INFLUENCE OF A 6-WEEK MIXED BALLISTIC-PLYOMETRIC TRAINING ON THE LEVEL OF SELECTED STRENGTH AND SPEED INDICES OF THE LOWER LIMBS IN YOUNG FOOTBALL PLAYERS

The development of muscle power should be taken into account in soccer training. The aim of this study was to evaluate the influence of a 6-week of mixed power training on the level of the motor skills of the lower limbs of young soccer players. The training was conducted during the starting period. The study included twelve 16-18-year-old players who regularly participated in specific soccer trainings and played in regional competitions. Their basic anthropometric features were measured. The assessment of the power of the lower limbs was carried out using two jump tests: CMJ and SJ. The maximum anaerobic power was calculated and was expressed in relation to body weight and lean body mass. In addition, Drop Jump tests were performed from three different heights on the basis of which RSI reactive strength index were calculated. On completion of the training program an increase in the level of the results of all the tests was observed: SJ (cm) (cohen's d: 0.43), CMJ (cm) (cohen's d: 0.33), SJPmax (W/kg) (cohen's d: 0.43), CMJPmax (W/kg) (cohen's d: 0.30), SJPmax (W/LBMkg) (cohen's d): 0,57), CMJPmax (W/LBMkg) (cohen's d: 0,44), RSI 0,2 (cohen's d: 0,59), RSI 0,3 (cohen's d: 0,45), RSI 0,4 (cohen's d: 0,58). An additional six-week ballistic-plyometric training program, used as a supplement to the basic training plan during the start period, resulted in an increase in the motor skills of the lower limbs of young soccer players. The application of combined ballistic and plyometric training methods helps to improve the strength and speed potential of young soccer players.

ANTHROPOMETRIC CHARACTERISTICS AND ANAEROBIC POWER OF LOWER LIMBS AND THEIR RELATIONSHIPS WITH RACE TIME IN FEMALE SPEED CLIMBERS

Previous research indicates that high results in speed climbing are determined by a high level of explosive strength and muscle power in the lower limbs. However, a literature review shows that no studies have analysed women practicing this climbing discipline. Therefore, the main goal of the study was to assess the level of development of physique and the level of explosive strength and muscle power of the lower limbs of female speed climbers at a representative level. Furthermore, an attempt was made to analyse the relationships between the variables studied and race time in female speed climbers.The study included 5 female players (speed climbers) who were members of the national team in 2016. The measurements were made during the Polish National Team Camp.  The analysis was based on the results of the fastest races expressed in seconds. The measurements and indices computed in the study included body height, body weight, lean body mass, BMI and ponderal index. The assessment of the power of the lower limbs was carried out using two jump tests: CMJ with arm swing and CMJ. Power was expressed relative to body weight and to lean body mass.The highest relationships with race time were recorded for body height (r = 0.94, p 0.05), body weight (r = 0.96, p 0.01) and lean body mass (LBM) ( r = 0.98, p 0.01). Strong but statistically insignificant relationships were recorded between race time and power indicators of the lower limbs (correlations above r = -0.66).In female speed climbing, race time can be determined by the level of physique. Smaller body size can allow female climbers to perform faster and achieve better times in speed climbing. It can be suggested that in female speed climbing, a high level of maximum alactic anaerobic capacity of the lower limbs is an important factor that affects race time. The results of our own research suggest that in female speed climbing, specific body characteristics may to a greater extent determine the race time compared to anaerobic maximum power of the lower limbs

Proportional flow controller model in Matlab-Simulink

This paper presents a method of creating a model of proportional flow control in Matlab- Simulink. A mathematical model of the controller and power supply system where the regulator is running. Model in Simulink is a block diagram. The individual blocks represent components of the hydraulic system

Automatic Taxi Directional Control System of Carrier-based Aircraft

This paper solves the problem of automatic taxiing direction control of carrier-based aircraft. On modern aircraft carriers, taxiing aircraft either propel themselves using their own engines or are towed by specialised tugs, which requires dedicated personnel and assets. The automatization of this process would simultaneously increase aircraft flow and decrease the number of personnel and assets required. The key challenge in the automatization of this type of process is the development of an automatic control system capable of performing the requisite tasks, which our researchers managed to do. First, the specific conditions of taxiing on-board carriers were analysed and modelled. The model of a fixed-wing aircraft best suited to this purpose was identified and the proper method of automatic control – ADRC – chosen. The algorithm used in the method to facilitate effective direction control of a taxiing aircraft was formulated and extensively tested. The results of automatic taxiing simulation for F/A-18 aircraft have been presented. The conclusion is that the ADRC type control algorithm can ensure effective automatic control of taxiing aircraft

VALUE OF SPEED CAPABILITIES IN YOUTH SPEED CLIMBING AT HIGH SPORTS LEVEL

Current research on speed climbing at the senior level shows that speed capabilities are a significant factor determining climbing time. The main purpose of our research was to evaluate the level of speed capabilities among young speed climbers and to examine the relationship between the level of speed capabilities and the results achieved during an international competition. The subjects of the research were girls and boys in the following age categories: Female Youth A (age=16.6), Female Youth B (age=14.5 years), Male Youth A (age=16.87 years) and Male Youth B (age=14.8 years). Measurements of somatic features were included: body height, body weight, percentage of fat tissue and BMI. Speed capabilities were measured with Wingate Test. The significance test of differences showed no significant differentiation within climbing times between the groups of girls and the groups of boys. A strong correlation between climbing time and relative peak power was noticed in the Female Youth B group. The correlation between peak power and climbing time was lower in the other groups. Research showed that in speed climbing, as career progresses, it is importance of other factors rather than speed capabilities that may increase. It can be assumed that with an increase in training experience, motor skills become more essential.

A New Analyzer Based on Pellistor Sensor with Neural Network Data Postprocessing for Measurement of Hydrocarbons in Lower Explosive Limit Range

We present the results of a first stage of development work on a new type of analyzer for hydrogen and C1–C3 hydrocarbons concentration measurements in the lower explosive limit range, based on single pellistor sensor with artificial neural network data postprocessing

PREDICTING PERFORMANCE IN SPEED CLIMBING: ACCURACY OF THE FORCE-VELOCITY TEST ON A CYCLE ERGOMETER

The present study examined the validity of the force-velocity (F-V) mechanical parameters of the lower limbs as a predictors of the competitive performance in junior male speed climbing. The second aim was to evaluate F-V characteristics in competitive speed climbers in the junior male category. Ten junior male speed climbers (age: 18±0.5 years; BH: 174.7±4.5 cm; BW: 66.4±6.6 kg; with mean best climbing time from the competition BCT: 7.29±0.66 s) were participants in the research. All they were participants in the Youth European Cup in speed climbing. F-V characteristics were measured using a cycle ergometer test according to the Vandewalle’s protocol. To evaluate of the validity between BCT (criterion) and mechanical parameters (practical measures) from F-V test a standard error of the estimate (expressed as a raw and standardized typical error, TE) and correlation coefficients (rx,y) were used. Moreover, the validity of BCT as a potentially predictor of final competition rank (as a criterion for BCT) was evaluated. Additionally the mean value and standard deviation were calculated for all measured variables. Validity of the BCT as a competition place predictor was largely overestimated (TE=0.73 and rx,y=0.81, p p≤0.05). Accuracy of the BCT prediction for somatic and mechanical variables were very largely error biased. The standardized values of TE for these variables were: 1.93÷7.25. The rx,y were in the range of -0.18 to -0.46. The level of the mechanical variables from the F-V cycle ergometer as a predictors of the BCT in speed climbing may be largely error biased. Application of the cycle ergometer F-V test of prediction BCT values in speed climbing may have low practical value. Moreover, BCT variable may be a poor predictor of the final competition result. Coaches should take these suggestions into account during preparations to speed climbing competitions.

Advantages and Disadvantages of Various Uncertainty Assessment Methods in Material and Technological Predictive Models

This article reviews known approaches to determining the uncertainty of predictive models: probabilistic analytical, probabilistic simulation and fuzzy. The main elements determining the specificity of a given approach are shown. The advantages and disadvantages are compared. Finally, the application guidelines are listed

Environmental: choices vs. COVID-19 pandemic fear - plastic governance re-assesment

Alarming plastic production growth worldwide reinforces the public debate about the prevailing environmental crisis, whereby single-use-plastic (SUP) items are considered as by far the most harmful to the environment and public health. Accordingly, European environmental policy aims at eliminating SUP. Recently, we presented a model of plastic governance that derives from a circular economy approach identifying and taking into consideration perspectives of different actors in the plastic governance, such as producers, wholesalers, shop keepers, consumers, citizen scientists, and academia. Our results illustrate that the vast majority of stakeholders cared for the natural environment and understood the need to phase out SUP from the global economy. We proposed that a knowledge brokerage, undertaken by scientists via means of citizen science, as the most effective method to implement elimination policy, as it provides stakeholders with knowledge on why and how to handle SUP issues. However, at the time of the global COVID-19 pandemic, a plastic governance model required a re-assessment. The perceived role of SUP has changed, as it reflects the health emergency. Namely, due to the health safety reasons stakeholders and consumers are requesting even more SUP than previously. Following up on our data gathered prior to the pandemic, we suggest that under the new circumstances health concerns outweigh the environmental concerns being determined by a shift in the value hierarchization. The paper discusses preliminary results