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The Effect of Task-Oriented Sensorimotor Exercise on Visual Feedback Control of Body Position and Body Balance

100%
Zemková E., Hamar D.
Human Movement
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2010
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vol. 11
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issue 2
119-123
EN
Purpose. The study evaluates the effect of task-oriented sensorimotor exercise on visual feedback control of body position and parameters of static and dynamic balance. Basic procedures. A group of 20 PE students (aged 21.5 ± 1.6 years, height 178.2 ± 10.6 cm, and weight 74.5 ± 11.8 kg) performed task-oriented sensorimotor exercise (20 sets of 60 stimuli with 2 min rest in-between). They had to hit the target randomly appearing in one of the corners of the screen by horizontal shifting of COM in appropriate direction. Response time, distance, and velocity of COP trajectory were registered during standing on unstable spring-supported platform equipped with PC system for feedback monitoring of COM movement. Postural stability was evaluated under both static and dynamic conditions (wobble board). The COP velocity was registered at 100 Hz by means of the posturography system FiTRO Sway Check based on dynamometric platform. Main findings. Mean response time significantly (p ≤ 0.01) decreased from 3100.5 ± 1019.8 ms to 1745.8 ± 584.5 ms. Substantial share of the improvements took place during initial 6 trials. At the same time also mean distance of COP movement significantly (p ≤ 0.05) decreased from 0.767 ± 0.340 m to 0.492 ± 0.190 m within initial 12 trials and then slightly increased up to 0.591 ± 0.247 m. On the other hand, mean COP velocity significantly (p ≤ 0.05) increased from 0.285 ± 0.142 m/s to 0.395 ± 0.182 m/s. However, there were no changes in the COP velocity registered in static (from 12.4 ± 1.8 mm/s to 11.9 ± 1.5 mm/s) and dynamic conditions (from 108.0 ± 22.3 mm/s to 101.3 ± 18.1 mm/s). Conclusions. Task-oriented sensorimotor exercise acutely enhances visual feedback control of body position but not static and dynamic balance.
2
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Jumping Impairs Visual Feedback Control of Body Position

100%
Zemková E., Hamar D.
Human Movement
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2011
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vol. 12
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issue 3
248-253
EN
Purpose. The aim of this study was to evaluate the effects of maximal rebound jumping on sensorimotor tasks that required visual feedback control in positioning the body. Methods. A group of 14 university students (age 23.7 ± 2.6 y, height 178.6 ± 9.2 cm, and weight 70.6 ± 11.4 kg) had to hit a target that randomly appeared on one side of a screen by horizontally shifting their centre of mass (COM) in the appropriate direction prior to (as a baseline) and after six 60-second maximal jump exercises. Each response test consisted of 60 targets. The time, distance, and the velocity of the centre of pressure (COP) trajectory between the stimulus's appearance and its hit, by visually-guiding the COM movement on the screen, were registered by means of a FiTRO Sway Check system using a dynamometric platform. During the sets of jumps, the power of the concentric phase of take off was registered using a FiTRO Jumper recorder. Results. Results found that after each set of jumping (of around 110 jumps per set), mean response time significantly (p ≤ 0.05) increased from an initial value of 1616 ± 506 ms to 1825 ± 562 ms till the 4th set, with no further increase towards the 6th set. Similarly, the mean distance of COP covered during the response time increased significantly (p ≤ 0.05) from a pre-exercise value of 0.449 ± 0.298 m to 0.550 ± 0.295 m after the 4th set which then plateaued towards the 6th set. However, no significant changes in mean COP velocity were detected. Conclusion. Rebound jumping negatively affected the visual feedback control in positioning the body. However, after the proprioceptive functions deteriorated to a certain level, there was no further impairment on sensorimotor parameters.
3
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Postural Sway Response to Rebound Jumps of Different Duration

81%
Zemková E., Kyselovičová O., Hamar D.
Human Movement
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2010
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vol. 11
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issue 2
153-156
EN
Purpose. The study compares the sway variables after continuous CMJs eliciting different level of proprioceptive stimulation determined by percentage of max height of the jump. Basic procedures. A group of 11 aerobic dancers performed in random order repeated jumps with maximal effort until the jump height dropped to 75%, 50%, and 25% of previously established max jump achieved in non-fatigued conditions. The height of CMJs was calculated from flight times registered by FiTRO Jumper. Thirty seconds prior to and two minutes after exercises the COP velocity was registered at 100 Hz by means of posturography system FiTRO Sway Check based on dynamometric platform. Main findings. Results showed that max height of the jump (MJ) decreased from 27.7 ± 2.8 cm to 20.1 ± 2.6 cm when subjects matched 75% of 1MJ, to 13.8 ± 1.6 cm at 50% of 1MJ, and to 6.9 ± 0.8 cm at 25% of 1MJ. The COP velocity was significantly (p ≤ 0.01) higher after jumps dropped to 75% of 1MJ as compared to baseline (from 9.2 ± 1.6 mm/s to 14.5 ± 2.4 mm/s). Its further significant (p ≤ 0.05) increase was observed after jumps dropped to 50% of 1MJ (to 19.6 ± 2.6 mm/s). However, there was only slight increase in COP velocity after jumps dropped to 25% of 1MJ (to 21.4 ± 3.2 mm/s). Conclusions. Taking into account a gradual increase in sway velocity after jumps matched 75% and 50% of 1MJ and its no further increase after jumps matched 25% of 1MJ, it may be assumed that post-exercise balance impairment is not linearly related to the level of proprioceptive stimulation.
4
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Power production during bench press with different ranges of motion on stable and unstable surfaces

71%
Zemková E., Jeleň M., Ollé G., Vilman T., Hamar D.
Human Movement
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2013
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vol. 14
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issue 4
328-333
EN
Purpose. The study compared power during concentric-only and countermovement (CM) bench press with different ranges of motion (ROM) on a stable and unstable surface. Methods. A group of 22 fit men performed three repetitions of 1) full ROM concentric-only bench press, 2) full ROM CM bench press, 3) half ROM concentric-only bench press, and 4) half ROM CM bench press, on a bench (stable) and Swiss ball (unstable) at 60% 1RM. The FiTRO Dyne Premium system was used to monitor force and velocity and calculate power. Mean values of power during the acceleration and the entire concentric phases were analyzed. Results. No significant differences were found in mean power during concentric-only bench press on the bench and Swiss ball performed at half ROM and full ROM. Likewise, mean power during the concentric phase of half-range CM bench press on the bench and Swiss ball did not differ significantly. However, power values during full-range CM bench press were significantly higher on the bench than on Swiss ball. These differences were even more pronounced for mean power during the acceleration phase of full-range CM bench press on the bench compared with the Swiss ball. Contrary to this, these values did not differ significantly when the barbell was lifted during half ROM bench press on the bench and Swiss ball. Conclusions. Power was significantly lower during full-range CM bench press on the Swiss ball than on the bench, however, values did not differ significantly during stable and unstable half-range CM bench press.
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