Turn Speed Research Articles

Analysis and study of maximum allowable turning speed for civil aircraft

The maximum allowable turning speed of an aircraft is a critical factor affecting the safety of civil aviation. Evaluating the maximum permissible taxiing turn speed for civil aircraft is an essential aspect of aircraft design. To ensure that the aircraft does not experience unbalanced forces leading to a lateral rollover due to excessive taxiing speed, an engineering estimation method is employed to study the maximum permissible taxiing turn speed for civil aircraft. This method begins with certain assumptions and calculation scenarios, followed by the derivation of a calculation model based on the analysis of aircraft forces. Lastly, a case study of a specific aircraft’s maximum taxiing turn speed is conducted in conjunction with practical engineering considerations. The study reveals that as crosswind forces on civil aircraft increase, the maximum turning speed decreases. Moreover, for lighter aircraft with a forward center of gravity, the risk of lateral rollovers is higher. These findings underscore the engineering applicability of the estimation method.

Driving tetracycline hydrochloride degradation and concomitant hydrogen peroxide photosynthesis in a neutral environment over sulphur and oxygen codoped carbon nitride

The investigation of an artificial photosynthesis system for contaminant treatment and consecutive hydrogen peroxide formation is imperative but challenging, whereas the conversion efficiency is relatively low and far away from the demand for social development. Herein, oxygen and sulphur were collectively introduced into carbon nitride nanosheets (OSCN), together with sufficient edge and basal plane active sites. The as-synthesized sample could achieve a degradation efficiency of 84% for 100 mg/L tetracycline hydrochloride, together with simultaneous hydrogen peroxide production of 366 μmol g−1 h−1 under environmentally friendly neutral conditions. Intriguingly, the addition of tetracycline hydrochloride can accelerate hydrogen peroxide generation, which thus in turn speed up tetracycline hydrochloride degradation. It was revealed that the optimized electronic structure, promoted light-harvesting, and enhanced charge carriers separation capacity are conducive for the synchronous oxygen reduction and contaminant oxidation procedure in large measure. Furthermore, the degradation and hydrogen peroxide generation can be maintained even after 15 cycles, demonstrating the stability of OSCN and its possibility for practical applications. The degradation pathway and in-deep reaction mechanism are carried out accordingly. Additionally, such a synchronously promoted reaction can be extended to some other pollutants, like phenol and 2,4-dichlorophenol. This interesting work provides a novel strategy for pollutants removal and concurrent hydrogen peroxide generation.

PENGARUH VARIASI KECEPATAN PUTAR DAN DIAMETER PIN TOOLS TERHADAP KUAT GESER DAN STRUKTUR MAKRO SAMBUNGAN FRICTION STIR WELDING DISSIMILAR HIGH DENSITY POLYETHYLENE-POLYPROPYLENE

The purpose of this study is to find out the effect of pin tool turn speed and pin tool diameter on strong shear and macro structure on the friction stir welding dissimilar high-density polyethylene and polypropylene sheets. Variations in welding process parameters used in this study were: rotary speed of 980, 1560, 2360 rpm, and pin tool diameter of 4 and 5 mm. The shape of the cylinder pin, the feeding speed of 11 mm/min, and the plunge depth of 7.8 mm were maintained constant. The results showed that the highest shear strength value was obtained on the connection with a rotary speed of 1560 rpm and a pin tool diameter of 5 mm 4.8 N / mm2 or 23.71% of the tensile strength of raw material high density polyethylene. Observations of macro structures show that the pin tool diameter 5 mm has only slight defects in the stir zone.

Biological sex-related differences in whole-body coordination during standing turns in healthy young adults

Biological sexes (male and female) have been reported to influence postural control and balance due to differences in musculoskeletal structures, hormonal factors, and neuromuscular control. These factors can contribute to the turning performance, potentially leading to an increased incidence of falls, particularly during turning. Therefore, this study aimed to explore the whole-body coordination and stepping characteristics and during standing turns in healthy adults to determine the effects of biological sex and turn speed. Fifty participants (25 males and 25 females) completed 180° standing turns on level ground. Inertial Measurement Units (XSENS) were used to measure whole-body movement turning kinematics and stepping characteristics. Moreover, clinical outcome of dynamic balance was measured by the Timed Up and Go (TUG). Participants were randomly tasked to turn at three speeds; fast, moderate, or slow to the left and right sides. Mann–Whitney U tests were used to compare the independent variables between male and females, and Friedman tests with Dunn’s tests for pairwise comparisons were used to compare between the three turning speeds within the two groups. The results demonstrated that significant differences were seen between males and females during fast turning for the leading foot onset (p = 0.048) and in the slow speed for the total step (p = 0.033), showing that these were greater in female with an increase in turn speed. In addition, significant differences were seen only in the males when comparing different speeds in the trailing foot onset latency (p = 0.035), step size (p = 0.009), and total number of steps (p = 0.002), while in the females a significant difference was found in peak head yaw velocity between fast and slow turn speeds, and moderate and slow turn speeds. Finally, there was no significant difference in TUG between groups. Therefore, these findings show differences between biological sexes in the response to whole-body coordination and step characteristics, indicating that females tend to have more changes in stepping characteristics compared to males due to differences in turning speed. This can affect their balance and stability. However, the differences in biological sex did not impact the dynamic balance and fall risk due to the lack of a significant difference shown by TUG between males and females.

People with multiple sclerosis and unilateral peripheral vestibular loss demonstrate similar alterations in head and trunk turning kinematics compared to healthy controls

BackgroundIndividuals with peripheral vestibulopathy are known to have difficulty with volitional head turns. This leads to differences in head and body turning kinematics, compared to those without vestibular dysfunction. Multiple sclerosis (MS), a neuro-inflammatory disease affecting the central nervous system, can cause vestibular dysfunction (dizziness, unsteadiness, gaze instability). However, head and trunk turning kinematics in people with MS (PwMS) have not been assessed. Research questionWill PwMS, demonstrate head and body kinematics alterations similar to individuals with a peripheral dysfunction compared to vestibular healthy individuals? MethodsEleven individuals with a recent vestibular schwannoma resection (VSR), fourteen PwMS, and 10 healthy control (HC) participants were fitted with head and trunk worn inertial measurement units (IMUs) and performed walking and turning tasks. Head and trunk peak turning speed and amplitude were extracted. Regression models controlling for gait speed were fit per outcome with post hoc corrections applied to significant models. ResultsYaw plane head turn speed and amplitude were significantly less in the VSR group compared to HC. Pitch plane head turn amplitude was significantly smaller in PwMS compared to HC (p = 0.04), however pitch plane speed did not differ between the groups. There was no difference between PwMS and the VSR group in yaw or pitch plane speed and amplitude. Both PwMS and the VSR group turned significantly slower than HC during the 180d body turn as measured at the head and trunk (head speed model p = 0.009 and <0.001; trunk speed model p < 0.001 for both groups) however the MS and VSR groups did not differ from each other. SignificanceTurning kinematics while walking in PwMS are altered compared to HC and are similar to individuals with unilateral vestibular hypofunction. Centrally mediated vestibular dysfunction in PwMS may alter movement kinematics and should be considered during examination and treatment.

Stable Bilateral Teleoperation Control Method for Biped Robots with Time-Varying Delays

This document proposes a control scheme applied to delayed bilateral teleoperation of the forward and turn speed of a biped robot against asymmetric and time-varying delays. This biped robot is modeled as a hybrid dynamic system because it behaves as a continuous system when the leg moves forward and discrete when the foot touches the ground generating an impulsive response. It is proposed to vary online the damping according to the time delay present in the communication channel, and the walking cycle time using an optimization criterion, to decrease the teleoperation system errors. To accomplish this, a three-phase cascade calibration process is used, and their benefits are evidenced in a comparative simulation study. The first phase is an offline calibration of the inverse dynamic compensation and also the parameters of the bilateral controller. The second phase guarantees the bilateral coordination of the delayed teleoperation system, using the Lyapunov–Krasovskii stability theory, by changing the leader damping and the equivalent follower damping together. The third phase assures a stable walk of the hybrid dynamics by controlling the walking cycle time and the real damping to move the eigenvalues of the Poincaré map, numerically computed, to stable limit cycles and link this result with an equivalent continuous system to join both phases. Additionally, a fictitious force was implemented to detect and avoid possible collisions with obstacles. Finally, an intercontinental teleoperation experiment of an NAO robot via the Internet including force and visual feedback is shown.

High-Performance Oxygen Evolution Reaction Electrocatalysts Discovered via High-Throughput Aerogel Synthesis

A combinatorial high-throughput aerogel synthesis method is developed to systematically study the synergistic catalytic effects of multiple non-noble metal elements. A large number of aerogels with different compositions were synthesized and the corresponding ternary phase diagrams of the composition–electrocatalytic performance were constructed. A batch of aerogel catalysts with outstanding catalytic performance and stability for the electrochemical oxygen evolution reaction (OER) were discovered. Amorphous Fe3Co3Ni2-(oxy)hydroxide with excellent electrocatalytic performance (Tafel slope of 49 mV dec–1 and η100 of 421.48 ± 6.41 mV) was found to achieve a mass activity of 611.23 A/gmetal at 1.63 V (vs RHE). X-ray photoemission spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) studies reveal that the incorporation of a third atom (Ni and Ce) into the binary aerogels enlarges the Co–O atomic distance and reduces the average valence state of Co, which in turn speed up the oxygen evolution reaction kinetics. This work puts forward a strategy for high-throughput synthesis and screening of electrocatalysts and provides valuable data sets for future machine learning and prediction of high-performance electrocatalysts.

A Comparison of Turning Kinematics at Different Amplitudes during Standing Turns between Older and Younger Adults

It is well-established that processes involving changing direction or turning in which either or both standing and walking turns are utilized involve coordination of the whole-body and stepping characteristics. However, the turn context and whole-body coordination have not been fully explored during different turning amplitudes. For these reasons, this present study aimed to determine the effects of turning amplitude on whole-body coordination. The findings from this study can be utilized to inform the rationale behind fall prevention factors and to help design an exercise strategy to address issues related to amplitude of turning in older adults. Twenty healthy older and twenty healthy younger adults were asked to complete standing turns on level ground using three randomly selected amplitudes, 90°, 135° and 180°, at their self-selected turn speed. Turning kinematics and stepping variables were recorded using Inertial Measurement Units. Analysis of the data was carried out using Mixed Model Analysis of Variance with two factors (2 groups × 3 turning amplitudes) and further post hoc pairwise analysis to examine differences between factors. There were significant interaction effects (p &lt; 0.05) between the groups and turning amplitudes for step duration and turn speed. Further analysis using Repeated Measure Analysis of Variance tests determined a main effect of amplitude on step duration and turn speed within each group. Furthermore, post hoc pairwise comparisons revealed that the step duration and turn speed increased significantly (p &lt; 0.001) with all increases in turning amplitude in both groups. In addition, significant main effects for group and amplitudes were seen for onset latency of movement for the head, thorax, pelvis, and feet, and for peak head–thorax and peak head–pelvis angular separations and stepping characteristics, which all increased with turn amplitude and showed differences between groups. These results suggest that large amplitude turns result in a change in turning and stepping kinematics. Therefore, when assessing the turning characteristics of older adults or those in frail populations, the turning amplitude should be taken into account during turning, and could be gradually increased to challenge motor control as part of exercise falls prevention strategies.

Strength Training in Swimming

This narrative review deals with the topic of strength training in swimming, which has been a controversial issue for decades. It is not only about the importance for the performance at start, turn and swim speed, but also about the question of how to design a strength training program. Different approaches are discussed in the literature, with two aspects in the foreground. On the one hand is the discussion about the optimal intensity in strength training and, on the other hand, is the question of how specific strength training should be designed. In addition to a summary of the current state of research regarding the importance of strength training for swimming, the article shows which physiological adaptations should be achieved in order to be able to increase performance in the long term. Furthermore, an attempt is made to explain why some training contents seem to be rather unsuitable when it comes to increasing strength as a basis for higher performance in the start, turn and clean swimming. Practical training consequences are then derived from this. Regardless of the athlete’s performance development, preventive aspects should also be considered in the discussion. The article provides a critical overview of the abovementioned key issues. The most important points when designing a strength training program for swimming are a sufficiently high-load intensity to increase maximum strength, which in turn is the basis for power, year-round strength training, parallel to swim training and working on the transfer of acquired strength skills in swim training, and not through supposedly specific strength training exercises on land or in the water.

Anemia and associated factors among patients admitted with metabolic syndromes at Worabe Comprehensive Specialized Hospital, Southern Ethiopia: A cross-sectional study.

BackgroundAnemia is a condition in which the number of red blood cells is inadequate to meet the physiologic needs of the human body oxygen and it is highly prevalent among individuals with metabolic syndromes as a complication in turn speed up the progression and the number of adverse outcomes unless the proper measure is undertaken. Determination of anemia may play a major role in the management and early aversion of complications in an admitted patient with metabolic syndromes. Therefore, this study aimed to determine anemia and its associated factors among patients with admitted metabolic syndromes at Worabe Comprehensive Specialized hospital, Southern Ethiopia from March 1 to May 30, 2021.Methods and materialsAn institutional-based cross-sectional study design was conducted on 324 adult patients admitted with metabolic syndromes. Structured questionnaires through face-to-face interviews and participants’ medical records were used to collect information on determinants related to anemia. A blood sample was collected to determine hematological parameters, biochemical profile, and blood film preparation. Data were analyzed by SPSS version 22. Binary logistic regression analyses were done to identify factors associated with anemia. The p-value was set at <0.05 with a 95% confidence interval of the adjusted odds ratio.ResultsA total of 324 admitted adult patients with metabolic syndromes were involved. The overall prevalence of anemia among study participants was 25.3% (95%CI: 20.7, 30.2), of which 52.4% had moderate anemia and 56% had microcytic types of anemia. Being alcoholic (AOR = 6.25, 95% CI: (3.05, 12.82)), obese (AOR = 3.34, 95% CI: (1.02, 11.21)), dyslipidemic (AOR = 2.06, 95% CI: (1.02, 4.17)), and diabetic (AOR = 2.61, 95%CI: (1.31, 5.21)) were significantly associated with anemia.ConclusionThe prevalence of anemia among patients admitted with metabolic syndrome observed in this study was a moderate public health problem. Taking alcohol, being dyslipidemic, obese and diabetic was significantly associated with anemia. The finding of this study should be taken into consideration to implement preventive interventions on identified factors in study percipients. Taking fruit and vegetable, and promoting physical exercise, routine determination of fasting blood glucose and hemoglobin level in adult admitted metabolic syndromes patients were recommended to minimize the emergence of anemia.

Rubik’s cube: What separates the fastest solvers from the rest?

The Rubik’s Cube is a 3D combination puzzle. Speedcubing is the activity of solving Rubik’s Cubes as fast as possible. In this paper, we identified and quantified key factors that enable some speedcubers to be faster than others. Knowledge of these factors could allow speedcubers to focus their practice deliberately into specific areas, accelerating their improvement. We hypothesized that a low fraction of pause times, low regrip frequency, and low move counts would show the strongest correlations with faster solves. To test this, we analyzed 69 solve videos frame by frame across a wide variety of ability levels, as well as survey data collected from 1,385 speedcubers. To our knowledge this study represents the most comprehensive factor study of speedcubing to date. We discovered that the following factors correlate most strongly with solve times: frequency of regrips and rotations, fraction of time spent pausing, cross move count, number of algorithms known, turn speed, duration of pause in transition between cross and first two layers (F2L) steps, and orientation of the last layer (OLL) and permutation of the last layer (PLL) recognition time. Based on our findings, we generated specific recommendations for how speedcubers of different ability levels might most efficiently improve their solve times.

CFD Analysis of S-Duct with Varying Area Distributions

The ideal design of an intake S-duct (serpentine duct) of the jet engine should be able to supply adequate air regardless of the operating conditions of the aircraft, efficiently decrease the speed of incoming compressible flow and turn it to the desired location. Total pressure losses should be as low as possible and pressure recovery should be as high as possible. To maximize the efficiency, the vortex generated due to the two curvatures must be suppressed. This can be achieved by varying the area distribution of the duct which helps in isolating the effects of diffusion and curvature as much as possible. In this numerical analysis, six different serpentine intake ducts are designed with varying area distributions, but a constant centerline. The inlet area and the exit area are kept constant along with the centerline. Total pressure contours and transverse velocity contours are observed for flow in each duct to find the duct configuration with least losses. The geometry of a duct with least total pressure loss is considered as the duct with optimum area distribution. The inlet boundary condition is set as the velocity inlet condition with velocity 204.1m/s while, the outlet boundary condition is set as the pressure outlet condition, with outlet pressure of 1 atm. The losses are found to be minimal in the ‘duct 5’ with least transverse flow. This is due to the efficient area distribution which result in initial acceleration and completion of diffusion much before the exit plane causing suppression of vortex at the bend. This in turn helps the ‘duct 5’ to retain its flow energy along the centerline direction resulting in better pressure recovery.

Driving With Distraction: Measuring Brain Activity and Oculomotor Behavior Using fMRI and Eye-Tracking.

IntroductionDriving motor vehicles is a complex task that depends heavily on how visual stimuli are received and subsequently processed by the brain. The potential impact of distraction on driving performance is well known and poses a safety concern – especially for individuals with cognitive impairments who may be clinically unfit to drive. The present study is the first to combine functional magnetic resonance imaging (fMRI) and eye-tracking during simulated driving with distraction, providing oculomotor metrics to enhance scientific understanding of the brain activity that supports driving performance.Materials and MethodsAs initial work, twelve healthy young, right-handed participants performed turns ranging in complexity, including simple right and left turns without oncoming traffic, and left turns with oncoming traffic. Distraction was introduced as an auditory task during straight driving, and during left turns with oncoming traffic. Eye-tracking data were recorded during fMRI to characterize fixations, saccades, pupil diameter and blink rate.ResultsBrain activation maps for right turns, left turns without oncoming traffic, left turns with oncoming traffic, and the distraction conditions were largely consistent with previous literature reporting the neural correlates of simulated driving. When the effects of distraction were evaluated for left turns with oncoming traffic, increased activation was observed in areas involved in executive function (e.g., middle and inferior frontal gyri) as well as decreased activation in the posterior brain (e.g., middle and superior occipital gyri). Whereas driving performance remained mostly unchanged (e.g., turn speed, time to turn, collisions), the oculomotor measures showed that distraction resulted in more consistent gaze at oncoming traffic in a small area of the visual scene; less time spent gazing at off-road targets (e.g., speedometer, rear-view mirror); more time spent performing saccadic eye movements; and decreased blink rate.ConclusionOculomotor behavior modulated with driving task complexity and distraction in a manner consistent with the brain activation features revealed by fMRI. The results suggest that eye-tracking technology should be included in future fMRI studies of simulated driving behavior in targeted populations, such as the elderly and individuals with cognitive complaints – ultimately toward developing better technology to assess and enhance fitness to drive.

Inertial Sensor Reliability and Validity for Static and Dynamic Balance in Healthy Adults: A Systematic Review.

Compared to laboratory equipment inertial sensors are inexpensive and portable, permitting the measurement of postural sway and balance to be conducted in any setting. This systematic review investigated the inter-sensor and test-retest reliability, and concurrent and discriminant validity to measure static and dynamic balance in healthy adults. Medline, PubMed, Embase, Scopus, CINAHL, and Web of Science were searched to January 2021. Nineteen studies met the inclusion criteria. Meta-analysis was possible for reliability studies only and it was found that inertial sensors are reliable to measure static standing eyes open. A synthesis of the included studies shows moderate to good reliability for dynamic balance. Concurrent validity is moderate for both static and dynamic balance. Sensors discriminate old from young adults by amplitude of mediolateral sway, gait velocity, step length, and turn speed. Fallers are discriminated from non-fallers by sensor measures during walking, stepping, and sit to stand. The accuracy of discrimination is unable to be determined conclusively. Using inertial sensors to measure postural sway in healthy adults provides real-time data collected in the natural environment and enables discrimination between fallers and non-fallers. The ability of inertial sensors to identify differences in postural sway components related to altered performance in clinical tests can inform targeted interventions for the prevention of falls and near falls.

The Effect of Different Turn Speeds on Whole-Body Coordination in Younger and Older Healthy Adults.

Difficulty in turning is prevalent in older adults and results in postural instability and risk of falling. Despite this, the mechanisms of turning problems have yet to be fully determined, and it is unclear if different speeds directly result in altered posture and turning characteristics. The aim of this study was to identify the effects of turning speeds on whole-body coordination and to explore if these can be used to help inform fall prevention programs in older adults. Forty-two participants (21 healthy older adults and 21 younger adults) completed standing turns on level ground. Inertial Measurement Units (XSENS) were used to measure turning kinematics and stepping characteristics. Participants were randomly tasked to turn 180° at one of three speeds; fast, moderate, or slow to the left and right. Two factors mixed model analysis of variance (MM ANOVA) with post hoc pairwise comparisons were performed to assess the two groups and three turning speeds. Significant interaction effects (p < 0.05) were seen in; reorientation onset latency of head, pelvis, and feet, peak segmental angular separation, and stepping characteristics (step frequency and step size), which all changed with increasing turn speed. Repeated measures ANOVA revealed the main effects of speeds within the older adults group on those variables as well as the younger adults group. Our results suggest that turning speeds result in altered whole-body coordination and stepping behavior in older adults, which use the same temporospatial sequence as younger adults. However, some characteristics differ significantly, e.g., onset latency of segments, peak head velocity, step frequency, and step size. Therefore, the assessment of turning speeds elucidates the exact temporospatial differences between older and younger healthy adults and may help to determine some of the issues that the older population face during turning, and ultimately the altered whole-body coordination, which lead to falls.

Detection of Wandering Behaviors Using a Body-Worn Inertial Sensor in Patients With Cognitive Impairment: A Feasibility Study.

Patients with Alzheimer's disease (AD) and AD related dementias (ADRD) often experience spatial disorientation that can lead to wandering behavior, characterized by aimless or purposeless movement. Wandering behavior has been associated with falls, caregiver burden, and nursing home placement. Despite the substantial clinical consequences of wandering, there is currently no standardized approach to objectively quantify wandering behavior. In this pilot feasibility study, we used a lightweight inertial sensor to examine mobility characteristics of a small group of 12 older adults with ADRD and mild cognitive impairment in their homes. Specifically, we evaluated their compliance with wearing a sensor for a minimum of 4 days. We also examined the ability of the sensor to measure turning frequency and direction changes, given that frequent turns and direction changes during walking have been observed in patients who wander. We found that all patients were able to wear the sensor yielding quantitative turn data including number of turns over time, mean turn duration, mean peak turn speed, and mean turn angle. We found that wanderers make more frequent, quicker turns compared to non-wanderers, which is consistent with pacing or lapping behavior. This study provides preliminary evidence that continuous monitoring in patients with dementia is feasible using a wearable sensor. More studies are needed to explore if objective measures of turning behaviors collected using inertial sensors can be used to identify wandering behavior.

U-turn speed is a valid and reliable smartphone-based measure of multiple sclerosis-related gait and balance impairment

BackgroundPeople living with multiple sclerosis (MS) experience impairments in gait and mobility, that are not fully captured with manually timed walking tests or rating scales administered during periodic clinical visits. We have developed a smartphone-based assessment of ambulation performance, the 5 U-Turn Test (5UTT), a quantitative self-administered test of U-turn ability while walking, for people with MS (PwMS). Research questionWhat is the test-retest reliability and concurrent validity of U-turn speed, an unsupervised self-assessment of gait and balance impairment, measured using a body-worn smartphone during the 5UTT? Methods76 PwMS and 25 healthy controls (HCs) participated in a cross-sectional non-randomised interventional feasibility study. The 5UTT was self-administered daily and the median U-turn speed, measured during a 14-day session, was compared against existing validated in-clinic measures of MS-related disability. ResultsU-turn speed, measured during a 14-day session from the 5UTT, demonstrated good-to-excellent test-retest reliability in PwMS alone and combined with HCs (intraclass correlation coefficient [ICC] = 0.87 [95 % CI: 0.80–0.92]) and moderate-to-excellent reliability in HCs alone (ICC = 0.88 [95 % CI: 0.69–0.96]). U-turn speed was significantly correlated with in-clinic measures of walking speed, physical fatigue, ambulation impairment, overall MS-related disability and patients’ self-perception of quality of life, at baseline, Week 12 and Week 24. The minimal detectable change of the U-turn speed from the 5UTT was low (19.42 %) in PwMS and indicates a good precision of this measurement tool when compared with conventional in-clinic measures of walking performance. SignificanceThe frequent self-assessment of turn speed, as an outcome measure from a smartphone-based U-turn test, may represent an ecologically valid digital solution to remotely and reliably monitor gait and balance impairment in a home environment during MS clinical trials and practice.

Differences in kinematic parameters between male and female hammer throw finalists of the World Championship in Daegu in 2011

Background and Study Aim. Hammer throwing is the most complex athletic throwing discipline with rotational trajectory and strong effect of several different forces that try to disable the projected throwing trajectory. Kinematic parameters are an important segment in the analysis of athletic disciplines, including hammer throw. They are an indicator of influence and often a difference between competitors of different or the same rank of the competition.&#x0D; The aim of the study was to determine the spatial and temporal differences of kinematic parameters between male and female elite hammers.&#x0D; Material and Methods. The study was conducted on sample of 16 Daegu World Championship finalists in 2011, to analyse differences in kinematic parameters between male and female throwers hammer. To obtain the required results, t-test for small independent samples was applied.&#x0D; Results. The data obtained in the study were given as Mean and Standard deviation. Statistically significant differences between male and female finalists were confirmed in the rate of ejection (t=3.684; p&lt;0.004) and the speed of the fourth turn (t=4.396; p&lt;0.002). The male finalists achieved an average ejection velocity of 27.91m/s and the female finalists 27.17m/s, with an average turn speed of 4.67m/s (male) and 4.03m/s (female).&#x0D; Conclusions. The research has shown that significant differences were made between male and female finalists in Daegu in 2011. The causes of differences can be found in length of training, different training process, technical mastery, competitor experience, morphological profile, motor and anatomical structures, movement technique and biomechanical parameters, which were not taken into the research.

Preventing injuries in alpine skiing giant slalom by shortening the vertical distance between the gates rather than increasing the horizontal gate offset to control speed

Background/AimTo set a safe giant slalom course, speed needs to be controlled in certain sections. Speed may be reduced by adjusting how the gates are set on a course. We...

Biomechanical Analysis Hammer Throw: The Influence of Kinematic Parameters on the Results of Finalists World Championships

Background: Hammer throw is the most complex athletic throwing discipline with a rotational trajectory and the strong action of several different forces that try to disable the projected throwing trajectory. Kinematic parameters are an important segment in the analysis of athletic disciplines, including hammer throw. Aim study: The aim of the study was to determine the influence of spatial and temporal biomechanical parameters on hammer throw results. Methods: The study was conducted on a sample of 56 male and female World Championship finalists (Berlin, 2009, Daegu, 2011, London, 2017). Multiple regression analysis was applied to determine the influence of defined kinematic parameters on the result performance of the throw. Result: The results of the male finalists confirmed the direct correlation between the starting speed (r=0.64 p=0.001), the first turn speed (r=0.47 p=0.017), the release velocity (r=0.86 p=0.000), the release of angle (r=0.37 p=0.049), and the inverse effect of the duration of the first (r=-0.40 p=0.046) and third turn (-0.46 p=0.020). The regression function of the male sample also confirmed the influence of starting speed, release of velocity (p=0.01 p) and angle of release (p=0.04 p). In the female finalists, the direct correlation is between the release of velocity (r=0.90 p=0.000), the angle of release (r=-0.62 p=0.000) and the fourth turn speed (r=0.50 p=0.002). The regression function for the female sample confirmed a high negative influence of the starting speed, while the direct influence was recorded at the release of velocity (p=0.02 p) at the given level of statistical significance of the regression function. Conclusion: The defined set of kinematic parameters had a significant impact on the result performance of male and female hammer throw finalists.