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Background Balance disorders in patients diagnosed with Parkinson’s disease (PD) are associated with a change in balance-keeping strategy and reflex disorders which regulate the maintenance of vertical body posture. Center of foot pressure (COP) displacement signals were analyzed during quiet standing experiments to define such changes. The research aimed to apply stock exchange indices based on the trend change analyses to the assessment of a level of the Parkinson disease progression on the grounds of the analysis of the COP signals. Methods 30 patients in two stages of PD, 40 elderly participants, and 20 individuals at a young age were studied. Each person was subjected to 3 measurements with open and closed eyes. A technical analysis of the COP displacement signal was performed, and the following quantities were determined: indices related to the number of trend changes (TCI), indices defining a mean time (TCI_dT), and mean displacement (TCI_dS) and mean velocity (TCI_dV) between such changes. Results The results indicate a higher TCI value for PD than for CG (p

Assessment of human balance is one of the most common diagnostic tests, both in medical applications and during sports training. Many new methods of measuring are introduced in these studies; however, the analysis of results is still carried out mainly based on the values determined in the time domain – the average COP speed or the ellipse field of the prediction. The aim of the current work is to present the possibilities for the practical application of frequency analyses in assessment of the ability to maintain body balance as a method supplementing standard analyses. As part of the study, measurements of the ability to maintain balance in sensory conflict conditions introduced in the form of an oscillating, three-dimensional, virtual scenery were carried out. 27 healthy volunteers (13 women and 14 men) took part in the study. The three-dimensional scenery, presented by means of the Oculus system, oscillated in the sagittal plane with frequencies equal to 0.7 Hz and 1.4 Hz. The frequency value during the measurement was constant or changed in the middle of the test. Measurements were conducted on the FDM Zebris platform. The results were analyzed using developed coefficients determined on the basis of the Short-time Fourier transform (STFT). The use of frequency-domain analyses confirmed that in the COP movement, one can observe a cyclical component corresponding to following the scenery, as well as the appearance of other cyclical components whose observation is important in terms of assessing the ability to maintain balance. It has been shown that the changes in the average COP speed that occur during the measurement can result from changes related to the movement of following the scenery as well as additional body movements indicating a greater or lesser loss of balance. It has been shown that there are differences in the COP movement provoked by the movement of the surrounding scenery, which depend on the parameters of the introduced disturbances – something that can only be observed in results obtained in the frequency domain. The conducted research shows that in measurements involving the ability to maintain one’s balance conducted in sensory conflict conditions, standard time-domain analyses should be supplemented with other types of data analysis, e.g. frequency domain analyses.

Purpose: The purpose of the study was to determine how a stimulus presented in the virtual reality environment as a simulation of a fall off the stairs, triggers a loss of balance. The study also examined if the head movement measurements and the analysis in the frequency domain could increase the range of interpretation. Methods: 11 healthy individuals were tested, two [A1] were identified as more susceptible to the introduced disturbance, and one reported having dizziness, car sickness and fear of heights. Measurements of center of pressure (COP) and head positions were performed in the real and in the virtual environment. The beginning of the simulation was either unexpected or preceded by a signal. The analysis included standard parameters determined in time domain as well as the amplitude of the first harmonic from the fast Fourier transform (FFT). Results: The analysis did not reveal statistically significant differences between results obtained: in real and virtual environments, with and without the warning signal. It was possible to notice the effect of virtual disturbance in the three selected individuals; this was particularly evident in the analysis of the first harmonic of the FFT. Conclusions: The conducted tests revealed that the limitation of the analyses exclusively to the time domain could be insufficient for a comprehensive interpretation. The effect of introduced disturbance was particularly noticeable in the analysis of the first harmonic for head movement. The application of this parameter could enable a more accurate investigation of a strategy aimed at maintaining balance.

Purpose We investigated whether an increase in muscular tone induced by the information about imminent posture destabilisation brings a positive result and prevents such destabilisation. Methods We measured forward and backwards movements of 38 participates (27 females and 11 males, aged 23 (SD 2.6)) on the treadmill (forward and backward movements). All participants were subject to three test condition trials (Tr): 1) subject did not know the nature and time of perturbation (Tr1); 2) subject knew the nature of perturbation but did not know time (Tr2); 3) both the time and nature of perturbation were known precisely (Tr3). The tests resulted in the determination of muscular activity connected with a postural adjustment as well as values of pressure exerted by the forefoot on the ground, and the angle of flexion in the knee joint. Results In terms of postural adjustments it was possible to observe statistically significant differences in muscular activity between Tr1 and Tr2 refer to Tr3. No statistically significant differences were identified in all phases as regards values of forefoot pressure and those concerning the angle of flexion in the knee joint. An increase in the muscle tone before perturbation was correlated with the displacement and the velocity of the COP after perturbation. Conclusions These data indicate that knowledge of the expected time of perturbation is responsible for postural adjustment. Furthermore, muscle tone resulting from an adjustment of perturbation and responsible for the stiffening of lower limbs triggered greater displacement of the COP after perturbation.

Purpose: The aim of the study was to demonstrate the possibility of using stock exchange indices to assess the ability to maintain balance as a supplement to analyzes using values determined in the time and frequency domains. Methods: 83 healthy people (56 females, 27 males, age years 21 SD = 1.3 years) participated in the research. Measurements were performed with open and closed eyes and in the virtual environment with two sceneries oscillating at four frequencies. The results determined in the time and frequency domains were analyzed in relation to the results calculated with the use of stock exchange indicators for which the Trend Change Index was formulated. Performed measurements made it possible to determine the average COP speed, the average COP speed and range of movement towards AP, power spectral density PSD and stock exchange indices. Results: In the case of PSD values for the ranges above and below 0.5 Hz, statistically significant differences occurred for most measurements. Obtained values of TCI coefficient were similar and no statistically significant differences were observed. The maximum values of the PSD medians were obtained in trials with the oscillating scenery. Conclusions: Conducted analyzes showed that use of stock exchange indicators broadens the interpretative possibilities of COP measurements by determining the number of consecutive skips (changes in the direction) of the COP and prioritizing according to the times between them. The applied stock market analysis methods also filtered out changes in the position resulting from noises that could not be removed with the use of standard low-pass filters.

BACKGROUND: Commonly used analyses of the ability to maintain balance do not take into account momentary changes appearing during the entire analysis. Looking at the nature of the COP and COM curves, a conclusion can be drawn that such trends could be investigated applying methods used for the technical analysis of stock exchange rates.OBJECTIVE: The objective of the study was to determine whether the Moving Average Convergence/Divergence indicator (MACD) could be used in the analyses concerning the assessment of the ability to maintain balance.METHODS: The study group was consisted of 85 healthy individuals in the real environment tests and 12 healthy individuals in the virtual environment tests (with a oscillating scenery). Performed calculations enabled the identification of time intervals between successive trend changes in relation to the COP displacements.RESULTS: Test results revealed that, when standing, the most frequently appearing time intervals between successive trend changes were restricted within the range of 0.1 s. to 0.5 s.CONCLUSIONS: The above-presented trend was observed both in relation to the measurements conducted in the real environment and those performed in the oscillating virtual environment. The foregoing could indicate that the changes are characteristic and indispensable for the proper maintaining of balance by humans.

Purpose: The aim of this study was to develop a method to implement muscle forces to a numerical model of a dummy and to evaluate the effect of muscle activation on driver behavior during a frontal collision. The authors focused on the forces acting at the knee, hip, and elbow joints. Methods: The authors carried out torque measurements in joints using the Biodex System 4. Then, the previously developed numerical models were modified by introducing the joint torque values. Moments of force were introduced as a function of the rotation angle. During research, numerical simulations were carried out in three stages: in the first stage, a full vehicle crash was analyzed to determine the change of velocity of the vehicle interior; in the second stage, subsidence of the system was realized; in the third stage, a frontal crash was simulated. The models considered the operation of the sensors, airbag and seat belt tensioning system. Results: A numerical model with the active response of the dummy to the change in position during impact was developed. The results of the dynamic analysis were used to analyze the impact of muscle activation on dummy behavior. The change in shoulders rotation angle, the lateral and vertical displacement of the dummy’s center of gravity, and the forces acting between the dummy and the seat belt were compared. Conclusions: The effect of muscle action on the behavior of a dummy during a frontal collision was determined.

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.

Purpose The objective of the work was to determine biomechanical parameters influencing loads affecting the musculoskeletal system and shock absorption during the landing phase in Grand Jete, Entrelace and Ballonne. Methods Motion kinematics measurements of the landing phase in GrandJete, Entrelace and Ballonne were carried out using the optical APAS system, and measurements of the GRF components - using Kistler platform. The research was carried out for three professional dancers. Kinematic and kinetic parameters of the landing were analysed. Results The mean maximum GRF value in relation to the classical dancer amounted to 8.16 ± 1.37 N/BW. During landing, the joints of the lower limb are affected by external force moments of high values (ankle - 3.04 ± 0.54 [Nm/BW], knee - 7.56 ± 5.53 [Nm/BW], hip - 10.97 ± 6.80 [Nm/BW]). The maximum value of the external force moments in the joint were strongly negatively correlated with the value of the angle in the hip joint at the moment of the first contact with the ground. It was noticed that the obtainment of maxGRF was preceded by a decrease in kinetic energy of approximately 50%. Conclusions Factors affecting loads present in the musculoskeletal system during the shock absorption of a leap are: GRF values, the values of external force generated inside the joints and a change in the value of kinetic energy. The safe shock absorption after landing is influenced by properly positioned limb at the moment of the first contact, a greater range of movements in the joints and longer time from the moment of the first contact to the obtainment of maxGRF.

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.

PURPOSE: The aim of the study was to assess and compare kinematic and dynamic aspects of ‘grand pas de chat’ dancing element performed by ballet dancers: a female and a male. METHOD: Tests were carried out with the use of the motion analysis system and the force plate. RESULTS: The research enabled kinematic and dynamic analysis of elements performed by dancers. The results made it possible to indicate when, during dancers’ movement, the greatest loads in their body occur. Also differences in kinematics of landing performed by female and male were observed. CONCLUSION: According to directives on technique and esthetics required in classical ballet by Vaganova [1] female rather than male performance of landing phase after ‘grand pas de chat’ was done safer. For amateurs an instruction on safe landing preserving sufficient amortisation should be incorporated.

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.

Unstable gait is also a frequent problem in patients with neurological dysfunctions. It proves to be essential to develop methods of objective diagnostics of human mobility and early detection of defects which are often a result of more serious conditions. The aim of this research is to develop methods of evaluation of gait instability with open and covered eyes on a treadmill on the basis of selected kinematic quantities.

This study investigated how spatial projection systems influences body balance including postural stability. Analyzing precisely defined frequency bands of movements of the center of pressure makes it possible to determine the effectiveness of the balance system&rsquo, s response to disruptions and disorders and may be used as an indicator in the diagnosis of motor dysfunction. The study involved 28 participants for whom the center of pressure was assessed in a test with open eyes, closed eyes and with virtual reality projection. Percent distributions of energy during wavelet decomposition were calculated. Changes in body stability were determined for the virtual reality tests and these changes were classified as an intermediate value between the open-eyes test and the closed-eyes test. The results indicate the importance of using safety support systems in therapies involving Virtual Reality. The results also show the necessity of measurements times in stabilographic evaluations in order to conduct a more thorough analysis of very low frequencies of the center of pressure signal.

The aim of this study was to formulate a new balance disturbances coefficient enabling objective balance assessment on the basis of fast Fourier transform curves. The article presents the method of coefficient calculation and possible ways of its interpretation.11 healthy participants took part in the experiment. There were four measurements: two in real environment with eyes open and eyes closed as well as two in virtual environment with scenery (surroundings) oscillating with frequency 0.7 Hz and 1.4 Hz. Scenery was displayed by means of the Oculus Rift system, whereas position of centre of pressure was measured with the use of Zebris FDM-S platform. Obtained centre of pressure positions were used to calculate fast Fourier transform, and then balance disturbances coefficient.Comparisons of coefficient values obtained for the whole group and two selected participants were presented in order to explain how to interpret and use the coefficient. For better explanation of coefficient interpretation the most popular time domain stabilometric quantities and fast Fourier transform curves were presented as well.The balance disturbances coefficient makes it possible to quantitatively and objectively determine, on the basis of fast Fourier transform curves, the influence of the oscillating scenery on the tested person as well as show how the overall equilibrium of that person was disturbed.

The aim of the research was to determine the energy changes during the gait cycle for a group of healthy children and a group of patients with cerebral palsy, and to compare the value of energy expenditure (EE) with the determined values of the Gillette Gait Index (GGI) and the Gait Deviation Index (GDI).The study group consisted of 56 children with regular gait and 56 patients with diagnosed cerebral palsy (CP). The gait kinematics was determined by BTS Smart System. Based on the identified position of the body mass, the following parameters were determined: the potential energy, kinetic energy, and total energy. The values were standardized to 100% of the gait cycle. The values of the Gillette Gait Index (GGI) and the Gait Deviation Index (GDI) were calculated using the authors' own software.Values of potential, kinematic and mechanical energy changes and mean values of total energy (energy expenditure - EE) were calculated for a reference group and for patients with CP. The obtained results were standardized in relation to the body mass and stride length. Furthermore, the values of the Gillette Gait Index (GGI) and the Gait Deviation Index (GDI) were calculated. Statistical analysis of the obtained results was performed. The Spearman rank correlation coefficient was defined between the calculated GGI and GDI values and energy expenditure EE.Values of energy expenditure changes can be used as an objective comparative tool for gait results concerning children with various neurological and orthopaedic dysfunctions.

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.

The aim of the research was to formulate a new index enabling assessment of the overall pathology of the upper limb movement. It defines the difference between the pathological movement and a normal movement pattern.Methodology of determining the index is based on a mathematical algorithm for calculating the Gait Deviation Index which is based on advanced methods of image comparison. To calculate the ULMDI index, one must divide the analyzed movement into cycles appropriate to the nature of the movement (similarly in gait it is the gait cycle) and then determine kinematic quantities (courses of joint angles).A group of 23 healthy people (10 women: k1-k10 and 13 men: m1-m13) as the reference group and a group of 3 persons with mobility impairments (p1-p3) took part in the research. Time values of the angles of the joints on both upper limbs were registered and then ULMDI indexes were calculated.It has been shown that the developed ULMDI index allows to detect the deviations from the accepted norm in the performance of movements. The results showed that both the description of the motor dysfunction of examined person based on the diagnosis of the physician, a detailed analysis of kinematic waveforms received during the tests and the calculated values provide a coherent picture of the state of a human movement. The index analysis is less time-consuming for the doctor, and the comparison of the results at various stages of therapy gives an objective picture of the rehabilitation progress.

Limb physical movements disability is the result of illnesses or serious injuries, impaired execution of daily activities and limitations or even inability to perform working activity. Restoration of fitness in such cases is possible through rehabilitation that requires arduous repetition of appropriate exercises with participation of an experienced physiotherapist. Exercises using the robot to repeat movements would speed up the process of rehabilitation. The paper presents the concept of rehabilitation robot control system realizing a specified purpose.

Background This paper presents a case study of kinematic analysis of the modern dance movement known as the "stag jump". Detailed analysis of the kinematic structure of this movement as performed by the dancers, accompanied by measurements of impact forces during landing, will allow the authors to determine, in subsequent model-based research phases, the forces acting in knee joints of the lower landing limb. Material and Methods Two professional modern dancers participated in the study: a male and a female. The study consisted in recording the values of ground reaction and body motion, and then determining and analyzing kinematic parameters of performed movements. RESULTS The results of measurement of joint angles in the landing lower limb, pelvis, and foot position in relation to the ground, as well as the level of vertical components of ground reaction, provided insight into the loading response phase of the "stag jump". The measurements and obtained results show differences between the man and woman in ground reactions and kinematic quantities. CONCLUSIONS The results obtained during the research may be used in the development and teaching of dancing movements. Training sessions, carried out in the biomechanical laboratory, with active participation of dancing teachers, could form a basis for a prevention model of injuries and physical overloads occurring within this occupational group. Primary differences in the "stag jump" performance technique probably result from the different educational path the man and the woman went through. Language: en

The paper presents an analysis of the loads acting on lumbar spine during movement of sitting down and getting up from a chair. The study was conducted on a group of 30 people (parents of disabled children) complaining about chronic low back pain. Basing on kinematics, obtained during experiment from APAS system, simulations were performed in the Anybody Modeling System environment. The use of methods, mathematical modeling and static optimization, allowed to determine the magnitude of the loads acting on musculoskeletal system. The results of reactions in the L5-sacrum joint, the muscular forces of erector spinae and the transversus abdominis are significantly correlated with the kinematics of the movement.

The aim of this study was to analyze locomotor function of children with cerebral palsy based on changes in muscle length and to evaluate if the muscle length changes may be used as a diagnostic indicator. The study group consisted of 23 people with normal gait and 3 patients with cerebral palsy. Locomotor function tests were performed using the BTS Smart system, while the length of the muscles were determined using mathematical modeling methods with the help of Anybody Modeling System software. In this study the muscle group functioning in connection with the knee joint were analyzed. The results of muscle length changes for children with CP were compared to those of people with no evidence of impaired locomotor function, as well as to the values of GGI and GDI indicators and to kinematic parameters.

System of engineering support of upper limb diagnosis was developed and verified as a part of the research. Virtual Cave 3D, System VRTouchDevice and inertial motion analysis system MVNBiomech were used to build this system. In cooperation with the physiotherapist 2 applications were developed to motivate to do exercises during which kinematic parameters of the examined people were registered. The prepared system was positively verified by correlating waveforms angles in joints for a physiotherapist with the waveforms of people who exercise in the developed system.

This article deals with kinematic and kinetic conditions in volleyball attack and identifies loads in the shoulder joint. Joint angles and velocities of individual segments of upper limb were measured with the use of the motion capture system XSENS. Muscle forces and loads in skeletal system were calculated by means of mathematical model elaborated in AnyBody system. Spikes performed by players in the best and worst way were compared with each other. The relationships were found between reactions in shoulder joint and flexion/extension, abduction/adduction and rotation angles in the same joint and flexion/extension in the elbow joint. Reactions in shoulder joint varied from 591 N to 2001 N (in relation to body weight [BW] 83–328%).The analysis proved that hand velocity at the moment of the ball hit (which varied between 6.8 and 13.3 m s–1) influences on the value of reaction in joints, but positions of individual segments relative to each other are also crucial. It was also proved in objective way...

Defining the influence of parameters of visual disorders on ability of balancing turns out to be an important process in effective diagnostics. Current diagnostic methods relating mainly to determination of the coefficient of BRUTM (Balance Rehabilitation Unit Trade Mark) depend on lots of tests carried out in a disturbed environment created by Virtual Reality Technology. The aim of this study is to determine the effect of the frequency of visual disturbances on stabilographic values in the virtual reality environment.The study was carried out involving one research group in Virtual Cave. There were induced visual disturbances with different frequencies and with the change of frequency during measuring the position of the center of pressure (COP) in the test. Before each test the reference test was performed. All tests were performed with disorders in two different sceneries: closed and open scenery. All measurements were carried out on an immobile Zebris platform which enables determination of feet pressure distribution. From the measured values of the position of the COP Short Time Fourier Transform (STFT) was calculated.The results of calculation are shown in graphs. Their analysis showed that changing the parameters of disorder frequency in world created using Virtual Reality Technology affects stabilographic parameters. The intensity of these changes is also affected by applied research scenery.Conditions have been set out to carry out similar studies in order to obtain reliable results. The study is the first step in a project to develop a system for diagnosis and rehabilitation of human movement using Virtual Reality Technology.

A three-dimensional analysis of movement is more and more often applied to assess locomotive functions of patients with cerebral palsy (CP). For the past few years there has been a growing interest in gait index methods which enable the evaluation of the patient’s gait with the use of a single numerical value. This research aimed at the assessment of the gait of patients with CP at different stages of treatment on the basis of gait indices Gillette Gait Index (defined by Shutte) and Gait Deviation Index (definied by Schwartz and Rozumalski) as well as finding dependencies between the determined indices values. The studied group consisted of 56 healthy participants and 16 patients with cerebral palsy treated using botulinum toxin. On the grounds of the determined indexes, the improvement of gait was observed in the case of 75 % of patients with CP. Statistically significant differences were found between GGI and GDI values obtained in the initial investigation and after 6 months following the administration of botulinum (PRE and POST). There was a strong linear dependence observed between the GDI and GGI* (\(GGI^*=\ln (\sqrt{GGI})\)) values. No significant dependence was observed between the percentage indices of improvement determined on the basis of the GGI and GDI results obtained (in the PRE and POST examination).

Objective Recently the fast progress in the development of systems attending the three-dimensional gait evaluation is being observed. One of the indexes used to the analysis is Gillette Gait Index (GGI), complying 16 clinically meaningful kinematic and three-dimensional parameters. Methods The study was conducted with application of the three-dimensional system of gait analysis BTS Smart and carried by the team of pediatric neurologists, physiotherapists and engineers. Spatial-time parameters of gait and courses of angles of joint of lower limbs were determined on the basis of conducted research. Those parameters were used in estimation of Gillette Gait Index. The analyzed group consisted of ten CP patients treated with botulin toxin (three children with hemiparesis, seven with diparesis), intensively rehabilitated after the botulin treatment. The data were compared to four patients put on rehabilitation without the botulin treatment. The patients treated with botulin were evaluated three times: before the botulin administration, then three and six months after it. In the other patients' group the evaluation was conducted three months after rehabilitation start. The results of gait evaluation were compared to the gait pattern of the healthy children; the normal values were worked out by the authors. Results After the botulin treatment and rehabilitation the increase of the gait speed and frequency of steps were observed; the GGI decreased both after three and six months of observation. The locomotive function of the patients' improved in 70% of them. Conclusion The authors regard the results presented above as the pilot-study; the evaluation of the larger groups of children with cerebral palsy is conducted. In the authors' opinion the objective method of CP children gait evaluation may be the helpful tool for clinicians to optimize the way of CP children treatment. Study realized as a part of the DEC-2011/01/B/NZ7/02695 project, financed by National Science Centre.

The paper presents the results of strength calculations of the structural form of a prototype device for the rehabilitation of the lower limbs. Developed structural form designed in Inventor has been imported into Ansys Workbench environment in which the was made the discretization of the geometry model and boundary conditions were set. The calculations were performed using the software package of finite element method ANSYS Workbench.

A reduced mobility resulting from diseases or injuries frequently leads to elimination of the patient from active life and makes it impossible for them to continue employment. The rehabilitation exercises aimed at improving motor skills usually involves the arduous repetition of the same necessary exercises with the active participation of an experienced physical therapist. The aim of this paper was to present the control system of a rehabilitation robot that will allow us to reduce the physical therapist participation and will limit their physical effort, at the same time allowing them to better assess the progress of physical therapy delivered. The assessment of the adopted assumptions was performed using a prototype robot-the LEG-100 lower extremity exoskeleton whose control system was based on the assumptions presented in this paper.

The article concerns research into gait kinematics of people after stroke. The comparative analyses of angle courses and gait parameters were carried out. Results obtained for people with left and right sided paresis were compared with each other.

Limb disability, which in many cases results from disease or injury, impairs everyday actions and limits job opportunities. Treatment consists of physical therapy that requires laborious repetition of recommended motions with the help of an experienced physiotherapist. Robot-aided exercises for repeatable rehabilitation motions would allow speeding up the rehabilitation process and reduce its costs. This work presents a concept of a control system for a rehabilitation robot constructed for this aim. The solution has been verified with the prototype robot ARM-100 for upper limb rehabilitation with the control system based on the assumptions discussed in this paper.

The paper presents the results of kinematic analysis of the prototype of rehabilitation device for human upper limb. The aim of these measurements was to assess possibility to execute PNF movements in upper limb joints and correctness of functioning of control algorithms responsible for reproducing of assigned movements The measuring site consisted of a set of 4 digital cameras, computer workstation, a set of markers, calibrating dice and light sources. Measurements were carried out for simple and complex movements. First a man forced a motion sequence, and then the device had to repeat it. Measurements revealed necessity of changes in constructions due to unacceptable positioning inaccuracy. Exemplary results before and after these changes are presented in the paper.

The paper presents the results of kinematic analysis of therapeutic movements of the upper limb, according to PNF method recommendations. Real trajectories of upper limb movements were recorded using the photogrammetric method. The measuring site consisted of a set of 8 digital cameras, two computer workstations, a set of markers, calibrating dice and light sources. On the basis of the recorded images and calculations performed with the use of specialized software, model trajectories of the analyzed movements and values of relative angular translocations and angular velocity in individual joints of the limb were defined.