Throwing Speed Research Articles

High-strain rate deformation of aluminum during the Taylor test

The aim of the study is to develop a methodology for assessing changes in the microstructure of aluminum under dynamic deformation in a rather wide range of the strain rate and strain degree. The distribution of the microstructure and the strength properties in the cross-section of pure aluminum samples (A99) after dynamic deformation according to the Taylor test were studied. The tests were carried out at room temperature using a PG-20 light-gas cannon, at sample throwing speeds of 127 and 165 m/sec. An interference microscope (Leica IM DRM) and a scanning electron microscope (Jeol JSM-6490) were used to study the aluminum microstructure; the microhardness measurements were carried out on an HVS-1000 device to study the uniformity of the strain distribution in samples. It is shown that three characteristic areas can be distinguished in aluminum samples after Taylor test: the elastic deformation zone, the plastic deformation zone, and the zone of severe plastic deformation, which is located in the area of collision of the sample with a steel barrier. It is shown that dynamic deformation reduced the grain structure from 1 – 1.1 mm to 2.5 – 3 μm at high impact velocities. An elongated grain shape is observed in the collision zone. The proposed method provided determination of the critical strain degree necessary for the onset of grain fragmentation and allowed us to explain the formation of zones of weak and severe plastic deformation. It is shown that the critical strain degree corresponding to the beginning of grain fragmentation increases from 0.18 to 0.21 with an increase in the throwing speed of the sample from 127 to 165 m/sec. In the zone of weak deformation, plastic deformation proceeds by intragrain riveting and the initial stages of grain fragmentation. In the zone of severe plastic deformation, a fine-grained microstructure is formed, which leads to an increase in the microhardness of aluminum in accordance with the Hall – Petch equation.

THE RELATIONSHIP OF BACK FITNESS, MUSCLE STRENGTH ARM AND HAND STRIP ON THE SPEED OF THE O GOSHI TECHNIQUE IN JUDO ATHLETES IN BANDAR LAMPUNG

This study aims to determine how the relationship between back flexibility, arm muscle strength and grip to the speed of o goshi technique strikes on judo athletes in judo bandar lampung. Data retrieval using method descriptive correlational. The sample is 30 people with data collection technique Total Sampling. The data analysis technique uses Normality Test, Homogeneity Test, Linearity Test and Correlation Product Moment. The results showed that (1) the flexibility of the back muscles gave a relationship to the throw speed of the technique O Goshi by 31.3%, (2) the strength of the arm muscles give a relationship to the throw speed of the technique O Goshi by 48.5%, and (3) Grip hand give a relationship to the speed of dings technique O Goshi by 37.0%. While back muscle flexibility, arm muscle strength, and hand grip give a relationship of 64.6% to the slam speed of the technique O Goshi. From the results of this study, it can be concluded that back flexibility, arm muscle strength and hand grip contribute to the kicking speed of the technique O Goshi, and the biggest contribution to the kicking speed of the technique O Goshi is the arm muscle strength of 48.5%. KEYWORDS: Speed, Muscle Strength, Flexibility, Technique O Goshi.

THE MUSCULOSKELETAL PROFILE OF FEMALE ADOLESCENT ELITE WATER POLO PLAYERS AND THE FACTORS AFFECTING THROWING PERFORMANCE

The musculoskeletal (MSK) profiles of water polo players and other overhead athletes has been shown to relate to injury and throwing performance (TP). There have been no robust studies conducted on the MSK profiles and the variables affecting TP amongst female, adolescent, elite water polo players.A prospective quantitative cohort design was conducted amongst eighty-three female adolescent, elite water polo players (range 14–19 years). All participants filled out the Kerlan-Jobe Orthopaedic Clinic questionnaire, followed by a battery of screening tests aimed to identify possible MSK factors affecting TP. Pain provocation tests, range of motion (ROM), upward scapula rotation (USR), strength and pectoralis minor length measurements were all included. Participants also performed throwing speed (TS) and throwing accuracy (TA) tests.All the data collected were grouped together and analysed using SPSS 28.0. The condition for statistical significance was set as p <0.05. Multi-collinearity was tested for among variables to find out inter-variable correlations. Finally, a multiple regression analysis was performed.The mean KJOC score was 82.55 ± 14.96. 26.5% tested positive for at least one of the impingement tests. The MSK profile revealed decreased internal rotation ROM, increased external rotation ROM, a downwardly rotated scapula, weak external rotators, weak serratus anterior strength, strong lower trapezius and gluteus medius strength and a shorter pectoralis minor length all on the dominant side.Age, pectoralis minor length, upper trapezius and serratus anterior strength as well as upward scapula rotation were all positively correlated with TS, while sitting height, upper trapezius and serratus anterior strength and glenohumeral internal rotation ROM were positively correlated with TA.Multiple MSK parameters were found to be related to TS and TA in elite, adolescent water polo players.

Assessing the validity of an instrumented medicine ball for measuring throw speed

Assessing the validity of an instrumented medicine ball for measuring throw speed

Variable Resistance-An Efficient Method to Generate Muscle Potentiation: A Systematic Review and Meta-Analysis.

Variable resistance (VR) is a methodology that has shown good results in developing muscular strength and power. However, no updated information relates to the use of VR as an activation to trigger post-activation performance enhancement (PAPE). The primary objective of this systematic review and meta-analysis was to review and qualitatively describe studies published between 2012 and 2022 that used VR to generate PAPE in muscle power-dominant sports. The secondary objective was to calculate the effect size of the different power outcomes reported in the selected studies. The search was designed following the PRISMA® guidelines for systematic reviews and meta-analyses and performed in the Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2012 and 2022. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the throwing speed, time in sprint tests, and jump height. The analysis was conducted with a pooled standardized mean difference (SMD) through a Hedges' g test (95% CI). Twenty-two studies were included in the systematic review and ten in the meta-analysis, revealing a trivial effect for throwing speed (SMD = 0.06; CI = 95%: -0.23-0.35; p = 0.69), a small effect for the time in sprint tests (SMD = -0.37; CI = 95%: -0.72--0.02; p = 0.04), and a moderate effect for jump height (SMD = 0.55; CI = 95%: 0.29-0.81; p ˂ 0.0001). All forms of VR used for neuromuscular activation effectively triggered PAPE. Specifically, the results showed that activation with VR generates performance increases in time, in sprint tests and jump height, and a trivial effect in throwing tests (speed and distance).

Physical fitness and throwing speed in U13 versus U15 male handball players

BackgroundThe aim of this study was to analyze the shoulder functional profile (rotation range of motion [ROM] and strength), upper and lower body performance, and throwing speed of U13 versus U15 male handball players, and to establish the relationship between these measures of physical fitness and throwing speed.MethodsOne-hundred and nineteen young male handball players (under (U)-13 (U13) [n = 85]) and U15 [n = 34]) volunteered to participate in this study. The participating athletes had a mean background of sytematic handball training of 5.5 ± 2.8 years and they exercised on average 540 ± 10.1 min per week including sport-specific team handball training and strength and conditioning programs. Players were tested for passive shoulder range-of-motion (ROM) for both internal (IR) and external rotation (ER) and isometric strength (i.e., IR and ER) of the dominant/non-dominant shoulders, overhead medicine ball throw (OMB), hip isometric abductor (ABD) and adductor (ADD) strength, hip ROM, jumps (countermovement jump [CMJ] and triple leg-hop [3H] for distance), linear sprint test, modified 505 change-of-direction (COD) test and handball throwing speed (7 m [HT7] and 9 m [HT9]).ResultsU15 players outperformed U13 in upper (i.e., HT7 and HT9 speed, OMB, absolute IR and ER strength of the dominant and non-dominant sides; Cohen’s d: 0.76–2.13) and lower body (i.e., CMJ, 3H, 20-m sprint and COD, hip ABD and ADD; d: 0.70–2.33) performance measures. Regarding shoulder ROM outcomes, a lower IR ROM was found of the dominant side in the U15 group compared to the U13 and a higher ER ROM on both sides in U15 (d: 0.76–1.04). It seems that primarily anthropometric characteristics (i.e., body height, body mass) and upper body strength/power (OMB distance) are the most important factors that explain the throw speed variance in male handball players, particularly in U13.ConclusionsFindings from this study imply that regular performance monitoring is important for performance development and for minimizing injury risk of the shoulder in both age categories of young male handball players. Besides measures of physical fitness, anthropometric data should be recorded because handball throwing performance is related to these measures.

Fluid Movement Law and Influencing Factors of Shredding on Rice Straw Briquetting Machines

The briquetting technology of rice straw could increase the bulk density of the straw, reduce transportation and storage costs, and improve resource utilization. This paper analyzed the working principle of the air-conveying integrated device in briquetting machines. High-speed photography technology was used to track and record the movement process of crushed straw material in the air-conveying cylinder area. It was compared with the simulation results of the average velocity of crushed straw material to verify the reliability of the simulation. The results showed that the flow of straw scraps in the straw-shredding and air-conveying integrated device was relatively stable when the impeller speed was 630 r/min, the number of blades was three, the blades were tilted back 15°, and the radius of curvature of the air-conveying tube elbow was 700 mm. At the same time, the speed distribution was uniform, and the highest throwing speed reached 4.5 m/s to 4.8 m/s. After optimization, the average increase rate of briquette density was 2.61% and the average increase rate of briquette productivity was 2.52%. The fluid movement law of the straw-shredding and air-conveying integrated device studied in this paper could be used to optimize the air-conveying device, improve the efficiency of straw briquetting and the utilization rate of straw resources.

The influence of acrobatic means on the formation of special physical preparedness in Ukrainian belt wrestling at the specially grained stage

The popularity of belt wrestling forces domestic and foreign experts to reconsider the methods of organizing and conducting the training process on the types of belt wrestling, look for new ways to increase the level of special physical fitness of athletes, quality of study and improvement of technical and tactical actions in the training process, level of competitiveness. Therefore, increasing the level of special physical fitness of athletes at different stages of sports training is accompanied by the promotion of belt wrestling. Ukrainian belt wrestling is also gaining considerable popularity, both in Ukraine and in the world. International and European federations of Ukrainian belt wrestling has been established, and world and European championships are being held. The All-Ukrainian Federation of Ukrainian Belt Wrestling has 14 regional centers that develop Ukrainian belt wrestling among all age groups.
 The aim of the study: the formation of special physical fitness of athletes in the Ukrainian belt wrestling at the stage of specialized basic training. Research methods: analysis and generalization of scientific and methodological literature sources, psychophysiological research methods, pedagogical research methods, mathematical methods of scientific research data processing.
 Conclusions. As a result of the study it can be argued that increasing the share of acrobatic exercises and flexibility exercises in the preparatory part of the training session on Ukrainian wrestling on belts helped to improve the performance of special physical fitness of athletes and their functional status. As a result of the study, the special physical fitness of athletes in the experimental group improved by 19.2%, the highest results of special physical training were established by indicators: partner's throwing speed of 16.5%; running speed around the head 19%; flexibility of 25.6%.

ESTABLISHMENT AND CALIBRATION OF DISCRETE ELEMENT MODEL OF KING GRASS STALK BASED ON THROWING TEST

In order to better use the discrete element method (DEM) to study the cutting and throwing process of King Grass (KG) stalk in mechanical harvesting, the DEM model and contact parameters of KG stalk were studied in this paper. By using the Multi-sphere method, the DEM model of KG stalk was established in EDEM software. Through the impact bounce test and slope sliding test, the stalk-steel coefficient of static friction, stalk-steel coefficient of restitution and stalk-stalk coefficient of restitution were calibrated as 0.372, 0.656 and 0.523, respectively. Based on the stacking test, using the response surface methodology, the optimal values of stalk-stalk coefficient of static friction, stalk-stalk coefficient of rolling friction, stalk-steel coefficient of rolling friction were calibrated as 0.393, 0.072 and 0.144, respectively. The throwing test bench of stalk was designed, and the actual and simulation throwing test were carried out. The relative error of throwing distance in bench test and simulation test under four throwing speeds was 1.15%, 7.76%, 8.88% and 10.46%, respectively. The throwing trajectory curve of the simulation test is consistent with that of the actual test, which verifies the accuracy of the DEM model and contact parameters of KG stalk.

Analysis of the Steps Cycle in the Action of Throwing in Competition in Men’s Elite Handball

The aim of this article was to analyze the step cycle that precedes the throwing action in elite men’s handball and its relationship with different factors, such as throwing distance, throwing technics, throw speed, whether it occurs in jump or standing, the last step, and efficiency. Twenty-four complete matches were analyzed, with a total of 1013 throws in three international elite men’s handball championships. The results show that the most used step cycle is the one performed with two steps. There is a significant relationship between the step cycle and the throw distance, with two-step throws being the most used from outside 9 m (29.8%, p < 0.001), three-step throws at a distance between 6 and 9 m (35.9%, p < 0.001), and zero- and one-step throws from 6 m (30.5%, p < 0.001). Likewise, the last step with natural footing is the most used (93.7%, p < 0.001) with a complete cycle of steps, followed by false foot with more than three steps (27.3%, p < 0.001), and two feet with zero steps (12.6%, p < 0.001). In conclusion, the skill to take advantage of the dynamic improvement offered by the mastery of the step cycle, adapting to the different situations of the game, could be an essential characteristic of the player to effectively complete the throwing action.

Modeling Coastal Freak Wave Occurrence

Fishermen frequently suffer accidents and may even drown when they are swept into the sea by coastal freak waves near the shore of northeastern Taiwan. To accurately predict the deformation of free surfaces when waves violently strike coastal structures, the smoothed particle hydrodynamics (SPH) model with a nonlinear and mesh-free numerical approach was adopted in this study. Eight cases based on an actual coastal freak wave accident were simulated. The results show that the maximum splash height of the coastal freak wave in the breakwater was dependent not only on the incident wave but also on the existence of armor blocks. The armor block installation reduces the overflow discharge but enhances the horizontal throw speed of the coastal freak wave by more than five times.

Simulation analysis and experimental validation of conveying device in uniform rrushed straw throwing and seed-sowing Machines using CFD-DEM coupled approach

• No-till farming is being increasingly used worldwide for more efficient crops. • In crop rotation, the straw of a crop can be used for the next cycle. • We developed a planter that performs even crushed straw coverage. • The coverage and planter performance are verified in simulations and implementation. • We provide the optimal parameters for even coverage and meeting operation standards. In agricultural fields with full straw retention, shredded straw tends to be thrown unevenly. To achieve uniform crushed straw throwing in dense fields of rice stubble, and high-quality straw mulching in dense fields, the conveying device of a no-till planter to perform uniform throwing of crushed straw stubble on fields and determine the device operation mechanism was analyzed. Using kinematics and dynamics analyses of particles of crushed rice straw during lifting and dispersion, a flexible-body model of rod-shaped and agglomerate-shaped crushed straw and a coupling model that included the mechanical structure of the device were developed. By integrating computational fluid dynamics and the discrete element method, the gas–solid coupling theory in numerical simulations and motion analysis of crushed straw particles was used to determine the flow field and motion characteristics under different parameters. The simulation focused on the conveying performance of different pipelines under four scenarios with varying throwing blade speed, conveying volume, pipeline diameter, and initial feeding velocity. The influence of these parameters on both the conveying device performance and their own variation was determined. Actual operations that are then compared with test results to achieve optimal operation were demonstrated. By adopting the Box-Behnken design, the throwing speed of crushed straw was set to the evaluation index a response surface test was performed on the throwing blade speed, conveying volume of crushed straw, and pipeline diameter. The optimization results showed that the predicted optimal parameters were 2300 rpm throwing blade speed, 1.4 kg/s conveying volume, and 220 mm pipeline diameter. The simulated planter achieved an optimized throwing speed of 14.6 m/s. Then, a field test verification was conducted, and the results were averaged. The planter achieved a throwing speed of 14.8 m/s with the same optimal parameters. The straw lifting and throwing device provides high conveying performance and satisfies requirements for real-time operation. This study provides a theoretical basis and supporting data for innovating seeding technologies and optimizing equipment to achieve uniform crushed straw-throwing in dense fields of rice stubble.

Goal Shot Analysis in Elite Water Polo—World Cup Final 2018 in Berlin

The subject of this game analysis was the throwing behavior of the world class players under competition match conditions during the final “World Cup Water Polo” tournament 2018 in Berlin. Specifically, we analyzed (a) the situational dependence of concrete environmental conditions (“constraints”) of successful throwing actions as well as (b) the goal throw biomechanics concerning throwing speed. Therefore, player’s and ball positions were recorded by video cameras as well as high-speed cameras. Based on the positions and trajectories parameters such as goal throw speed, Voronoi-cells as well as team centroids were calculated. The area of the Voronoi-cells differs concerning defending and attacking teams as well as between successful and non-successful teams and can be used as an indicator for goal or no goal. Under semi-collective tactical aspects, the comparison of the offensively and defensively controlled field areas (collective space control) between successful and unsuccessful goal throws shows that in the case of successful attacking completions, the attacking team (in the sum of its six players) each controlled significantly more field area in front of the opponent’s goal than the six defensive players together with their goalkeeper. In the case of unsuccessful attacking attempts, this area ratio was exactly reversed, i.e., the defensive team dominated the space.

Mental imagery of object motion in weightlessness

Mental imagery represents a potential countermeasure for sensorimotor and cognitive dysfunctions due to spaceflight. It might help train people to deal with conditions unique to spaceflight. Thus, dynamic interactions with the inertial motion of weightless objects are only experienced in weightlessness but can be simulated on Earth using mental imagery. Such training might overcome the problem of calibrating fine-grained hand forces and estimating the spatiotemporal parameters of the resulting object motion. Here, a group of astronauts grasped an imaginary ball, threw it against the ceiling or the front wall, and caught it after the bounce, during pre-flight, in-flight, and post-flight experiments. They varied the throwing speed across trials and imagined that the ball moved under Earth’s gravity or weightlessness. We found that the astronauts were able to reproduce qualitative differences between inertial and gravitational motion already on ground, and further adapted their behavior during spaceflight. Thus, they adjusted the throwing speed and the catching time, equivalent to the duration of virtual ball motion, as a function of the imaginary 0 g condition versus the imaginary 1 g condition. Arm kinematics of the frontal throws further revealed a differential processing of imagined gravity level in terms of the spatial features of the arm and virtual ball trajectories. We suggest that protocols of this kind may facilitate sensorimotor adaptation and help tuning vestibular plasticity in-flight, since mental imagery of gravitational motion is known to engage the vestibular cortex.

Studi Performansi Mesin Pelontar Pakan Ikan terhadap Gaya Sentrifugal

The fish feed thrower machine can disperse the feed over a wide coverage area in a short time. Throw distance is an important parameter that must be considered in a fish feed thrower machine. Distribution of feed from the fish feed thrower machine is due to the centrifugal force. This study aims to analyze the rotational speed (RPM) of the fish feed thrower machine 360° against throw distance and centrifugal force of the feed grains. Maximum results obtained for throw distance, throw speed and centrifugal force occur at RPM 600. Farthest throw distances from the feed codes 781-1, 781 and 782 are 2.20 m, 1.89 m and 1.66 m. Maximum throw speeds of the feed codes 781-1, 781 and 782 are 14,667 m/s, 12,583 m/s and 11,083 m/s. Maximum centrifugal force of the feed codes 781-1, 781 and 782 are 0.504x10 -3 N, 2.711x10 -3 N and 5.796x10 -3 N . This shows that the centrifugal force on the feed grains causes the rotational speed (RPM) to affect the distance and speed of the feed.

Effects of Different In-Season Strength Training Methods on Strength Gains and Water Polo Performance

This study aimed to compare the effects of 5 different 18-week in-season strength training programs on strength gains and specific water polo performance. A total of 56 young male water polo players were randomly assigned to the following 5 training groups: dry-land strength training, in-water-specific strength training, combined (dry-land and in-water) strength training, ballistic training, and eccentric-overload training. Physical performance was assessed before (Pre) and after (Post) the training period using the following battery of tests: in-water boost and countermovement jump, muscle strength in bench-press and full-squat, throwing speed (ThS), in-water agility, and 20-m maximal sprint swim. Significant group × time interactions were observed for countermovement jump and in-water boost. Eccentric-overload training showed significantly higher gains in ThS and bench-press and full-squat strength than the rest of the training groups. In addition, all training groups (except in-water-specific strength training) induced significant improvements (P ≤ .05) in countermovement jump, in-water boost, and bench-press and full-squat strength. All training groups significantly increased (P ≤ .001) ThS. Moreover, all training groups improved (P ≤ .05) in-water agility (except dry-land strength training) and swimming sprint performance (except in-water-specific strength training and ballistic training). The findings indicate that the 18-week in-season strength training programs induced improvements in strength and specific water polo skills. The eccentric-overload training resulted in greater improvements in muscle strength (in both upper and lower body) and ThS than the other training methods examined in the study.

Predictors of throwing performance in amateur male cricketers: A musculoskeletal approach

Optimal throwing speed and accuracy is built on a complex interaction of multiple variables. Although strength and power has been associated with throwing speed in cricketers, the individual muscles that contribute to optimal function of the shoulder-complex has not been adequately explored in connection with throwing performance. Consequently, this study aimed to investigate the correlation between musculoskeletal variables and overhead throwing performance in cricketers. Thirty-two amateur male cricketers were tested using a battery of 16 tests (strength, flexibility, scapula positioning) as well as a throwing speed (TS) and a novel accuracy test (TA). Only two of the sixteen tests were correlated with throwing performance in the multiple regression analysis. Non-dominant hip abduction strength correlated positively with TS (p < 0.05): on average, a strength increase of 10 newtons (N) was associated with an increase in TS of 0.60 km/h (95% CI: 0.12–1.08). Non-dominant pectoralis minor length correlated positively with TA (p < 0.01): on average, a one-centimetre increase in the length correlated to an increase, of 0.633 points (95% CI: 0.225–1.041). This cross-sectional study demonstrated that from an array of musculoskeletal variables, only non-dominant hip abduction strength correlated with TS, while only non-dominant pectoralis minor length correlated with TA in amateur cricketers.

The Influence of Morphological Characteristics on Throw Speed in Handball

The diagnosis of morphological characteristics is an integral part of the entire training process in sports. This study aimed to determine the influence of morphological characteristics on the ball's speed of movement after the shoot from a spot and movement in handball. The sample included 36 female handball players aged 14.33 years. The predictor set consisted of 10 morphological variables. In comparison, the three variables constituted the criterion variables by which the ball's speed of movement was determined after different ways of shooting. Using regression analysis, it was found that the predictor set of variables explains about 70% of the variance for all three criterion variables. Individually, a statistically significant and positive influence on the speed of movement of the ball after the shot was recorded at the height and weight of the body, while a negative effect was observed for the variables; arm length, leg length and skin fold on the abdomen. Based on the results obtained, it can be concluded that morphological characteristics significantly influence the speed of movement of the ball after a shot in the handball, which can significantly contribute to the selection of handball players, as well as in establishing the tactics of handball, especially in situations where one shot decides the match. Also, the obtained results indicate the necessity of considering the age characteristics of the female respondents, that is, the need to adjust the training process to the period of intensive growth and development.

ПОДОБИЕ ТРАЕКТОРИЙ ДВИЖЕНИЯ ТЕЛА В СРЕДЕ, СОПРОТИВЛЕНИЕ КОТОРОЙ ПРОПОРЦИОНАЛЬНО КВАДРАТУ ОТНОСИТЕЛЬНОЙ СКОРОСТИ

The force of gravity and the force of air resistance affect a particle thrown at an angle to the horizon with an initial velocity. In the calculation of wind protection and distribution devices, it becomes necessary to reduce the differences in trajectories when changing the type of fertilizer. There are two possibilities for simple adjustments. First, you can try to increase the throwing speed of fertilizers with a high windage factor. Secondly, the initial throwing angle can be adjusted. However, it is not possible to achieve alignment of the trajectories by adjusting the throwing angle. The smallest difference in trajectories was obtained by combining the simultaneous change in the initial angle and throwing speed. By simultaneously adjusting the initial angle and initial throwing speed, it is possible to almost match the trajectories of particles with different wind ratios, which is useful when working with a distributor

EFFECT OF OPPOSITION AND EFFECTIVENESS OF THROWING FROM FIRST AND SECOND LINE IN MALE ELITE HANDBALL DURING COMPETITION

The goalkeeper and defensive player’s degree of opposition could influence throwing velocity and thereby success of scoring goals. Therefore, the aim of this study was to investigate the influence of opposition and contact on throwing velocity and effectiveness in elite team handball players from first and second offensive lines. Throwing velocity from 2893 throws carried out in 47 matches during the Men’s World Handball Championship were analysed. A higher throwing velocity was obtained with opposition and no contact situations. In the comparison between the first and second offensive line players, the same results were obtained in relation to the higher throw speed. Significant relationships were found between the attack effectiveness and the type of opposition and contact. Throws carried out with no opposition either with or without contact are those that more likely end in a goal, while opposition without and with contact decreases the effectiveness in scoring goals. Concerning playing positions, both first and second line showed this significant relationship between attack effectiveness and the type of opposition and contact. It was concluded that opposition and defensive contact have a negative and significant effect on the scoring efficacy. Defensive contact is a determining factor causing a significant decrease on throwing velocity.