Sudden Changes In Direction Research Articles

Clinical and epidemiological profile of the patients with anterior cruciate ligament tear attending a tertiary care hospital at Srinagar

Background: Anterior cruciate ligament (ACL) is the most frequently injured knee ligament especially as regards sports that include movements with sudden direction changes as knee supports body weight during them. The ACL is crucial in stabilizing the knee joint. The objective of the study was to describe the general and clinical profile of the patients having ACL tear. Methods: This was a hospital based cross-sectional observational study. It was conducted on patients with ACL tear presenting to the department of orthopaedics SKIMS medical college and hospital Bemina from-December 2019 to June 2021. Information was obtained about the general characteristics and clinical profile of the patients. Knee stability was assessed by stability tests, Lysholm knee scoring and international knee documentation committee (IKDC) scale. Results: Of the 40 patients, 50% belonged to the age-group of 31-50 years, 90% were males and 57.5% (n=23) were from rural areas. Sports injury was most common 35%. Giving way was the most common presenting symptom (100%) followed by locking (57.5%). Maximum patients 25(62.5%) had a score of 2 for manual Lachman grading, anterior drawer test 28 (70%) and Pivot shift grading 21(52.5%) whereas for Tegner activity level 23 (57.5%) had a score of 3. The mean Lysholm knee scoring was 64.65±6.82 and the mean IKDC scoring was 51.88±6.70. Conclusions: ACL injury is mostly found in young people with active lifestyle. Sports related activities and road traffic accidents are the most common cause of ACL injury. Giving way and locking of the knee are the most common symptoms.

Mother and calf humpback whale responses to vessels around the Abrolhos Archipelago, Bahia, Brazil

As the humpback whale population spreads along the Brazilian coast, whalewatching activities are becoming more frequent especially along the coast of the state of Bahia. In order to evaluate the appropriateness of the Brazilian legislation that regulates vessel approaches to cetaceans, the behaviour of humpback whale mothers and calves was studied around the Abrolhos Archipelago, an area with a high concentration of tourism vessels. Mother and calf groups were observed by means of continuous sampling and tracked along with vessels using a theodolite. Three whale-vessel categories of distances were analysed: closer than 100m (category 1); between 100-300m (category 2); and further than 300m (category 3). Rates of behavioural events and time spent in particular behavioural states of mothers and calves were compared separately in the three categories to observations of randomly selected mother and calf groups not involved in an interaction with a vessel (category 0). A total effort of 39hr was analysed including observations in each of the four categories. The results showed that differences in humpback whale mother and calf behaviour occurred mostly in the presence of vessels within distances of 100-300m. Mothers increased linearity and mean speed of movement, decreased blow intervals and time spent resting. Calves exhibited less rolling, fluke-ups and others active behavioural events, as well as diminished resting time. During interaction with vessels, the frequency of potentially important behaviours, both for mothers and calves, reduced, probably as a response to the approaching whalewatching vessels. Repeated short-term behavioural disturbances might lead to cumulative effects that may result in risks for species conservation. It is recommended that the Brazilian legislation should include a 300m-radius restrictive zone around mother and calf groups or include a 300m caution zone, where boats should reduce speed and avoid sudden changes in engine status and direction. The environmental education work with local communities along the coast must be continued and constant.

Predator escape behaviour in threatened marsupials

AbstractEscaping from predators is fundamental for the survival of any prey species. Australian fauna within the ‘critical weight range’ (CWR; 35 g–5.5 kg) are vulnerable to introduced eutherian predators. The absence of co‐evolution between native marsupials and these novel predators may suggest that their antipredator behaviour towards the hunting strategies of these predators is inappropriate or ineffective. We quantified the escape behaviour of eight CWR marsupial taxa (three quadrupedal bandicoots and five bipedal macropods) to determine if differences in how they escape from predators indicate their ability to respond appropriately and effectively to introduced predators. Animals were filmed escaping through a runway and 20 measures relating to their gait, speed and path characteristics were recorded. These were reduced to four dimensions using multidimensional scaling (MDS): MDS1 linear speed versus agility, MDS2 acceleration style, MDS3 reactivity and MDS4 gait characteristics. We found a strong link between the phylogenetic relatedness of species and their use of linear speed or agility when fleeing (phylogenetic heritability, h2 = 0.96). Bipedal macropod species used straight‐line, fast escapes, which may be suited to escape pursuit predators. The quadrupedal bandicoots had an overall slower escape but were more likely to use sudden changes of direction, which can be successful if pursued by a larger, less mobile predator or where there is sufficient vegetation cover to obstruct pursuit. Repeated exposure increased linear speed (MDS1) and hastened the timing of acceleration (MDS2). The phylogenetic signal for escape speed/straightness suggests specific escape tactics may be constrained by morphology, although animals increased the intensity of their response after repeated exposure, suggesting training could enhance effective antipredator responses.

The Practicality and Effectiveness of Soccer Scoring Techniques Revealed by Top Elite Soccer Scorers

Background: Although there are 43 soccer scoring techniques (SSTs) identified in the elite soccer games, most of them are overlooked by the current coaching practice. Obviously, the lack of scientific quantification on the fundamental issues related to SSTs could be one of the reasons for the crisis. Therefore, improving coaching practice requires efforts on fundamental researches to supply evidences that can be used to better guide the SST research and the development of SST training systems. Two of the fundamental aspects are the practicality and effectiveness of SSTs. The current study aims to uncover these two aspects. Method: All repeated nominees of the FIFA Puskás Award were selected as study subjects. The terminology system and the identification method developed by Zhang in 2021 were applied in scoring video analysis of the subjects’ career goals. The percentage of goal obtained by each SST (practicality) and ball possessions before shooting for each goal (effectiveness) were determined to reveal the SSTs’ practicality and shooting effectiveness of the top elite scorers. In total, 2315 goals were quantified. Results and Conclusion: The study has unveiled: 1) the practicality is increased if a SST can be applied in shots under all-body-orientation regardless of the ball spatial position at the instant of shooting, 2) the practicality is also associated with the SSTs that can provide either sudden change of ball motion direction at the instant of shooting or unpredictable ball flight, 3) the effectiveness is linked to shots taken with no or one setting of the ball, and 4) the practicality and effectiveness do not always go along with each other and anthropometrically-dependent characteristics should be considered in SST development. As the 1st pilot investigation on the topic, this study would supply a foundation and rich food for speculative thoughts in further explorations that aim to innovatively develop SSTs’ training systems in the future.

Analysis of the spinal 3D motion of postmortem human surrogates in nearside oblique impacts

Objective: The objective of this study is to analyze the 6 degrees of freedom (DOF) motion of the spine using the finite helical axis (FHA) in three postmortem human surrogates (PMHS) sled tests. Methods: The sled test configurations corresponded to a 30° nearside oblique impact at 35 km/h. Two different restraint system versions (RSv) were used. RSv1 was used for PMHS A and B while RSv2 was used for PMHS C. The 6 DOF motion of the head and three selected vertebrae have been analyzed using the FHA which describes the 3 D motion of a rigid body between two instants of time as a rotation about and a translation along a unit vector. A minimal amount of rotation is necessary to the FHA calculation, thus the FHA components have been calculated based on a pre-defined interval of 8° of rotation. Results: The analysis of the FHA components demonstrated right lateral bending until around 100 ms, when the rebound phase was reached and the head and the lower spine undergoes left lateral bending. The three PMHS exhibited, in general, flexion movement of the whole body and torsion to the right side of the occupant. This general motion can be associated to the effect of the seatbelt acting as a fulcrum of the rotational movement of the bony landmarks. The interaction of the PMHS with the retention system can be noted by analyzing the time in which the head and the upper spine initiated the rotation and the sudden changes of rotational direction of the three PMHS’s head. Conclusions: The rotational analyses have shown to be more sensitive to experimental events than the trajectory analyses for the studied physical tests. Additionally, the results presented in the present study contributes to the analysis of the body kinematics during an oblique impact and adds new experimental data for Human Body Models (HBM) and Anthropometric Test Devices (ATD) benchmarking.

Accessory Lateral Head of the Right Gastrocnemius Muscle in a 65 year-old White Male Donor

The three muscles that form the calf muscle or triceps surae include the soleus muscle, the gastrocnemius muscle, and the plantaris muscle. Generally, the gastrocnemius muscle consists of a larger medial head and relatively smaller lateral head. It is responsible for plantar flexion of the foot. The lateral head arises from the posterior lateral femoral condyle and the larger medial head originates from the posterior medial femoral condyle. The medial and lateral heads of the gastrocnemius muscle along with the soleus muscle combine to form the Achilles tendon, which inserts onto the posterior surface of the calcaneus. Since the gastrocnemius muscle crosses three joints including the knee and subtalar joints, it can be vulnerable to injury, especially in mature athletes who experience sudden and swift changes in direction associated with muscular overstretching. Other causes of gastrocnemius muscle injury include maximal knee extension and full ankle dorsiflexion. Since the muscle is already prone to injury, anatomical variations of the gastrocnemius muscles may be symptomatic. With muscle variations, there are potential implications and effects on the other structures within the popliteal fossa. Many different anatomical variations have been identified during routine dissections and reported in the literature. Understanding details of these variations is important for diagnostic, surgical and clinical practice and patient management. Here we report on a 65-year-old White Male cadaveric donor with an accessory lateral head of the gastrocnemius muscle found incidentally during a routine dissection.

Entry angle during jump landing changes biomechanical risk factors for ACL injury

ABSTRACT ACL injuries are common among athletes. The injury usually occurs during sport movements involving sudden direction changes when landing and cutting. Twenty-one healthy females performed a series of jump-land-jump movements. They jumped from a 28 cm box onto two in-ground force platforms, followed by a maximal vertical jump. The direction of the first jump was tested with seven entry angles, jumping to the right (90 R, 60 R and 30 R), straight forward (0), and jumping to the left (90 L, 60 L and 30 L). Kinematic and kinetic data were recorded for data analysis. During the first 100 ms of landing, participants had significantly smaller peak knee flexion angles, larger initial knee valgus angles and larger peak knee joint external valgus moments when jumping to the right (90 R, 60 R and 30 R) compared to straight forward (0), and jumping to the left (90 L, 60 L and 30 L). Thus, entry angles to the right may increase the risk of ACL injury in the right knee. We suggest that these types of jumps should be used with caution during ACL rehabilitation, but may be useful for testing ACL risk factors in healthy individuals.

Flow of Ethanol into a Medium with Varying Degrees of Rarefaction

Experimental results of observation of ethanol microjets flowing into a highly rarefied medium (vacuum) through a nozzle are presented. The investigation of the outflow process was carried out both horizontally and vertically in the direction of gravity, when the liquid was expelled from the source. The condition of keeping constant the residual background pressure in the vacuum chamber is much lower than the saturated vapour pressure of the working liquid at a given temperature of the blast. The possibility of simulation of complex processes of the flow of micro-liquids in a space with a given rarefied atmosphere on a compact vacuum gas-dynamic test bench is shown. It is found that the continuous efflux from a thin capillary or a hole of small diameter into a vacuum or a strongly rarefied gaseous medium differs significantly from the well-studied modes of efflux into a dense gaseous medium, as well as from the pulse modes of efflux into a vacuum. The paper describes the main features of the flow and the conditions of the instability emergence. It is shown that the long-term flow of a liquid microjet in a vacuum has a high degree of surface instability, with a large number of sudden changes in direction, structure and observed density. An explanation for the causes of microjet failure, caused mainly by a combination of capillary instability and intense evaporation of superheated liquid from the surface of the jet, is proposed. The formation of surface gas caverns causing explosive collapse of the microjet with ejection of vapor-liquid droplets is established.

Match Analysis, Physical Training, Risk of Injury and Rehabilitation in Padel: Overview of the Literature.

Padel is a racket sport that has been gaining great popularity and scientific interest in recent years. It could be considered to be a high-intensity intermittent sport with valuable cardiovascular and neuromuscular benefits; however, the risk of injury cannot be neglected. To date, there is still a gap of knowledge in the scientific literature on this emergent sport. Therefore, the present review aims to synthetize the current knowledge on padel game dynamics to better characterize the main risk factors, the injury rate and characteristics, and the most effective rehabilitative treatment strategies. PubMed, Scopus, Cochrane, and PEDro were screened up to January 2022 to identify eligible studies focusing on padel players as participants. Out of 160 records, we included 19 studies, which were focused on match analysis, anthropometric and physical training, the risk of injury, and rehabilitative interventions. The results showed that the high action velocity and the sudden changes in direction during a padel match could represent a risk factor for injuries, especially in untrained players. However, the high heterogeneity of the studies in the literature hinders our ability to draw any strong conclusions, and the results should be carefully considered. Future research should address the lack of knowledge on injury mechanisms and type to implement a tailored rehabilitation program.

A osteíte púbica, clínica e tratamento: o que importa saber

Pubic osteitis is an infrequent inflammatory, overuse stress injury of the pubic symphysis (PS) and periarticular soft tissues. This injury can be seen particularly in athletes, especially in those who participate in sports involving running and kicking with sudden changes in speed and direction. Its etiology and clinical presentation are highly variable, which sometimes makes diagnosis difficult. Sports restriction and performance deterioration are frequent in PO and therefore an early diagnosed must be done to avoid chronic progression. Treatment remains controversial due to little scientific evidence.

Interseismic Fault Coupling and Slip Rate Deficit on the Central and Southern Segments of the Tanlu Fault Zone Based on Anhui CORS Measurements

The Tanlu fault zone, extending over 2400 km from South China to Russia, is one of the most conspicuous tectonic elements in eastern Asia. In this study, we processed the Global Positioning System (GPS) measurements of Anhui Continuously Operating Reference System (AHCORS) between January 2013 and June 2018 to derive a high-precision velocity field in the central and southern segments of the Tanlu fault zone. We integrated the AHCORS data with those publicly available for geodetic imaging of the interseismic coupling and slip rate deficit distribution in the central and southern segments of the Tanlu fault zone. This work aims at a better understanding of strain accumulation and future seismic hazard in the Tanlu fault zone. The result indicates lateral variation of coupling distribution along the strike of the Tanlu fault zone. The northern segment of the Tanlu fault zone has a larger slip rate deficit and a deeper locking depth than the southern segment. Then, we analyzed three velocity profiles across the fault. The result suggests that the central and southern segments of the Tanlu fault zone are characterized by right-lateral strike-slip (0.29–0.44 mm/y) with compression components (0.35–0.76 mm/y). Finally, we estimated strain rates using the least-squares collocation method. The result shows that the dilatation rates concentrate in the region where the principal strain rates are very large. The interface of extension and compression is always accompanied by sudden change of direction of principal strain rates. Especially, in the north of Anhui, the dilatation rate is largest, reaching 3.780×10−8/a. Our study suggests that the seismic risk in the northern segment of the Tanlu fault zone remains very high for its strong strain accumulation and the lack of historical large earthquakes.

Knee Trauma.

Knee Trauma.

Features of inviscid fluid microjets outflow into vacuum

The paper presents experimental results on ethanol microjets outflow from a capillary (vertical flow by gravity) and from a hole in the wall (horizontal flow). The long-term liquid microjet flowing into vacuum has been shown to be highly unstable with sudden changes in direction, structure and observable density and essentially differing from well-studied modes of outflow into the atmosphere as well as from the modes of short-term outflow into vacuum. The main specific features of the flows and conditions giving rise to instabilities are described. Possible explanation of the reasons for microjet destruction is given. Keywords: liquid microjet, barocapillary instability of flows, modeling of vacuum conditions, ethanol.

Local Impacts and Surface Characteristics of Cold Pools Wind Gust Observed from Thunderstorm

Cold pools and associated wind storms are frequent occurrences in Southwestern Nigeria, especially during the early monsoon phase. The associated surface wind gust frequently destroys properties resulting in economic losses. Two case events were investigated in this study; one event occurred in May 2019 and the other occurred in March 2020, both in southwestern Nigeria. The National Oceanic and Atmospheric Administration (NOAA) National Center for Environmental Prediction (NCEP)/Climate Prediction Center (CPC) Infrared brightness temperatures and CPC Morphing technique (CMORPH) rainfall products were analysed alongside in-situ observations from the Nigerian Meteorological Agency (NiMET). Other data sources analysed are the National Aeronautics and Space Administration (NASA) Prediction Of Worldwide Energy Resources (POWER) and the World Wide Lightning Location Network (WWLLN). Cold pools were identified in the impacted communities as indicated by surface characteristics investigated from the in-situ observations. There was a sudden change in wind direction, with a simultaneous drop in temperature accompanied by increasing wind speed. Pressure and humidity were observed to change in the same period. Thunderstorms were also present in the impacted communities, as observed by the in-situ observations, in both case events. The presence of lightning as observed by WWLLN agrees with the in-situ thunderstorms. The cloud characteristics showed the presence of cloud shields, by their brightness temperature, over the impacted communities during the period of the cold pools in both case events. The systems were raining at the time of the observations in both cases, consistent with the in-situ thunderstorm observations. The communities were heavily impacted with several properties destroyed in the events. These early monsoon seasonal windstorms require a forecasting tool for their prediction and this study presents an eye-opener for further investigation and innovative research to address the menace.

Towards understanding and controlling of the surface texture pattern in 5-axis ball-end milling using fast texture simulation

Surface texture is critical for the functionality of industrial parts. This work aims to effectively control the surface texture by applying the phase difference angle between adjacent cutting passes using 5-axis ball-end milling. Because the texture pattern is complicated and is formed by combining feed-interval and step-interval scallops, we propose a level-contour-based fast simulation method to effectively generate the surface texture by inputting the phase difference angle with tilt and lead angles of the cutter. After clarifying the influence of these three parameters on the texture pattern, the desired texture was controlled by modifying the tool path according to the simulated phase difference angle. As a result, the milled surface texture corresponded well with the simulation. The details of the cutting features were efficiently and comprehensively simulated. The mechanism underlying the sudden change in the texture ridge direction was clarified as the major-minor ridge transition when the phase difference angle increased to a certain level, wherein the surface roughness could be decreased because the rearrangement of the cutting region reduced the scallop height. The proposed fast simulation method was also applied to the optimization process with a case study to demonstrate the benefits it can bring to the surface texture design and control.

An all-leader agent-based model for turning and flocking birds.

Starting from recent experimental observations of starlings and jackdaws, we propose a minimal agent-based mathematical model for bird flocks based on a system of second-order delayed stochastic differential equations with discontinuous (both in space and time) right-hand side. The model is specifically designed to reproduce self-organized spontaneous sudden changes of direction, not caused by external stimuli like predator's attacks. The main novelty of the model is that every bird is a potential turn initiator, thus leadership is formed in a group of indistinguishable agents. We investigate some theoretical properties of the model and we show the numerical results. Biological insights are also discussed.

ROLE OF MRI IN EVALUATION OF ANTERIOR CRUCIATE LIGAMENT TEAR

Magnetic resonance imaging being a most advanced and non-invasive imaging modality is a gold standard imaging modality in the diagnosis of soft tissue injuries including the injuries of ligament and tendons because of its three dimensional approach. Almost there are 360 joints in human body with the help of which we can move from one place to other, among them knee joint is the largest joint. It is a synovial joint of hinge variety which mainly allows flexion and extension. Knee joint is supported by a huge network of ligaments and tendons which provide a great strength and flexibility to the knee joint. Anterior and posterior cruciate ligament are the important stabilizing ligaments of the knee joint these two ligaments connects the tibia with femur. Injury or torn to them can cause a critical clinical conditions to the patients suffering from that injury. Injury to anterior cruciate ligament is more frequent as compare to other ligamentous injuries of the knee. Injury to ACL occurs mostly by sudden change in direction so because of which it affects the people who take part in different types of sports like basketball, soccer, baseball skiing. Female athletes are at higher risk of having ACL tear as compare to males. ACL tear should be treated properly because injury to it can cause a serious clinical conditions like it can cause the immobilization of the subject until it is treated properly. For the accurate treatment there should be most advanced and highly sensitive diagnostic approach which aids in the addition of accurate information regarding the location, grading and the condition of ACL tear either there is complete or partial tear. Magnetic resonance imaging modality can diagnosis ACL tears with a high accuracy with the help of specific protocols which are more sensitive to soft tissue injuries. Keywords : ANTERIOR CRUCIATE, LIGAMENT TEAR DOI: 10.7176/JHMN/93-10 Publication date: September 30 th 2021

Flexible prediction of opponent motion with internal representation in interception behavior

Skilled interception behavior often relies on accurate predictions of external objects because of a large delay in our sensorimotor systems. To deal with the sensorimotor delay, the brain predicts future states of the target based on the current state available, but it is still debated whether internal representations acquired from prior experience are used as well. Here we estimated the predictive manner by analyzing the response behavior of a pursuer to a sudden directional change of the evasive target, providing strong evidence that prediction of target motion by the pursuer was incompatible with a linear extrapolation based solely on the current state of the target. Moreover, using neural network models, we validated that nonlinear extrapolation as estimated was computationally feasible and useful even against unknown opponents. These results support the use of internal representations in predicting target motion, suggesting the usefulness and versatility of predicting external object motion through internal representations.

The epidemiology of injury and illness at the Vitality Netball World Cup 2019: an observational study

ABSTRACT Background Netball is a physical game with sudden direction changes, decelerations, jumping and landing, stop/start maneuvers and restrictive footwork rules exposing players to injury. Close contact play and shared facilities during tournaments, increase illness risk. Objective: To describe incidence, period prevalence, types and severity of injuries and illnesses during the 10-day Vitality Netball World Cup 2019 (NWC). Methods: All players from 16 teams consented (n = 192). Medical staff recorded injuries (840 exposure hours), illnesses (1440 player-days) and time-loss. Main outcome measures included incidence (I) calculated as injury/1000 player-hours and illness/1000 player-days, period prevalence (PP) and severity (time-loss) of all match injuries and illnesses. Results 39 players sustained 46 match injuries (I = 54.76; PP = 20.31%). Lower limb injuries (I = 29.76), specifically the ankle (I = 13.10) were most common with lateral ankle ligament sprains the highest (I = 17.39). Contact injuries (I = 40.48) significantly exceeded non-contact injuries (I = 14.29; p = 0.0124). Center players sustained most injuries (n = 12; 26%; I = 14.29), followed by goalkeepers (n = 10; 22%; I = 11.90) and goal defenders (n = 8; 17%; I = 9.52). Injuries occurred in almost 50% of matches, and 67% did not result in time-loss. Time-loss injuries (n = 14; 33%) were most frequent in the lower limb (n = 10; 71%) specifically involved lateral ankle ligaments (n = 4; 29%), attributable to contact (n = 11; 79%) and mostly implicated center players and goal defenders (n = 4 each; 29% each). 11 players contracted 11 illnesses (I = 7.64; PP = 5.72%) with respiratory tract illness contributing 36%. Most illnesses did not result in time-loss (91%). Conclusion This is the first study reporting injury and illness during an NWC. Contact was the main mechanism of injury, and 2/3 of injuries did not result in time-loss. The ankle is most commonly injured and center players sustain most injuries. Non-respiratory system disease was most frequent, but upper respiratory tract infection remains the most common diagnosis. Targeted surveillance studies using similar methodology are required to develop injury and illness preventative strategies in elite netball.

Effects of Regional Plyometric Trainings on Agility Performance of Male Volleyball Players

The study aims to investigate the regional plyometric trainings’ effects on the agility performance of male volleyball players. Süleyman Demirel University Volleyball Team with 20 players attended to the study voluntarily. Players were randomly divided into volleyball training group (VTG) (n = 10) and plyometric training group (PTG) (n = 10). As the VTG continued with their routine volleyball training; regional plyometric trainings for the lower extremity were performed to the PTG for 6 weeks, 3 days a week, at least 30 minutes a day in addition to volleyball training. T and Pro-Agility Tests were applied to the groups at the beginning and end of the 6-week period. Descriptive Statistics, Paired T-Test, and Independent T-Test were used for comparison. “p < 0.05” significance level was accepted for the results’ evaluation. Results of comparison of the T and Pro-Agility pre and post tests’ values of the groups, differences were statistically significant in PTG’s values p < 0.05), but no differences were found in VTG’ values (p > 0.05). Also, no differences were found as a result of the comparison of the pre and post T and Pro-Agility Test values between the groups (p > 0.05). Considering that plyometric trainings provide maximum contraction in the shortest time possible and its effect on the characteristics like sudden changes of location and direction in the volleyball, applying plyometric trainings may be thought to be effective in volleyball training programs.