to map the neuroanatomical and neurophysiological differences for these effectors.
The relative age effect (RAE) refers to that children born early in their year of birth show higher performance compared to children born late in the same cohort. The present study evaluated whether RAE exists within non-competitive physical education (PE) attainments, change in RAE magnitude with age, and possible gender differences. The results show a drop in PE attainment and a difference in number of high and low marks between the first and second half-year. Of the pupils who attained the highest mark, 73% were born in the first 6 months. In lower-secondary school, RAEs were larger in girls compared with boys. A possible explanation for the results is that the PE-teachers might be inspired by product-oriented criteria.
An abstract is not available for this content so a preview has been provided. Please use the Get access link above for information on how to access this content.
Entrainment is a ubiquitous property not only of interacting non-linear dynamical systems but also of human movements. In the study reported here, two premises of entrainment theory were investigated in a tapping task conducted in both interpersonal (i.e. between individuals) and intrapersonal (i.e. between effectors) conditions. Hypothesis 1 was that interacting oscillatory systems should demonstrate synchronisation, which was predicted to emerge as in-phase tapping behaviour in both inter- and intrapersonal conditions. Support for Hypothesis 1 was observed in the in-phase synchronisation of tapping in both individual bimanual trials and uni-manual and bimanual tapping in dyads. By contrast, Hypothesis 2 was that the oscillatory system with the faster initial rate would decelerate, whereas the one with the slower initial rate would accelerate, as manifest in increased self-paced tapping rates amongst participants with initially slower rates and decreased rates amongst ones who initially tapped at faster rates. However, that pattern predicted in Hypothesis 2 was not observed; on the contrary, all participants increased their tapping rates in interpersonal conditions, which occurred significantly amongst participants with the lowest preferred tapping rates. Such an outcome indicates a novel aspect of synchronised movement in humans that warrants further investigation.
This study set out to explore the suggestion that the problems experienced by 8-year-old children diagnosed as clumsy in the area of hand-eye coordination (HECP) might be attributed to a developmental lag. The performances of this group of HECP children were compared with those of groups of 5-year-old and 8-year-old controls without such deficits, when required to carry out a task involving pointing, without vision, to targets located, visually, visually/proprioceptively, or proprioceptively, the dependent variable being the distance error score from the centre of the target. The performances of the HECP children, when vision or vision/proprioception was used to locate the targets, were shown to be inferior to those of the two control groups of children thereby supporting a visual deficit hypothesis. When the targets had to be located proprioceptively, the performance of the HECP children was shown to be similar to that of the 5-year-olds, while both groups were inferior to the 8-year-olds, thereby supporting a developmental lag hypothesis in proprioceptive terms. However, when the scores for the preferred and non-preferred hands were analysed separately a marked deterioration in the performances of both the 5-year-old controls and the HECP children was observed while the 8-year-old controls were unaffected. While this finding supports a developmental lag explanation of the inferior performances of the HECP children, it was necessary to qualify such an explanation when the within-group performances using the preferred and non-preferred hands were compared. Only the HECP children, under the visual/proprioceptive or proprioceptive conditions, showed significant performance differences, in favour of the preferred hand. This finding was taken as a suggestion that the developmental lag exhibited by the HECP children might have pathological overtones possibly related to the development of the corpus callosum.
