Wyniki wyszukiwania - Biblioteka Nauki

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Symmetry of lower limb loading in healthy adults during normal and abnormal stance

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Stodółka J. , Sobera M.

Acta of Bioengineering and Biomechanics

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2017

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tom Vol. 19, no. 3

93--100

EN

Purpose: The purpose of the research was twofold: (1) to describe the normal asymmetry in lower limb loading during a normal stance and during a stance with visual and vestibular disturbance relating to the lower limb dominance, (2) to assess relations of loading of both lower limbs with body weight and height (BMI) and leg functional dominance. Methods: The subjects of this study were 95 students. Settings of the two Kistler platforms were used to register the time series of the vertical component of the ground reaction force while the subject was standing (45 seconds) in a normal position and next with eyes covered with a band and head tilted back position with one leg placed on one platform and the other on the second platform. The symmetry index (SI) was used to describe the asymmetry of the left or right loading. Results: The greater loading of the left or right leg during standing was independent of the functional leg dominance. The distribution of left and right lower limb loading in both trials may suggest that a low asymmetry, less than 5%, is represented by about 30% of subjects in general. No significant correlation was found between the SI and BMI of subjects who had a normal body weight, but in the group of overweight subjects the correlation was very high (r = 0.9). Conclusion: The results show that in describing norms of asymmetry in posture control in healthy humans it is very important to compare the results to posture asymmetry in various injuries or diseases. The most important result is that the higher asymmetry of lower limb loading is associated with overweight, which implies greater risk to health of those people.

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Zmiany struktury świadczeń ekosystemów na obszarach pogórniczych. Przykład odkrywki Kazimierz w Konińskim Zagłębiu Węgla Brunatnego

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Fagiewicz K. , Sobera M.

Przegląd Górniczy

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2018

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tom T. 74, nr 12

35--43

PL

Artykuł przedstawia koncepcję świadczeń ekosystemów jako propozycję rozwiązania metodycznego zastosowanego w ocenie wpływu górnictwa węgla brunatnego na środowisko przyrodnicze i społeczno-kulturowe. Analiza zmian świadczeń ekosystemów w obszarach górniczych pozwala uzyskać syntetyczną informację o utraconych w wyniku działalności górniczej korzyściach, czerpanych z ekosystemów oraz możliwościach kreowania w procesie rekultywacji nowych geosystemów pogórniczych, o zróżnicowanym potencjale, zależnym od wizji rozwoju obszaru pogórniczego i dostosowanym do potrzeb lokalnej społeczności. Artykuł podkreśla znaczenie rekultywacji terenów pogórniczych w kształtowaniu poziomu i struktury świadczeń ekosystemów, zgodnie z priorytetami określonymi w planowaniu przestrzennym. Badaniami objęto obszar odkrywki Kazimierz zlokalizowanej w Konińskim Zagłębiu Węgla Brunatnego.

EN

This paper presents the concept of ecosystem services as a proposal of a methodical solution used in the assessment of the impact of lignite mining on natural and socio-cultural environment. Analysis of changes in ecosystem services in mining areas provides synthetic information on the benefits lost as a result of mining activities, the benefits derived from the ecosystems as well as the possibilities of creating new post-mining geosystems during the process of reclamation, with varying potentials, depending on the vision for the development of the post-mining area and adapted to the needs of the local community. The paper emphasizes the importance of the reclamation of post-mining areas in shaping the level and structure of ecosystem services in accordance with the priorities defined in the spatial planning. The research covered the open-pit area of Kazimierz, located in the Konin Lignite Basin.

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Repeatability of frequency of corrective foot pressure during balance control in children aged between 2 and 7

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Sobera M. , Siedlecka B.

Acta of Bioengineering and Biomechanics

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2010

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tom Vol. 12, no. 2

73-77

EN

The frequency of corrective signal (the centre of corrective (COC) signal), which is the decomposition of COP (centre of pressure) and estimated COM (centre of mass) time series, is one of the indicators reflecting the quality of postural control during stance. Young children, in the period of intensive development, gradually improve the quality of postural control in a daily life. The purpose of this paper was to describe the time series of corrective centre of foot pressure repeatability in young children aged between 2 and 7 during body stability in natural stance position. 272 healthy children aged between 2 and 7 were divided into 6 age groups. Two AccuSway force platforms were used (one foot of the subject was on one platform, the second foot, on the other). The COP trajectories were the basis for the calculation of the frequency stability indices in frontal and sagittal planes for the left leg and right leg separately. The COC signals were collected by the method based on the Kuczyński viscoelastic model. In order to assess the repeatability, the concordance correlation coefficient (CCC) was used between the 1st and the 2nd trials, the 2nd and the 3rd trials, and the 1st and the 3rd trials. The maturation of postural control system goes rather slowly in two youngest groups which showed the poor repeatability in COC frequency between the 2nd and the 3rd years of life. From the 4th to the 7th year of life the inter-session repeatability rapidly increases in three consecutive trials. Poor difference of frequency concordance was found between the left and right lower limbs. It is concluded that the frequency of corrective foot pressure is the reliable indicator of postural control for children aged between 4 and 7, but not for younger ones.

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The effects of sounds with low and high frequency content on postural stability

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Sobera M. , Siedlecka B. , Kuczyński M.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2006

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tom z. 26

327-332

EN

In this study, we evaluated the effect of simple sounds having different frequency on postural stability in quiet stance. Twenty-six healthy young adults (17 female and 9 male) were investigated, with an average age 19,0 ± 0,3 years. Experimental protocol included three 50s quiet standing trials, barefoot, in relaxed position, on an instrumented force plate. During the first trial the subjects were standing in silence, while during the second and third trial they were exposed to sounds with the frequency of 110 and 1000 Hz, respectively. The sounds were simple square waves at a level of 85 dB having 3 s single pulse duration and 2 s intervals. In each trial the center-of-pressure (COP) time series were recorded at a sampling rate of 20 Hz in both: the anterio-posterior (AP) and medial-lateral (ML) planes, and fed into the computer for subsequent analysis. It is conclusion that this finding lends support to different strategies observed during the exposure of our subjects to sounds having two different frequency contents, namely, normal postural strategy in the 110 Hz sound trial and automatic postural strategy in the 1 kHz sound trial.

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The influence of sounds on posture control

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Siedlecka B. , Sobera M. , Sikora A. , Drzewowska I.

Acta of Bioengineering and Biomechanics

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2015

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tom Vol. 17, no. 3

95--102

EN

Purpose: It is still not clear which parameters of sound are the most significant for body reactions and whether the way of sound reception plays a role in body control. The purpose of this study was to determine the influence of frequency, spectrum and loudness of sounds on posture control in healthy women and men. Methods: The study subjects were 29 young adults who were submitted to a 60-second standing test in the bipedal stance on the force platform (AMTI). During the tests, 3 sinusoidal sounds with various timing and 2 musical sounds (guitar and piano) of the frequency 225 Hz, 1000 Hz and 4000 Hz were applied through headphones. The centre of pressure (COP) amplitude was registered. The sway area and COP mean velocity were computed. Results: It was found that high frequency sounds contributed to a significant decrease of sway area values. No significant influence of low frequency sounds on posture control was observed. The influence of the sound spectrum (timbre) on posture control is limited; only the crescendo spectrum improves the body stability in the bipedal stance and not the music spectrum as guitar and piano. The loudness of sound, although extremely high, is not the cause of postural control changing in relation to lower loudness. No effect of gender was found in terms of body stability under different sound conditions. Conclusion. Based on the results, it can be argued that, in general, in a bipedal stance in terms of stability high sound frequency improves posture control, whereas sound spectrum and intensity show a limited impact.