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The influence of sounds on posture control

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

Acta of Bioengineering and Biomechanics

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2015

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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.

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

Sobera M., Siedlecka B.

Acta of Bioengineering and Biomechanics

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2010

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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

Sobera M., Siedlecka B., Kuczyński M.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2006

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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.