The Influence of Training Load on Musculoskeletal Injury Risk Variables, Objective Fatigue, Subjective Well-Being, and Performance in Baseball Athletes

Baseball’s unique sport demands lead to a high prevalence of time-loss injuries. Previously identified injury risk factors in baseball include decreased shoulder strength, decreased shoulder range of motion, increased self-reported fatigue, excessive participation and limited rest and recovery. Sport participation may be monitored via training loads, which longitudinally track the physical work performed and the perception of difficulty of activity to identify when excessive participation occurs. Excessively high training loads and large changes to training loads influence injury risk in field sports, but there is no evidence in baseball players to indicate if training loads influence changes to musculoskeletal variables linked to injury. The purpose of this research study was to determine the influence of training load on musculoskeletal injury risk variables, objective fatigue measures, subjective well-being measures, and baseball performance. Baseball players were assessed every 4 weeks over the course of the fall semester for musculoskeletal injury risk variables, and objective fatigue measures. Participants provided daily reports of baseball-specific training load and subjective well-being variables. Baseball performance variables, average weekly fastball speed, weekly average fastball spin, and weekly average exit velocity were collected at each competition during the fall season. The results from this study indicate that baseball specific training load has significant effects on subjective well-being measures, including weekly average readiness, weekly average stress, and weekly average soreness. Baseball-specific training load had a mild effect on very few musculoskeletal injury risk variables and objective fatigue measures, including the functional reach tests and grip strength. There was almost no effect of baseball-specific training load on shoulder rotation range of motion, shoulder strength, single leg bridge test, jump height, jump power, or any baseball performance variable. Baseball-specific training loads influence variables that may play a role in illness and injury in athletes, so utilizing training loads to monitor baseball participation may be useful to determine when baseball players are at risk for injury and illness. Future research should continue to investigate baseball-specific training loads to understand how they specifically influence injury risk in baseball players.Doctor of Philosoph

MODELLING OF NON-ROAD TRANSIENT CYCLE

The paper describes the modeling of NRTC (Non-Road Transient Cycle) test procedure based on previously measured characteristics of fuel consumption, carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons (HC), nitrogen oxides (NOx) and particulates (PM) production. It makes possible to compare the current technical condition of an internal combustion engine of an agricultural tractor with its previous state or other tractor’s engine. Based on measured characteristics, it is also possible to model any other cycle without further measurements (NRSC test procedure, cycle for specific conditions – mountain tractor, etc.). The result may thus contribute to improving the environment by reducing the production of harmful substances emitted into the air and save money due to reduced fuel consumption

Effect of rake angle and cutting speed on energy demands of mulcher with vertical axis of rotation

ArticleThe contribution deals with the reduction of agriculture energy demands. For maintenance and treatment of permanent grassland areas, areas left fallow and put to rest the mulching in combination with other workflows (mowing, grazing) is advantageous procedure. As conventional impact grass cutting and chopping is energy demanding procedure, it is proper to reduce the energy demands of such device. In the paper the effect of shape of cutting tool, particularly the rake angle, on energy demands of mulcher with vertical axis of rotation is studied. The effect of cutting speed on energy demands is also verified. The measurement was performed using mulcher MZ 6000 made by Bednar FMT Ltd. with working width of 6 m and three rotors. During the measurement the test rides using the cutting tools with different rake angle and cutting speeds of 105m s-1 , 89 m s-1 and 79 m s-1 were performed. The rake angle of cutting tools were chosen 0°, 15° and 25°. The test area was pasture with permanent grassland. During the measurement the torque and power, transferred through PTO to the machine, fuel consumption and GPS coordinates were measured. From each test ride the samples of grass matter were taken in order to determine the yield and moisture content. It was found that increase of the rake angle up to 25° and decrease of the cutting speed resulted in decrease of the power requirement of the mulcher

Implementing of security measures according to ISMS for elementary school

Diplomová práce se zabývá zavedením bezpečnostních opatření pro základní školu. Práce je rozdělena na tři hlavní části. V první části diplomové práce jsou zpracovány základní teoretické pojmy z oblasti informační bezpečnosti a legislativní náležitosti potřebné pro pochopení dané problematiky. Druhá část diplomové práce popisuje stávající stav na základní škole. Poslední praktická část obsahuje samotný návrh bezpečnostních opatření a doporučení.The diploma thesis deals with introduction of security measures for primary and elementary school. The thesis is devided into three main parts. The first part deals with basic theoretical concepts of information security and legislative elements needed for understanding the issue. The second part desrcibes the current state for primary and elementary school. The last practical part includes proposal of security measures and recommendations.

Recovery of Infraspinatus Cross Sectional Area, Echo Intensity, and Glenohumeral Range of Motion Following Bouts of Overhand Pitching

Previous work demonstrates that eccentric load associated with baseball pitching results in swelling of the infraspinatus, with accompanying changes in glenohumeral flexibility. Infraspinatus swelling and flexibility measurements provide markers for both trauma that results from pitching and a means to monitor recovery following pitching. The purpose of this study was to longitudinally track changes in measures of infraspinatus swelling (cross-sectional area and echo intensity) and humeral rotation flexibility daily, up to 7 days following a bout of pitching. Ten Division 1 baseball pitchers volunteered as participants. One general linear model was run to analyze change in scores per dependent variable per limb (twelve in total). Infraspinatus cross-sectional area increased one day following pitching and internal rotation decreased for three days after pitching. Baseball pitchers cause damage that can last up to 3 days. Recovery must occur to pitch on subsequent days so arms may return to baseline before reapplying stress.Master of Art

The operational parameters and emissions of portable generator after long-term operation on n-butanol

ArticleThe utilization of biofuels in spark ignition and compression ignition engines is the trend of the recent time. The great expectations are inserted into n - butanol as a fuel, especially for spark ignition engines. The short time use of n - butanol in the SI (spark ignition) combustion engine does not make a big problem (start of the cold engine, change of the air - fuel ratio). The purpose of this contribution is the effect of long - term use of n - butanol as a fuel for SI engine. For this purpose the small portable generator was used. The harmful emissions, fuel consumption and power of the generator was measured then the generator was operated for 300 hours on 100% n - butanol with 80% of nominal load and the measurement was repeated. The g enerator was loaded with adjustable electrical resistance. As a reference fuel the petrol BA 95 with no bio - component was used. During the operation on n - butanol no technical problems occurred with the generator. After 300 hours of operation on n - butanol t he performance parameters slightly decreased with little impact on production of harmful emissions components

Influence of shape of cutting tool on pressure conditions in workspace of mulcher with vertical axis of rotation

ArticleNowadays there is laid great insistence on work efficiency improvement. This effort also affects the construction of mowers such as mulchers. Mulching with a vertical axis of rotation is very energy demanding work operation mainly, due to high energy losses. These energy losses, but also the quality of work, are influenced by the airflow and associated conditions of pressure inside the workspace of mulcher. Airflow in the workspace ensures repetitious contact of the truncated forage crops with the cutting edge tool and thus ensures crushing of aboveground parts of plants. The paper deals with the influence of the cutting tool shape on the mulcher’s inside workspace pressure conditions with the vertical axis of rotation. The influence of the trailing edge angle and rake angle on the pressure profile in the mulcher’s workspace with dependence on the rotor speed was examined. Measurements were performed on a laboratory single rotor mulcher model. It was found that in the mulcher’s workspace the vacuum is formed by virtue of the rotary movement of the cutting tools wherein the vacuum increases with rotor speed. The maximum measured vacuum was about 2.4 kPa and from the centre of the rotor towards its circumference almost linearly decreases. Furthermore, it was found that with decreasing trailing edge angle and with increasing rake angle the maximum vacuum decreases. When reducing the angle of the trailing edge from 45° to 25° led to reduction of vacuum of about 0.3 kPa (12.6%)

Comparison of mechanical and electric drive of mulcher

ArticleThe contribution is focused on comparison of mechanical and electric drive of mulcher with vertical axis of rotation by means of mathematical model. The mulcher has working width of 6 m and it is usually aggregated with tractor of minimal power of 150 kW. On the test plot the torque and power transferred trough the tractor PTO, fuel consumption and the production of gaseous emissions components were monitored. This field measurement served as a basis for modelling as well as measured complete characteristics of the combustion engine of the tractor John Deere 7930. As a main base for the modelling the record of real operation of the tractor with mulcher was used. Then, in the software product MathCad the operation of the tractor with mechanical and electrical drive of the mulcher was modelled. In the case of the electrical drive of the mulcher the tractor with internal combustion engine, connected to generator was taken into consideration. Due to overall lower efficiency of the electrical drive with generator, worse values of the fuel consumption and emissions production in comparison with mechanical drive were reached in case of electric drive. At hypothetical use of batteries (100% electro-powered tractor) and when the energy mix at Czech Republic is taken into consideration, it is possible to reach the quarter values of emissions production in comparison with combustion engine

Effect of long-term operation of combustion engine running on n-butanol – rapeseed oil – diesel fuel blend

ArticleThe short time use of biofuels in compression ignition engines is being studied by many authors. However, in many cases the real long–term operation of the engine on biofuels may cause problems. The article deals with the operation parameters of the combustion engine, fuelled by n-butanol – rapeseed oil – diesel fuel blend, during 70 hours operation in total. Two brand new diesel power generators Kipor KDE 6500 with output power of 4.6 kW were used for certain testing. The first generator was operated on 100% diesel fuel and it was used as a reference and the second generator was operated on experimental fuel containing 10% n-butanol – 20% rapeseed oil – 70% diesel fuel blend. The generators were equipped with single cylinder compression ignition engine Kipor KM 186 with the rated power of 5.7 kW. For the first 10 operating hours approx. 40% load was applied. Then, the generators worked for another 60 operating hours with approx. 70% load. The harmful emissions, smoke, fuel consumption and the amount of produced particles were also measured after 10 hours run-in period and then after another 60 hours of operation. Consequently, the results were compared. Measurements were carried out at gradually increasing electric power output, approx. 14%, 28%, 42%, 56%, 68%, 82% and 95% (in results can be found in Watts). Emission analyser and opacimeter BrainBee and Engine Exhaust Particle Sizer TSI were used for the measurements. The results showed increased production of emission of the engine running on fuel blend after 70 hours of operation. On the other hand, engine which operated on standard diesel reached lower fuel consumption. After 70 hours the blended fuel tended to produce more particles in comparison with diesel fuel

Combustion characteristics of compression ignition engine operating on rapeseed oil-diesel fuel blends

ArticleThe effect of biofuels on the operational parameters of the combustion engines, such as performance parameters or emission production, are monitored often. These changes are, however, based on the effect of biofuels on the course of combustion pressure inside the combustion chamber. The contribution deals with the effect of rapeseed oil-diesel fuel blends on the combustion characteristics of turbocharged compression ignition engine. The course of cylinder pressure was monitored and analysed and heat release rate was calculated. The brake specific fuel consumption, indicated and brake thermal efficiency were calculated and evaluated, in-cylinder temperature and ignition delay were also evaluated. As a test fuels a 5% and 20% concentrations of rapeseed oil in diesel fuel were selected while 100% diesel fuel was used as a reference. Turbocharged CI engine Zetor 1204 located in the tractor Zetor Forterra 8642 was used for measurement. During measurement the rotation speed of the engine was kept constant at approx. 1950 min-1 and the load of the engine was selected at approx. 20, 60, 80 and 100%. The results showed decreased cylinder peak pressure, decreased intensity of heat release rate and earlier end of combustion in all tested loads for both tested fuel blends in comparison with diesel fuel, while the lowest peak cylinder pressure was reached using fuel with 5% rapeseed oil. Fuel with 5% rapeseed oil also showed highest indicated efficiency. Ignition delay was found shorter with both of the blended fuels in comparison with diesel fuel