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Comparison of ground reaction forces during the Basic Step on the Core Board platform at various levels of stability

Karczewska M., Madej A., Sadowska A., Mastalerz A., Urbanik Cz.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 4

63--70

EN

Purpose: The aim of this paper was to examine and compare the changes of ground reaction forces observed during the Basic Step on the Core Board fitness device at various levels of stability. Material and method: The study involved 10 female students. Participants stepped on and off the Core Board 10 times at 3 levels of stability. After completing a series of steps, the Core Board’s stability was modified and the participant repeated the whole series. The measurement platform to examine three components of the reaction force (horizontal in the sagittal and frontal planes, and vertical) was used. Results: The ground reaction force (GRF) observed on the Core Board, in the vertical and horizontal components is higher at all three levels of stability than on the platform without the device. Significant differences in GRF were observed in the horizontal component in the frontal plane (Fz) at all three levels of mobility as well as in impulse, measured on platforms with the device. Conclusion: The results on the Core Board training device present highest horizontal ground reaction forces in frontal plane at the highest level of Core Board mobility and this showing little medio-lateral stability and a more reactive way of movement regulation of the participants. As a consequence of the force patterns found it may be suggested that fitness training concepts should focus more possibly higher strains on the locomotor system most likely caused by changed ground reaction force patterns, an idea that has to be further analyzed with more complex measurement approaches.

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Symmetry of proprioceptive sense in female soccer players

Iwańska D., Karczewska M., Madej A., Urbanik Cz.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 2

155--163

EN

Purpose: The purpose of the study was to assess the symmetry of proprioceptive sense among female soccer players when trying to reproduce isometric knee extensions (right and left) and to analyze the impact of a given level of muscle force on proprioception. Methods: The study involved 12 soccer players aged 19.5 ± 2.65 years. Soccer players performed a control measurement of a maximum 3s (knee at the 90°) position in the joint. Subsequently, 70%, 50%, and 30% of the maximum voluntary contraction (MVC) were all calculated and then reproduced by each subject with feedback. Next, the players reproduced the predefined muscle contraction values in three sequences: A – 50%, 70%, 30%; B – 50%, 30%, 70%; C – 70%, 30%, 50% of MVC without visual control. Results: In every sequence, the participants found obtaining the value of 30% of MVC the most difficult. The value they reproduced most accurately was 70% of MVC. Both trial II and trial III demonstrated that the symmetry index SI significantly differed from values considered acceptable (SIRa). In each successive sequence the largest asymmetry occurred while reproducing the lowest values of MVC (30%) (p < 0.05). Conclusion: High level of prioprioceptive sense is important to soccer players due to the extensive overload associated with dynamics stops or changes in direction while running. Special attention should be paid to develop skills in sensing force of varying levels. It was much harder to reproduce the predefined values if there was no feedback.

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Influence of time of rest on the power decrease during exercising on the inclined plane

Witkowska I., Urbanik Cz., Karczewska M.

Acta of Bioengineering and Biomechanics

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2012

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Vol. 14, no. 3

17-22

EN

The aim of this paper is to investigate the influence of the time of rest on the change of maximal and average power as a function of time during training on an inclined plane. The values of power, developed during 7 series of 10 bounces with a 0.5 and 1 minute break, were analyzed. The research was conducted on 10 female students from the second year of master studies with a major of physical education. Taking into account the results obtained, which were compared to data from other sources, it is possible to conclude that the value of maximal power for the whole group examined during the training with a 0.5 minute break decreased by 22%, and for the training with a 1 minute break by 12%. One can assume that the training with a 0.5 minute break was more tiring, and for that reason students were not able to regenerate fully so as to bounce in the subsequent series. That is why one should say that the second method of training is more efficient for the evaluation of the maximal power of the contestant.

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The influence of a four-week training on an inclined plane on the isokinetic knee power

Staniszewski M., Mastalerz A., Urbanik Cz.

Acta of Bioengineering and Biomechanics

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2006

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Vol. 8, nr 2

51-58

EN

The aim of this study was to compare the changes in the power of knee flexors and extensors being the effect of two trainings with different structure of load. The effort depended on performing 40 repetitions in 4 series (group A) as well as 40 repetition in 1 run (group B). The power was estimated based on the value obtained under isokinetic conditions.

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The comparison of the dynamics of selected leg strokes in taekwondo WTF

Pędzich W., Mastelerz A., Urbanik Cz.

Acta of Bioengineering and Biomechanics

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2006

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Vol. 8, nr 1

83-90

EN

The aim of the study was to compare a dynamics of selected leg strokes in taekwondo WTF (Word Taekwondo Federation). Investigations were carried out in the group of 5 competitors with mastery class of taekwondo WTF. Indicators which described two maximal trials of each limb of the body for the side-kick (yop-chagi) and spinning back kick (dwit-chagi) were analyzed. The athletes executed strokes against vertically mounted force plate equipped with an appropriate absorption layer which minimized the risk of injuries. The signal of force was sampled with the frequency of 800 Hz. Signals were filtered by Bessel’s filter at a limit frequency of 75 Hz. The following indicators were analyzed: maximal and average values of stroke force, impulse of stroke, time of gaining maximal force, average velocity of increasing stroke force. The results show that taekwondo athletes recorded similar values of the strokes investigated. The differences in maximal stroke force were 6% and in average stroke force – 3% and they were also related to athlete’s weight. The results confirm athlete’s ability to use the total body mass to increase the stroke force. No significant relations were found between time of gaining maximal force and the value of stroke force. This proves that the technique of stroke, different size and kind of striking surfaces influence the value of stroke force.