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A sitting or standing position – which one exerts more loads on the musculoskeletal system of the lumbar spine? Comparative tests based on the methods of mathematical modeling

Zadoń Hanna, Nowakowska-Lipiec Katarzyna, Michnik Robert

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 1

113--120

EN

Purpose: The work aimed to assess the functioning of the musculoskeletal system within the lumbar spine in relation to everyday postures of sitting and standing. Methods: The comparative analysis was based both on experimental tests and computer simulations performed in the AnyBody Modeling System environment. Input data used to prepare models were based on the information obtained in experimental tests. The test participants were tasked with adopting two postures: 1) standing position and 2) sitting position. Kinematics measurements were performed using the Zebris ultrasonic system. During sitting position, the tests additionally involved the use of a dynamometric platform measuring reaction forces occurring between buttocks and the seat. Results: The comparative analysis included measurements of the trunk inclination angle and the pelvic inclination angle as well as results of computer simulations. The sitting posture is responsible for increased trunk inclination and a change in the position of the pelvis. In terms of the sitting position, it was possible to observe an increase in the loads affecting individual intervertebral joints of the lumbar spine by 155–184% in comparison with the standing posture (100%). Simulations revealed an increased muscle activity of the erector spinae, abdominal internal oblique muscles and abdominal external oblique muscles. Conclusions: Adopting a sitting position increases the loads on the lumbar spine and increases the activity of the erector spinae and abdominal muscles compared to the standing position, which is caused by change in the position of the pelvis and the curvature of the lumbar region.

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The level of body balance in standing position and handstand in seniors athletes practicing artistic gymnastics

Puszczałowska-Lizis Ewa, Omorczyk Jarosław

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 2

37--44

EN

The aim of the study was to compare the values of selected stability indices registered in the trials in standing with eyes open and without visual control, and in handstand in athletes practicing artistic gymnastics at the highest level of advancement. Methods: The study included 20 athletes practicing artistic gymnastics. The research tool was posturograph CQ-Stab 2P. The results obtained in individual trials were compared using Friedman repeated measures analysis of variance by ranks and then subjected to Dunn post-hoc test with Bonferroni adjustment. Results: Statistically significant differences in the values of stability indices recorded in individual samples were found. Exceptions are the results obtained in the trials with eyes open and without visual control with regard to the size of the surface area delineated by the COP ( p = 0.173) and the frequency of corrective reactions ( p = 0.464), as well as the length of the statokinesiogram path in the mediolateral direction ( p = 0.342), mean velocity of COP movement in the mediolateral direction ( p = 0.246), maximal amplitude of the COP in the mediolateral direction ( p = 0.342) and number of COP displacements in the mediolateral direction ( p = 0.246). Conclusions: In seniors, disabling visual control during free standing as well as adopting a handstand position result in deterioration of the stability indices, which is a resultant of the COP displacement in both directions as well as in the anteroposterior direction. Lack of differences in the values of stability indices in the mediolateral direction suggest that in a free standing position, seniors practicing artistic gymnastics control the movement of the center of foot pressure in the mediolateral direction and eye control is not important for the stability of the body in the frontal plane.

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Experimental studies of the influence of human standing positions on the feet-to-head transmission of vibrations

Książek M. A., Tarnowski J.

Journal of Theoretical and Applied Mechanics

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2014

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Vol. 52 nr 4

1107--1114

EN

The experiments performed on a especially built test stand, concerning the influence of human body position on the feet-to-head vibration transmission are presented. The investigations have been performed for chosen amplitudes and frequencies of source acceleration excitations coming from a vertical shaker. The big influence of standing positions of a human body on the transmitted accelerations from feet to head has been measured and analyzed. Numerical results of variability of experimental studies have been statistically elaborated and graphically presented.

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Analiza parametrów antropometrycznych sylwetki człowieka

Zawieska D.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2004

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Vol. 14

1--9

PL

Niniejszy referat zawiera opis parametrów opisujących sylwetkę badanego pacjenta w pozycji stojącej na podstawie obrazów uzyskanych z kamerki internetowej. Rejestracja sylwetki wykonana jest z widokiem z przodu i z tyłu pacjenta. Kamera jest umieszczona w urządzeniu projekcyjno-odbiorczym prążków mory. Wzbogacono w ten sposób możliwości wykorzystania systemu mory nie tylko w diagnostyce ortopedycznej i ortopedii lecz również w ergonomii. Na podstawie analizy obrazów mory i obrazów sylwetki badanych osób na wybranych stanowiskach pracy uzyskano wyniki wspomagające ocenę ergonomiczności tych miejsc pracy