The ability to reach a high running velocity over a short distance is essential to a high playing performance in team games. The aim of this study was to determine the relationship between running time over a 10-meter section of a 30-meter sprint along a straight line and changes in the angle and angular velocity that were observed in the ankle, knee, and hip joints. The possible presence may help to optimize motion efficiency during acceleration sprint phase. Eighteen girls involved in team sports were examined in the study. The Fusion Smart Speed System was employed for running time measurements. The kinematic data were recorded using the Noraxon MyoMotion system. Statistically significant relationships were found between running time over a 10-meter section and the kinematic variables of hip and ankle joints. An excessively large flexion in hip joints might have an unfavorable effect on running time during the acceleration phase. Furthermore, in order to minimize running time during the acceleration phase, stride should be maintained along a line (a straight line) rather than from side to side. It is also necessary to ensure an adequate range of motion in the hip and ankle joints with respect to the sagittal axis.

Ankle arthrodesis with the Ilizarov method is an accepted form of treatment of advanced degenerative changes of the ankle joint. Incorrect balance and load distribution on the lower limbs may result in pain and dysfunction. The aim of the study was to assess the change of balance and load distribution in lower extremities in patients before and after ankle arthrodesis with the Ilizarov method. Between 2013 and 2016, ankle arthrodesis using the Ilizarov method was performed on 21 patients. The evaluation of balance and percentage of load in each lower limb was performed before the surgery and during the follow-ups. The evaluation was performed using a Zebris pedobarographic platform. Before the surgery, the patients exhibited an average load of 41.9% of body weight in the affected limb, whereas the load in the healthy limb was 58.1%. The difference was statistically significant (p = 0,000031). In two years follow-up, the average load in the treated limbs was 48.19%, whereas the healthy limbs were subjected to an average load of 51.81%. In preoperative tests, the average path length of the center of gravity was 161.55 cm; postoperatively, the average path length of the center of gravity was 129.7 cm (p = 0.00003206). Preoperatively, the average area of the center of gravity was 18.85 cm2; it decreased to 6.19 cm2 (p = 0.000032) postoperatively. Arthrodesis of the ankle with the Ilizarov method improved the statics of the musculoskeletal system by improving the distribution of loads in the lower limbs as well as balance. However, it failed to restore the parameters of a healthy person. Advanced degenerative changes of the ankle disturb the biomechanics of the entire lower limb.

This paper presents the results of investigations on novel pressure measurement methods to be for used in the project "Polish Artificial Heart". The investigations concerned possible pressure sensors for noninvasive blood pressure measurements in selected points around the pneumatic ventricular assist device (POLVAD). The fiber pressure sensor and the possibility of pressure measurements with piezofoils were tested. The paper includes preliminary results and development plans.

BackgroundA number of various techniques were proposed to stabilized ankle arthrodesis, among them external and internal fixation. Appropriate balance and adequate distribution of lower limb loads determine normal biomechanics of the locomotor system. We hypothesized that various techniques used to stabilize ankle arthrodesis may exert different effects on (1) balance and (2) distribution of lower limb loads.MethodsRetrospective analysis included 47 patients who underwent ankle arthrodesis with external stabilization with Ilizarov fixator (group 1, n = 21) or internal stabilization with screws (group 2, n = 26) between 2007 and 2015. Balance and distribution of lower limb loads were determined with a pedobarographic platform.ResultsIn group 1, average load of the operated and non-operated limb amounted to 48.8% and 51.2%, respectively, and in group subjected to internal stabilization to 48.4% and 51.6%, respectively. Neither the intragroup nor the intergroup differences in the distribution of lower limb loads were statistically significant. Mean length of the center of gravity (COG) path was 137.9 cm for group 1 and 134 cm for group 2, and mean COG area amounted to 7.41 cm2 and 6.16 cm2, respectively. The latter intergroup difference was statistically significant.ConclusionsBalance after ankle arthrodesis with Ilizarov fixation is worse than after the same procedure with internal stabilization. Despite correction of ankle deformity, musculoskeletal biomechanics still remains impaired. While ankle fusion with either Ilizarov or internal fixation provide appropriate distribution of lower limb loads, none of these procedures normalize patients’ balance.

Background. Severe osteoarthritis (OA) of the ankle joint constitutes an important social problem. Objectives. We used (1) the GRIMBY scale, (2) the LOWER LIMB Activity scale, (3) the UCLA (University of California Los Angeles) activity scale, (4) the VAS (visual analogue scale) ACTIVITY scale, and (5) the FAAM (foot and ankle ability measure) SPORT scale to verify whether the type of ankle joint arthrodesis stabilization affected sports and physical activity levels. Material and methods. We carried out a prospective clinical study of 47 patients who had undergone ankle arthrodesis with Ilizarov external fixator stabilization (Group 1, n = 21) or internal stabilization with screws (Group 2, n = 26) at Orthopaedic Clinic at the Wroclaw Medical University, Poland, from 2007 to 2015. Sports and physical activity levels were measured by (1) the GRIMBY scale, (2) the LOWER LIMB Activity scale, (3) the UCLA activity scale, (4) the VAS ACTIVITY scale, and (5) the FAAM SPORT scale. Results. A comparison between the average results of Group 1 and Group 2 on the LOWER LIMB Activity scale and the GRIMBY scale before and after surgery revealed no significant differences. In Group 1, the mean scores on the VAS ACTIVITY scale and the UCLA activity scale after treatment were higher than in Group 2. In Group 1, the mean outcome in the SPORT FAAM scale after treatment was 40; in Group 2 it was 30.06. Conclusions. Ilizarov fixation of ankle arthrodesis is associated with better scores on the FAAM SPORT, UCLA activity and VAS ACTIVITY scales after treatment than internal fixation. The scores on the GRIMBY scale and the UCLA activity scale were significantly higher after treatment than before treatment in both groups. In this study, ankle fusion with Ilizarov fixation and internal fixation was found to be effective in the treatment of ankle arthritis. The levels of sport and physical activity were satisfactory in both groups, but the outcomes after fixation with the Ilizarov apparatus were better than after internal stabilization.

The following paper introduces the problem of noninvasive pressure measurements in Polish artificial heart prosthesis. The pressure sensor is proposed and introduced, and preliminary tests are shown. The paper deals with the proposed sensing elements, requirement noninvasive solution and preliminary tests of polyurethane membrane transmission. The paper includes also experimental results of a fiber pressure sensor introducing noninvasive pressure measurements with pressure transmission through a polyurethane tube wall.

Abstract. The following paper presents researches concerning a noninvasive real-time blood volume measurement system applied in POLVAD prosthesis. The system is based on the acoustic Helmholtz resonator principle. The basis of the measurement method, followed by the preliminary tests of the possibility of incorporating the Helmholtz resonance idea into the POLVAD prosthesis is shown. The paper includes the actual measurement system construction and test results, both static and dynamic obtained at the Foundation for Cardiac Surgery Development in Zabrze, Poland. Conclusions and future plans are presented too.

Abstract-Due to the sensitivity of their physical properties to selected gases, graphite oxide (GrO) and reduced graphene oxide (RGO) can be used in optical gas sensors. The sensor properties of GrO and RGO depend significantly on the technology used for their production. In this paper the effects of oxidation and reduction processes on graphite physicochemical properties were presented.In many production processes, but also in environmental monitoring, an important problem is the detection of selected gases with adequate selectivity and sensitivity. Recently, much attention has been paid to the development of optical gas sensors, acting both on the basis of optical absorption and the phenomenon of propagation of modes in optical planar structures. It is important that the detection of selected gases should be unambiguous and at a low level of their concentration. Attention should also be paid to the response time of sensors (time of gas detection), which must be as short as possible. The metrological properties of optical gas sensor structures depend mainly on gas sensing layers. In the literature concerning gaseous sensors much attention is devoted to sensors based on graphene, graphite oxide (GrO) and reduced graphene oxide (RGO) [1][2][3]. There are many different methods of production [4-8] graphene based materials, which undoubtedly affects their structural properties. Our earlier studies [9][10] have shown that the sensor properties of graphene based materials significantly depend on the technology used for their production. In the present paper, the effects were investigated of oxidation and reduction processes on graphite physicochemical properties.The research work presented in this paper was designed to describe changes which take place in graphite after its oxidation and reduction. In order to clarify the description, the product obtained in an oxidation process will be referred as graphite oxide and denoted as GrO while the product obtained in a reduction process will be referred as graphite oxide and denoted as RGO. The * E-mail: sabina.drewniak@polsl.pl oxidation process is intended to incorporate the functional groups containing oxygen, e.g. carbonyl, carboxyl, hydroxyl and epoxy between the planes of graphene. The oxidation process was realized using Hummer's method, the reduction process was realized using a temperature of approximately 900 o C and inert conditions [11]. During the reduction process, the number of additional oxygen and hydrogen groups in GrO decreases, giving the RGO structure. The research presented in this paper was conducted using a sample of graphene flakes. Graphite is characterized as an ordered crystallographic structure and has a high content of mineral substance (at 9.7%). Preparation of graphite oxide:Commercial flake graphite powder (90µm), supplied by Signograf was oxidized by a modified Hummer method [12]. Concentrated H 2 SO 4 (95-97%) was used as an acid and KMnO 4 and NaNO 3. A graphite sample (1g) with a particle size <20μm was mixed with the acid and placed in...