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In this work, the authors focused on analyzing the energy efficiency and dynamics during car acceleration, featuring investigation of acceleration dynamics under various acceleration intensities. The tests were performed in the speed range between 45 km/h and 120 km/h, at a constant gear ratio. This enabled obtaining variable dynamic parameters of the acceleration process, ranging from about 0.1 to 1.4 m/s2 , and recording variation in fuel consumption from 6.28 to 27.03 dm3 /100km. The study focused on determining the relation between fuel consumption, energy efficiency and vehicle acceleration depending on the available drivetrain power. The relation between fuel consumption and vehicle acceleration was described by using the dynamic index. The proposed dynamic index takes into account the energy (from burned fuel) and vehicle acceleration intensity to obtain an objective metric for characterizing the acceleration process. The aforementioned index takes the form of the passenger car movement energy quality index and can be related to widely known physical properties, thus ensuring its universality. The index expresses the energy expenditure within the time needed to accelerate a vehicle weighing 1kg by a 1m distance. As opposed to other criteria that are applied to the assessment of passenger cars dynamics, the index shows a high determination coefficient R2 in excess of 0.99, and can be used as a universal metric to test other vehicle types.

The paper presents an analysis of energy consumption in a Plug-in Hybrid Electric Vehicle (PHEV) used in actual road conditions. Therefore, the paper features a comparison of the consumption of energy obtained from fuel and from energy taken from the vehicle’s batteries for each travel with a total distance of 5000 km. The instantaneous energy consumption per travelling kilometre in actual operating conditions for a combustion engine mode are within the range of 233 to 1170 Wh/km and for an electric motor mode are within the range of 135 to 420 Wh/km. The average values amount to 894 Wh/km for the combustion engine and 208 Wh/km for the electric motor. The experimental data was used to develop curves for the total energy consumption per 100km of road section travelled divided into particular engine types (combustion/electric), demonstrating a close correlation to actual operating conditions. These values were referred to the tested passenger vehicle’s approval data in a WLTP test, with the average values of 303 Wh/km and CO2 emission of 23 g/km.

Background: Patients with diagnosed keratinocyte carcinomas (KCs) have an increased risk of subsequent skin cancers development. Current studies indicate that patients with subsequent tumors should be followed up regularly. However, none of the studies indicate the connection between the specific subtypes and an increased risk for further KCs development. The study assesses the differences in the risk of developing a subsequent skin cancer after a previous diagnosis of KC, especially considering individual types of skin malignances, and identifies potential factors associated with an increased risk of new cutaneous tumor describing non-invasive diagnosis and monitoring. Methods: Pathology and medical records were examined to identify the characteristics of patients with multiple KCs diagnosed between 1999 and 2019. Results: The study group comprised 13,913 KCs occurring in 10,083 patients. Multiple KCs were observed in 2300 patients (22.8%). The analysis showed aggressive subtypes, multiple tumors, and male sex as significant prognostic factors. Conclusions: The most crucial risk factors for developing subsequent KC are being of a male gender, an aggressive tumor subtype, and previous history of multiple skin cancers. Basal cell carcinoma subtypes, such as infiltrative basosquamous, with aggressive growth patterns predispose not only to increased risk for the recurrence but are also expected to be at higher risk of subsequent KCs.

Background: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease. An important role of innate immune dysregulation in the pathogenesis of HS has been highlighted. S100A7 (psoriasin) is an innate, antimicrobial protein that exerts proinflammatory and chemotactic action. Objectives: The objective of the study was to investigate serum concentrations of S100A7 in individuals with HS as compared to healthy controls. Further, we evaluated the expression of S100A7 in lesional HS skin as compared to perilesional (clinically uninvolved) HS skin and normal skin. Methods: Serum concentrations of S100A7 were evaluated with a commercially available ELISA kit. The expression of S100A7 in the skin was assessed using qRT-PCR and immunofluorescence staining. Results: We found increased expression of S100A7 in lesional HS skin as compared to perilesional HS skin (p = 0.0017). The expression of S100A7 in lesional HS skin was positively associated with serum C-reactive protein concentration and the severity of disease according to Hurley staging. The serum concentration of S100A7 in individuals with HS was decreased as compared to healthy controls and patients with psoriasis. Conclusions: Upregulated in lesional HS skin, S100A7 may enhance the inflammatory process and contribute to the HS pathogenesis.

Basosquamous carcinoma (BSC) is a rare non-melanoma skin cancer that shares the characteristic features of both basal and squamous cell carcinomas (BCC, SCC). Our research enables better characterization of BSC in comparison to high-risk subtypes of BCC and SCC. Paper includes a retrospective analysis of BSC cases regarding sex, age, number of tumors and anatomical distribution in comparison to BCC and SCC evaluating the differences and defining the implications. Histologically confirmed carcinomas recorded between 1999 and 2019 were studied. 181 diagnosed BSC cases were identified, making this study the largest cohorts of BSC patients reported worldwide. Most cases were reported on head and neck. Analysis of facial anatomic distribution shows that most commonly affected sites were the nose (43%) and the cheek (25%). The age at excision of metatypical BCC was higher than those of low-risk BCC (P P = 0.20). We revisited that the concept of BSC is the most similar to high-risk subtypes of BCC. Patients with diagnosed BSC have higher risk of second nonmelanoma skin cancer. Therefore, the frequency of follow-up examination should be adjusted to the individual risk of another skin cancer.

The analysis of energy consumption in a hybrid drive system of a passenger car in real road conditions is an important factor determining its operational indicators. The article presents energy consumption analysis of a car equipped with an advanced Plug-in Hybrid Drive System (PHEV), driving in real road conditions on a test section of about 51 km covered in various environmental conditions and seasons. Particular attention was paid to the energy consumption resulting from the cooperation of two independent drive units, analyzed in terms of the total energy expenditure. The energy consumption obtained from fuel and energy collected from the car’s batteries for each run over the total distance of 12,500 km was summarized. The instantaneous values of energy consumption for the hybrid drive per kilometer of distance traveled in car’s real operating conditions range from 0.6 to 1.4 MJ/km, with lower values relating to the vehicle operation only with electric drive. The upper range applies to the internal combustion engine, which increases not only the energy expenditure in the TTW (Tank-to-Wheel) system, but also CO2 emissions to the environment. Based on the experimental data, the curves of total energy consumption per kilometer of the road section traveled were determined, showing a close correlation with the actual operating conditions. Obtained values were compared with homologation data from the WLTP test of the tested passenger car, where the average value of energy demand is 1.1 MJ/km and the CO2 emission is 23 g/km.

The analysis of the vehicle acceleration process is a current topic based on the aspects related to the general characteristics of the car, its parameters, design, drive unit performance, and the influence of external factors. Therfore in the article, the authors assessed the dynamic and energy parameters of the car motion, in which the intensity of acceleration of the car with different intensities was examined. Acceleration was carried out in two variants, the first for a normal internal combustion engine and the second for the same engine but additionally equipped with a short-term boost system. In this way, it influences the increase in power and energy in the car drive system, changing its acceleration intensity. Variable car acceleration intensity was obtained in the range from 0.12 to 1.37 m/s2 , and energy consumption at the level of 0.4 to 1.2 MJ in the distance of 1/4 mile. The article proposes a combination of energy parameters and engine power in order to assess the acceleration dynamics, for this purpose, the specific energy consumption of the car was determined, ranging from 0.35 to 2.0 J/(kg∙m), which was related to the engine power, denoting it with the dynamics index. The study focuses on the assessment of the relationship between the specific energy consumption and acceleration of passenger cars in the available powertrain system using a new dynamics index. The proposed dynamics index combines the energy and dynamic parameters of the car to be able to objectively quantify the acceleration process.

Introduction Rhinophyma is a relatively rare form of rosacea, while basal cell carcinoma (BCC) is the most frequent skin cancer in humans – both diseases prevail in the elderly. Aim To analyse patients with rhinophyma treated surgically in the Dermatosurgery Unit and look for possible cases with BCC within the rhinophyma. Material and methods We performed a retrospective review of all treated rhinophymas in the Dermatosurgery Unit in 2004–2019. Results Among 140 rhinophyma patients 2 (1.4%) subjects with concomitant clinically diagnosed and histologically confirmed BCC were found, with BCC located in the hypertrophic tissue of the nose. There were no patients with BCC located in other anatomical regions of the skin. Both of these patients were in more advanced age. Conclusions Taking into consideration these two conditions: advanced age and anatomical location, typical for BCC, one may speculate that the development of BCC within rhinophyma is rather a simple coincidence. However, more numerous series of patients with rhinophyma are needed to clear the controversy of BCC within rhinophyma hypertrophic tissue.

The article presents the possibility of using self-learning control algorithms to manage subassemblies of an internal combustion engine in order to reduce exhaust emissions to the natural environment. In compression ignition (CI) engines, the issue of emissions mainly concerns two components: particulate matter (PM) and nitrogen oxides (NOx). The work focuses mainly on the possibility of reducing the emission of nitrogen oxides. It is assumed that the particularly problematic points when it comes to excessive emission of harmful substances are the dynamic states in which combustion engines operate constantly. In dynamically changing operating points, it is very difficult to choose the right setting of actuators such as the exhaust gas recirculation (EGR) valve to ensure the correct operation of the unit and the minimum emission of these substances. In the light of the above, an attempt was made to develop a self-learning mathematical model, which can predict estimated emission levels of selected substance basing on current measurement signals (e.g. air, pressure, crankshaft rotational speed, etc.). The article presents the results of the estimation of nitrogen oxides by the trained neural network in comparison to the values measured with the use of a sensor installed in the exhaust system. The presented levels of estimated and measured results are very similar to each other and shifted over time in favour of neural networks, where the information about the emission level appears much earlier. On the basis of the estimated level, it shall be possible to make an appropriate decision about specific settings of recirculation system components, such as the EGR valve. It is estimated that by using the chosen control method it is possible significantly to reduce the emission of harmful substances into the natural environment while maintaining dynamic properties of the engine.

The study concentrated on slip phenomenon occurring at hydrokinetic converter in passenger car transmission system. Optimization of modern automatic transmission systems aims, on the one hand, to further increase the comfort of use, and on the other hand to improve the efficiency and reliability operation of individual components, in such a way as to ultimately result in lowering fuel consumption and also harmful emissions. One of the important factors affecting the mentioned transmissions properties as a whole system is the slip phenomenon occurring between the pump and the hydrokinetic converter turbine. The study presents the results of research on ZF 4HP20 and Fuji Hyper M6 gearboxes operating in vehicle transmission systems. The tests were carried out using the MAHA MSR 500 chassis dynamometer during driving at chosen test cycles. The research covered the transmission systems operating according to selected control algorithms affecting not only the gear shifting strategy but also the operation of the lock up clutch causing the transmissions slip values. As shown by the conducted research, the algorithm controlling the operation of the torque converter can have a significant influence on their operating indexes. The conducted analyses indicate the possibilities of improving the transmission operating indexes, especially in urban driving cycles.

The study concerns the use of biogas as a fuel for supplying a modified self-ignition engine. As a result of the modifications made, the compression ratio was reduced and the engine was equipped with an ignition system and an electronically activated engine throttle. The changes have made it possible to burn biogas in a high compression ratio engine. The paper presents the results of research conducted on a low power cogeneration system with engine that drives an electrical machine cooperating with a 380/400 V network. The analysis includes, among other things, the possibility of producing electricity using biogas. The paper presents the influence of regulatory parameters such as the volume and composition of the supplied gas mixture and the degree of throttle opening on the obtained engine operation indicators and the driven electric machine. The tests were carried out in relation to the obtained ecological indicators depending on the concentration in the exhaust of such substances as: HC, CO, NOx.

The article deals with measurements of ability to maintain the balance conducted for soldiers who were wounded during combat missions. Measurements were carried out both in real and virtual environment. Tests in the real environments were performed with open and closed eyes. Tests in the virtual environment were performed with the use of spatial sceneries which were immobile or were oscillating in AP direction. Analysis of results was conducted both in time domain and frequency domain. All results were compared with the literature results obtained for healthy people. Results obtained for soldiers differed from the results of healthy people. According to the obtained results, it can be concluded that the studies of the ability to maintain the balance should be carried out both in static and dynamic conditions, and the analysis of the obtained results should be carried out both in time and frequency domain.

Purpose Analysis of human gait as well as diagnosis of human locomotion organ should always be conducted with velocity of gait equal to Preferred Walking Speed (PWS). The literature review shows that the PWS value is not the same in real and virtual environment. The aim of this study was to determine PWS values in both environments and to specify values of parameters used in equations enabling PWS calculations on the basis of lower limb length. Methods Research-related tests involved 40 subjects walking on the treadmill and wearing HMD goggles. The spatial scenery made participants feel like during a walk in the park. The tests included measurements of displacements of the COP, allowing for the calculation of the Lyapunov exponent and Floquet Multiplier. Both coefficients were used to identify stability at various gait velocities. Results The analysis revealed that the PWS in relation to gait on the treadmill with VR was lower than the PWS without VR. The final stage of research involved the determination of new values of coefficients of the formula enabling the identification of the velocity of comfort of gait in VR. Conclusions Obtained results proved that PWS in real and virtual environment are different. The lower values were obtained for measurements in VR. On the basis of these results, value of the "a" coefficient, used in PWS calculations on the basis of lower limb length, was re-determined. The new value makes it possible to assess PWS for gait conducted on treadmill in virtual environment, what can be very important in gait evaluation.

An attempt has been made to clarify the effect of wide-ranging control of the exhaust gas recirculation system on the cylinder pressure and ecological engine performance. This publication contains the results of tests performed on the CI (compression ignition) engine of the off-road vehicle mounted on the test bench. The study was based on advanced EGR control with a proportional valve and a very efficient exhaust gases cooling system. Analysis of the test results is based on the cylinder pressure and the concentration of NOx and PM components at exhaust gases. The study included the influence of the exhaust gas recirculation system control on parameters such as differential pressure, MBF, and relative NOx and PM emissions. As demonstrated by the analysis conducted, the EGR valve control method and the exhaust gas cooling intensity significantly affect the cylinder pressure and its ecological performance.

Biologics seem to offer a promising nonsurgical approach in hidradenitis suppurativa (HS), especially in disease with highly pronounced inflammation. Recent studies revealed increased expression of a broad range of cytokines in lesional HS skin, including interleukin (IL)-17.This study was undertaken to determine IL-17 serum levels in this group of patients.Our study was conducted on a group of 86 patients between 16 and 72 years of age with HS. A total of 86 matched healthy volunteers constituted the control group. Enzyme-linked immunosorbent assay kits were used to quantify IL-17 serum concentration.The mean IL-17 serum level of patients with HS was 3.68 ± 2.08 pg/mL, which was significantly elevated (P .0001) compared with that found in healthy volunteers (2.5 ± 1.11 pg/mL). Moreover, there was a tendency toward higher serum concentrations of IL-17 in patients with more advanced disease (P = .005). Disease duration; patient sex, age, and body mass index; and smoking habits were not determining factors for IL-17 serum concentration.Hospital-based study population was a limitation, as was a lack of posttreatment assessment.In light of our findings and literature on increased expression of IL-17 in HS lesions, evaluating the clinical effectiveness of using anti-IL-17 agents in the treatment of patients with HS is justified.

The study analyses the effect of acceleration intensity on energy consumption and drive efficiency during a road test for a passenger vehicle. The acceleration was carried out from the assumed initial speed to the target speed determined appropriately for individual gear ratios. The tested speeds include values of 40-130 km/h. The intensity of the acceleration process resulted from the selected settings in the powertrain, such as the throttle opening with values from 30 to 100% and gearbox ratio selection. The tested mean accelerations covered the values from 0.2 to 1.5 m/s2. For individual sets of acceleration intensity, gearbox ratio and throttle opening, the unit energy consumption curves and the total efficiency courses of the powertrain system were determined. The average values of the powertrain efficiency obtained during the acceleration tests amounted to the range of 19.38–25.67%, while an increase in the average efficiency was found with a decrease in the gear ratio value and also the influence of the throttle opening was observed. The study assessed also the relationship between the average acceleration for the speed gaining phase and unit energy consumption, where the acceleration increment by 0.1 m/s2 causes a proportional increment in unit total energy consumption by about 0.15J·(kg·m)−1, regardless of the acceleration intensity.

WstępCelem pracy była prospektywna ocena jakości kompresji klatki piersiowej podczas symulacji ciągłego masażu serca na manekinie w czasie rzeczywistym, wykonywanego przez czynnych zawodowo ratowników medycznych, z uwzględnieniem ich BMI.Materiał i metodyBadanie przeprowadzono w grupie 17 ratowników medycznych oraz 21 studentów kierunku ratownictwo medyczne i wykładowców uczelni. Podczas próby każdy badany wykonywał nieprzerywany masaż zewnętrzny serca na manekinie do osiągnięcia punktu końcowego, jakim był czas 15 minut lub odmowa dalszego wykonywania zadania.WynikiŚrednia głębokość wykonywanych uciśnięć zmniejszała się istotnie od pierwszej (40,66, SE ± 0,80 mm) do czwartej minuty badania, osiągając wartość 38,21 SE ± 0,95 mm. Średnia częstość uciśnięć klatki piersiowej istotnie różniła się od szóstej minuty (123,69 SE ± 2,55/min) w stosunku do wartości wyjściowych (120,97 SE ± 2,83/min). W dziesiątej minucie średnie wartości głębokości uciśnięć oraz częstości masażu klatki piersiowej osiągnęły odpowiednio 36,62 SE ± 1,04 mm oraz 128,06 SE ± 2,43/min. Istotnym czynnikiem wpływającym na głębokość kompresji klatki piersiowej była przynależność do grupy czynnych zawodowo ratowników medycznych. Średnia głębokość ucisku w całym badanym przedziale czasowym w grupie nie-profesjonalistów wynosiła 36,03 SE ± 1,22 mm, podczas gdy w grupie profesjonalistów – 40,06 SE ± 1,37 mm. Drugim istotnym czynnikiem różnicującymi zakres głębokości kompresji klatki piersiowej był czas oraz BMI ratownika. U osób z BMI > 25 jedynym różnicującym punktem czasowym był początek badania, w którym średnia głębokość ucisku wynosiła 41,97 SE ± 1,12 mm.WnioskiMasa ciała ratownika jest istotnym czynnikiem wpływającym na uzyskanie głębszej kompresji klatki pier-siowej. Profesjonalni ratownicy są w stanie prowadzić skutecznie ciągłą kompresję klatki piersiowej w dłuższym czasie, osiągając zadowalające ugięcie oraz częstotliwość jej kompresji.

Gait is the most important form of human locomotion and can be decribed by kinematics quantities and stabilographics paramaters. It is possible to determie those parameters from the distribution of forces on the ground. The purpose of this study is determining of repeatability of gait on treadmill in virtual reality. Thirty-two healthy adults have been exmained. In this study each person has been tested 6 times (natural gait on the threadmill and 5 times gait on the treadmil in virtual reality). Between each part of the study was 240 s break, during that person was stimulated by various stimuli, like increseed or decresed speed of treadmill or virtual scenery. All this to disperse the examined person and to maximize the destabilization of the posture of this person. In this study was concluded that gait on the treadmill in virtual reality is repetitive in reference to measured values of selected kinematic parameters determined by distribution of forces on the ground. Results of this study were confronted with literature review. The study are first attempt describing of impact of VR environments on human gait.

An essential aspect of rehabilitation is the maintenance of balance both when standing and in gait. Clinical practice sees equipment enabling the dynamic evaluation of posture stability involving the use of virtual reality. The use of virtual reality in rehabilitation supporting processes and, particularly, with respect to the improvement of motor activity and ability to balance the body, requires that the above-named technology should be tested in terms of its effect on humans. The objective of the tests was to assess changes in the ranges of movements of the COP during gait on treadmill. The assessment was based on measurements of the distribution of pressure on the ground in a system enabling the projection of sceneries created by means of virtual reality. The tests were performed using two different gait velocities as well as matched and mismatched velocity of the scenery motion in relation to actual treadmill motion conditions. The tests involved 32 individuals (26 females and 6 males) aged 23 (SD 1,8). The investigations consisted of 6 stages, in which a person provided with a safety harness walked on a treadmill and was subjected to measurements focused on the distribution of forces exerted by feet on the ground during gait. The tests justified a conclusion that the projection of a moving scenery performed using an HMD headset increased ranges of movements of the COP on the ground during gait on a treadmill. The mismatch between the treadmill velocity and the velocity displayed in virtual reality changed the range of the COP displacement in the AP direction only in the cases of the treadmill velocity changes. The test results constitute the first stage of research on the impact of virtual reality on the stability of human gait.

Fencing is a combat sport in which fencers compete in three weapons: foil, saber and epee. They differ from each other in blade type, valid target and scoring technique. Although the fundamental role of speed, coordination and sensory-motor skills in fencing is indisputable, merely rapid and correct accomplishment of a movement does not ensure success. Outright bout against an opponent requires high level of perceiving, information processing and accurate decision-making. Thus, in fencing, as a ‘game of anticipation and deception’, technical abilities are just a tool used to execute chosen strategy and tactics. The repeatability of joints’ movements relevant to the lunge performance was measured. Shoulder, elbow and wrist joint of the upper arm, hip joint and knee leg movements were checked in order to match and determine the number of necessary recordings. The study covered 10 athletes, 6 saber and 4 epee fencers, members of Polish National Team. There is a repeatability in measured movements. The weak and negative correlation coefficient is observed just between several subjects. The strong correlation coefficient was noted across trials within a single subject. This result implies, that frequently repeated movements create stable movement patterns which is individual for each of the subjects. According to individual character of performed actions, animation database should contain possible highest number of recorded athletes. Just widening of database can provide expected level of diversity to fencing training and prevent the effect of ‘learning’ just one opponent.

Interactive devices supporting the rehabilitation of upper limbs are becoming more and more popular among physicians and physiotherapists. It has been observed that the motivation increases in patients while doing exercises aided by computer systems. A controller developed in this research supports the process of diagnosis and therapy. It has been made in the form of a glove worn on the upper limb. The device enables the patient to control an application in the virtual world of computer graphics by detecting the movements of the limb and flexion of two selected fingers. This work encompasses the concept of the device, documentation of the prototype and verification of its functioning. The verification was conducted in two stages: the first one focused on the verification of the operation of tensometric flex sensors, and the second on the verification of indications of an orientation sensor. The verification tests determined the hysteresis of tensometric sensors and a mean-square error as well as a correlation coefficient between different system orientation values measured by means of various measuring systems. The verification enabled the determination of uncertainty of parameters measured as well as functionality of the device.

Indexing methods are very popular in terms of determining the degree of disability associated with motor dysfunctions. Currently, indexing methods dedicated to the upper limbs are not very popular, probably due to difficulties in their interpretation. This work presents the calculation algorithm of new SDDI index and the attempt is made to determine the level of physical dysfunction along with description of its kind, based on the interpretation of the calculation results of SDDI and PULMI indices.23 healthy people (10 women and 13 men), which constituted a reference group, and a group of 3 people with mobility impairments participated in the tests. In order to examine possibilities of the utilization of the SDDI index the participants had to repetitively perform two selected rehabilitation movements of upper extremities. During the tests the kinematic value was registered using inertial motion analysis system MVN BIOMECH.The results of the test were collected in waveforms of 9 anatomical angles in 4 joints of upper extremities. Then, SDDI and PULMI indices were calculated for each person with mobility impairments. Next, the analysis was performed to check which abnormalities in upper extremity motion can influence the value of both indexes and interpretation of those indexes was shown.Joint analysis of the both indices provides information on whether the patient has correctly performed the set sequence of movement and enables the determination of possible irregularities in the performance of movement given.

The aim of the study was to examine the influence of different types of virtual sceneries and frequencies of movement of visual disturbances on stabilometric values as well as whether individual sceneries and changing frequency can minimize effect of adaptation of tested person to applied disturbances.There were 23 healthy participants. A person has been standing on a Zebris stabilometric platform. Virtual 3D environment was displayed by means of HMD Oculus Rift system. An open (a meadow) and closed (a room) sceneries were used. The sceneries moved along the sagittal axis and rotated around horizontal axis. The measurement lasted 30 seconds and in the middle of it frequency of translational movement was changed from 0.7 Hz to 1.4 Hz or from 1.4 Hz to 0.7 Hz.The data were reported as medians of COP velocity and ellipse area. Visual disturbances caused the increase of these values in comparison with the tests conducted with open eyes. Results divided into periods (the first and the second 15 seconds) showed that in the first half of the test values were higher compared to the second half. The comparison of values obtained for open and closed scenery showed that higher values were recorded for open scenery.The comparison of both types of sceneries on the basis of COP velocity and ellipse area showed that open scenery had a greater impact on the measured stabilometric values. It was found out as well that people got accustomed to the applied disturbances, but this effect was lower in the open scenery.

One of the way to get rid of the spine issues is using chairs with a movable seat. The essence of chairs with a movable seat is to increase the range of motion of pelvis movement. Natural ability to maintain the upright position of the body can cause the increasing of pelvis movement. That requires the involvement of the spine stabilizing muscles. The construction of chairs with a spherical base should provide stability and prevent from slipping away from the chair. At the same time chairs with spherical base should provide mobility to force pelvis movements. We made an ergonomic analysis of chair with spherical base. Studies have determined the stability of the seat and the range of pelvis movements. These measurements used the whole body kinematics. The ergonomic assessment of the spherical seat required investigation to determine the following parameters: center mass displacement, lean of spherical chair and kinematics of the human body.