Biomechanical influences on head posture and the respiratory movements of the chest.

PURPOSE: The head represents 6% of total body weight, therefore it can significantly affect the biomechanics of human posture control, movements and activities. When set out of vertical body axis, head position interferes with the work of the other links in the kinematic chain. The aim of our study was to evaluate the effect of head posture on the breathing activities of the chest. MATERIAL AND METHODS: The research was conducted on a group of 65 patients (51 years ± 9.8 years), including 48 women and 17 men. Head posture and chest movements were assessed using a photogrammetric method. RESULTS: The results confirmed the existence of a negative correlation between head position in the sagittal plane and movements of lower ribs. Forward head posture resulted in lower amplitude of costal arch motion: for the transverse plane Spearman's R = -0.296, for the frontal plane; -0.273, -0.289. Tilting the head in the frontal plane also influenced the change in the biomechanics of breathing and contributed to a reduction of respiratory movements of the lower ribs Spearman's R = -0.260. CONCLUSIONS: Changing the position of the head causes disturbances in the three-dimensional shape of the chest and its respiratory movements.

Respiratory chest movement measurement as a chair quality indicator--preliminary observations.

Regardless of the constantly increasing time man is spending in a sitting position, there is still a lack of objective chair quality assessment criteria. The aim of this paper is to find the answer to whether respiratory chest movement measurements can be a chair quality indicator. The study included 34 participants (mean 34.7 years±5.2). Their chest movements were assessed using respiratory inductive plethysmography while sitting on two subsequent chairs. Significant differences in chest movements depending on chair type were observed concerning the breathing duct (upper and lower) and breathing movement amplitude. The amplitude of the upper respiratory track in the first chair was higher (239.4 mV) compared with the second seat (207.3 mV) (p=.018). The analyzed parameters of respiratory chest movement may become a helpful indicator for design and selection of chairs which enable people to both work and relax in the most ergonomic conditions.

[Comparative analysis of distribution on the sole surface of arched feet and flat feet]. / Analiza porównawcza dystrybucji nacisków na powierzchni podeszwowej stóp prawidlowo wysklepionych, oraz stóp plaskich.

The authors of this paper have carried out a hypothetical assessment of the difference in the distribution of pressure on the surface of the sole of correctly arched feet, and also of flat feet. They aimed to find out if there are significant differences in the spread of the pressure, and also at which levels of incidence they are highest. The authors carried out the research based on clinical material comprising 133 subjects (266 feet), including 75 females (56.4%) and 58 males (43.6%). The age of the subjects ranged from 10 to 83 years old, with the average age being 41.8 years old. The subjects were divided into three age groups. There were 22 subjects (16.5%) in the first group, aged from 10 to 20 years of age, 37 subjects (27.8%) aged 21 to 40 in the second group, and 74 subjects (55.6%), aged over 40 in the third group. All those included in the research underwent graphic contour testing in accordance with the Clarke method, and pedobarographic testing based on PEL 38. Results obtained suggest that the graphic contour testing is an important element of flat foot diagnosis, and that increased levels of pressure on the soles of flat feet are concentrated in the middle of the foot and below the first bone in the centre of the foot.