The aim of this study was to investigate the motor control strategies adopted when performing two jumping tasks with different task demands when analysed at an individual and group level. Twenty-two healthy individuals performed two jumping tasks: jumping without the use of an arm swing (CMJnas) and jumping starting in a plantar flexed position with the use of an arm swing (PF). Principal component analysis (PCA) was performed using hip, knee and ankle joint moment data on individual (PCAi) and group data (PCAc). The results demonstrate that a greater number of PCs are required to explain the majority of variance within the dataset in the PF condition at both an individual and group level, compared to CMJnas condition. Although common control strategies were observed between the two jumping conditions, differences in the organisation of the movement (PC loading coefficients) were observed. Results from the group analysis did not completely reflect the individual strategies used to perform each jumping task and highlight the value in performing individual analysis to determine emergent control strategies.
- MeSH
- biomechanika MeSH
- kolenní kloub * MeSH
- koleno * MeSH
- lidé MeSH
- pohyb MeSH
- rozsah kloubních pohybů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The purpose of this study was to examine the motor control strategies employed to control the degrees of freedom when performing a lower limb task with constraints applied at the hip, knee, and ankle. Thirty-five individuals performed vertical jumping tasks: hip flexed, no knee bend, and plantar flexed. Joint moment data from the hip, knee, and ankle were analyzed using principal component analysis (PCA). In all PCA performed, a minimum of two and maximum of six principal components (PC) were required to describe the movements. Similar reductions in dimensionality were observed in the hip flexed and no knee bend conditions (3PCs), compared to the plantar flexed condition (5PCs). A proximal to distal reduction in variability was observed for the hip flexed and no knee bend conditions but not for the plantar flexed condition. Collectively, the results suggest a reduction in the dimensionality of the movement occurs despite the constraints imposed within each condition and would suggest that dimensionality reduction and motor control strategies are a function of the task demands.
Postural control and breathing are mechanically and neuromuscularly interdependent. Both systems- of spinal stability and respiration- involve the diaphragm, transversus abdominis, intercostal muscles, internal oblique muscles and pelvic floor muscles. The aim of the study was to evaluate the effect of exercises activating deep stabilizer muscles on postural control and quality of breathing movements. Eighteen volunteers (25,7 ± 3,5) were recruited from the general population. All the subjects implemented an exercise program activating deep muscles. Head, pelvic and trunk positions in the sagittal and frontal planes were assessed with the photogrammetric method. Breathing movements were estimated with the respiratory inductive plethysmography. The results indicate that the use of deep muscle training contributed to a significant change in the position of the body in the sagittal plane (p = 0.008) and the increase in the amplitude of breathing (p = 0.001).
- MeSH
- bránice fyziologie MeSH
- břišní svaly fyziologie MeSH
- cvičení fyziologie MeSH
- dospělí MeSH
- dýchání * MeSH
- elektromyografie MeSH
- lidé MeSH
- mladý dospělý MeSH
- pohyb fyziologie MeSH
- postura těla fyziologie MeSH
- trup fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The authors investigate the ways in which varied postural responses to translating platform perturbations are associated with the variables of strength and power. Twenty-four physically active and 27 sedentary young adults were exposed to a set of postural perturbations at varied velocities (10 and 20 cm/s) and the respective accelerations (6.4 and 6.9 m/s2), constant distance (6 cm), and 4 directions of platform motion (forward, backward, left-lateral, and right-lateral). They also performed maximum voluntary isometric contraction (MVC) and chair rising/chair jumping tests. The analysis of variance revealed significant interaction effect for peak center of pressure displacement, direction by velocity: F3,129= 24.43, p = .002; and direction by acceleration: F3,129= 34.18, p = .001. There were no significant correlations between peak center of pressure displacements and peak force and peak rate of force development measured during MVC in either standing (r = .27-57) or sitting positions (r = .12-51) and peak power during chair jumping (r = .47-.59) in all participants. As such, only a small proportion of variance was explained (9-39%, 3-23%, and 23-41%, respectively). In conclusion, interaction effects indicate that the composition of stimuli strongly influences compensatory responses and this effect is more pronounced in sedentary than in physically active young adults. Nevertheless, the dynamic balance is not associated with muscle strength and power in either group.
- MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- postura těla fyziologie MeSH
- posturální rovnováha fyziologie MeSH
- sedavý životní styl MeSH
- svalová síla fyziologie MeSH
- tělesná výkonnost MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Although literature surrounding handedness and cerebellar asymmetry is limited, many researchers have suggested that a relationship exists (e.g., A. A. Beaton, 2003; L. Jäncke, K. Specht, S. Mirzazade, & M. Peters, 1999; I. C. McManus & K. M. Cornish, 1997; M. Peters, 1995; P. J. Snyder, R. M. Bilder, H. Wu, B. Bogerts, & J. A. Lieberman, 1995). For example, J. Tichy and J. Belacek ( 2008 , 2009 ) identified a link between cerebellar dominance and hand preference. The authors aimed to assess the relationship between cerebellar dominance and handedness, in 8-10-year-olds (N = 157 right-handers) as assessed with hand performance tests. Articular joint passivity in the wrist and performance differences between the hands were used as a means of assessing cerebellar dominance, where a link to skilled hand performance tests was revealed. Specifically, significant correlations between articular joint passivity and all measurements of handedness (p < .001) were observed. Greater hypotonia was seen in the left wrist of 95% of right-handers. This result supports the assumption that the preferred and nonpreferred hand could be controlled by the cerebellum in a different ways.
- MeSH
- dítě MeSH
- funkční lateralita fyziologie MeSH
- lidé MeSH
- motorické dovednosti fyziologie MeSH
- mozeček fyziologie MeSH
- ruka fyziologie MeSH
- svalová hypotonie patofyziologie MeSH
- zápěstní kloub patofyziologie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
