Throw Distance Research Articles

Design and Development of an Electromagnetic Catapult for Life-Saving Projectile

In this article, a kind of electromagnetic coil catapult for life-saving projectile (LSP) is designed and developed for water rescue. We adopted the single-stage coil launcher scheme to save costs and improve reliability. Two launch modes, armature-load integrated launch (ALIL) and armature-load separated launch (ALSL), are compared by simulation. In the ALIL mode, LSP and armature are integrated together. The LSP will be decelerated due to the armature drag effect after being launched to the maximum speed. In the ALSL mode, the armature will separate from the LSP after reaching the maximum speed due to the electromagnetic drag force. The LSP will fly out of the catapult at peak speed due to inertia, which will improve the muzzle speed of the LSP compared with the ALIL. Further analysis shows that in the ALSL mode, reducing the initial power supply voltage, reducing the armature-load mass ratio, and increasing the number of coil turns are beneficial to the armature recovery. The armature recovery method can make the armature reusable. A set of electromagnetic catapult devices for LSP is developed. Finally, armature launch and LSP launch tests are carried out. It is proven that the simulation and test results are consistent. Under the full voltage state, the catapult can make the LSP obtain a muzzle speed of 52 m/s, and the throw distance exceeds 180 m. The armature can be recovered and reused. Experiments verify the feasibility of the electromagnetic catapult for LSP, which has good application value.

Adopting a holistic focus of attention promotes adherence and improves performance in college track and field athletes

Research on novices suggests that an external focus improves performance over an internal focus. For experienced performers the results on attentional focus have been mixed. Recently Becker, Georges, and Aiken (2019) suggested that a holistic focus may be a useful substitute when an external focus is not appropriate. The purpose of this study was to investigate attentional focus within track and field athletes performing an underhand shot throw. 18 female athletes performed an underhand shot throw (4 kg) under three focus conditions: internal, external, and holistic. Participants also rated their adherence to each attentional focus manipulation. Repeated-measures ANOVAs with Sidak post-hoc were used to analyze both underhand shot throw distance and focus adherence. A significant main effect for condition was observed for distance (F = 6.14, p = .005). A holistic threw farther than an internal focus (p < .001) with no difference between internal and external (p = .380), or holistic and external foci (p = .312). For adherence, a significant main effect for condition was observed (F = 4.56, p = .018) with holistic focus adhering to the cue significantly more than internal focus (p < .019). The results of this study are in line with research that found a benefit for a holistic focus with novice performers (Becker et al., 2019). Mullen and Hardy (2010) also found a benefit for the golf putt, basketball shot, and long jump with skilled performers adopting a focus on the global or holistic aspect of the skill.

IMPACTOS DO TREINAMENTO POR BOLA MEDICINAL SOBRE A FORÇA EXPLOSIVA EM MEMBROS SUPERIORES DE TENISTAS

ABSTRACT Introduction: Medicine Ball training has a long history as a training to strengthen the musculature of athletes, and tennis requires high explosive muscle strength in the upper limbs of its athletes. Objective: Explore whether medicine ball training can significantly improve explosive forearm strength in tennis players. Methods: 100 professional tennis players with a mean age of 21 years were selected and randomly divided between the experimental and control groups. During 12 weeks of conventional tennis training, an extra training protocol, with Medicine Ball, was added to the experimental group. Results: After the experiment, the performance of the experimental group showed expressive signs of evolution: the forward throwing distance increased by 13.23%, the backward throwing distance increased by 11.96%, the solid ball throwing distance increased by 18.93%, and the touch distance with vertical jump increased by 1.98%. An increase in the experimental group’s overall velocity was also observed, by 18.37%. While the control group did not show expressive changes. Conclusion: The explosive strength of the tennis players’ upper limbs can be effectively improved through the Medicine Ball training presented. The tennis players’ overall speed also benefited, reflecting the improvement of the tennis players’ specific performance. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Factors that Increase Elbow Stress in the Throwing Athlete: a Systematic Review of Biomechanical and Motion Analysis Studies of Baseball Pitching and Throwing.

Elbow pain poses a unique challenge in the throwing athlete. Due to the high levels of elbow stress during the throwing motion, elbow injuries are common in throwers of all ages. There are several postulated factors believed to contribute increased stress to the throwing elbow. A detailed review of the published biomechanical studies evaluating the stresses experienced by the throwing elbow is needed. Here, we review these biomechanical studies to extrapolate the contributing factors that increase stress, the modifications that may reduce such stress, and the post-injury rehabilitation that optimizes outcomes and reduces recurrence. The biomechanical forces on the elbow have been further investigated delineated in recent work. Rotational malalignment of the shoulder, including both GIRD and decreased adduction, increases torque experienced by the elbow during pitching motions. Exact interactions between lower extremity, lumbopelvic or trunk rotation, and elbow forces during throwing remain uncertain with mixed results in recent literature. Pitch types may influence elbow stresses although delivery mechanism and distance thrown do not. Several biomechanical factors influence the stresses imparted on the throwing elbow. Throwing volume, proper throwing mechanics, and appropriate rehabilitation are likely to be to be the most influential on mitigating unnecessary stresses imparted to the elbow in the throwing athlete. A proper understanding of these factors may reduce the occurrence of these injuries in this population. Moreover, an understanding of proper rehabilitation following injury may ensure optimized results and reduce recurrence.

Analysis of pointing accuracy on petanque standing position: Performance and accuracy

In developing the game of pétanque, it is necessary to master good basic techniques because this is the initial capital of an athlete to develop his game. Good mastery of basic techniques can also improve performance optimally. The purpose of this study was to analyze the accuracy of petanque pointing in a standing position at Atlas City Petanque Club (ACPC) athletes in Semarang City. The type of this study is descriptive-quantitative. The sample of this study was 8 athletes of ACPC club in Semarang city consisting one female and seven male athletes. Inclusion criteria in this study was having experience at national or international levels competitions and having trained for at least 6 months. All sample also sign the inform consent as a agreement to participate the research until the end. The results of this study indicate that the analysis of the pointing accuracy in standing position by ACPC club athletes in Semarang City is in the Precise Category, with an average distance of the ball to a target was 0.14 meters. Pointing in a standing position is very effective for a distance of 9 meters due to the ideal body position with a long throw distance from the target. The limitation of this study only focuses on the throwing distance produced by each athlete, so it has not been able to analyze every value generated from each athlete’s throws. Further, research can analyze the backspin technique of pointing in a standing position to complement the current research data.

Effects of New Zealand Blackcurrant Extract on Sequential Performance Testing in Male Rugby Union Players.

Previous studies on performance effects by New Zealand blackcurrant (NZBC) extract used mainly a single exercise task. We examined the effects of NZBC extract in a battery of rugby union–specific tests including speed, agility and strength testing. University male rugby union players (n = 13, age: 21 ± 2 years, height: 182 ± 6 cm, body mass: 87 ± 13 kg) completed two full familiarisations and two experimental visits in an indoor facility. The study had a double blind, placebo-controlled, randomised, crossover design. For the experimental visits, participants consumed NZBC extract (210 mg/day of anthocyanins for 7 days) or placebo with a 7-day wash-out. Testing order was the running-based anaerobic sprint test, the Illinois agility test, seated medicine ball (3 kg) throw, and handgrip strength. With NZBC extract, there may have been an effect for average sprint time to be faster by 1.7% (placebo: 5.947 ± 0.538 s, NZBC extract: 5.846 ± 0.571 s, d = −0.18 (trivial), p = 0.06). However, with NZBC extract there may have been reduced slowing of sprint 2 (d = −0.59 (moderate), p = 0.06) and reduced slowing for sprint 6 (d = −0.56 (moderate), p = 0.03). In the Illinois agility test, there may have also been an effect for the mean time to be faster by 1.6% (placebo: 18.46 ± 1.44 s, NZBC extract: 18.15 ± 1.22 s, d = −0.24 (small), p = 0.07). The correlation between the %change in average sprint time and %change in mean agility time was not significant (Pearson R2 = 0.0698, p = 0.383). There were no differences for the seated medicine ball throw distance (p = 0.106) and handgrip strength (p = 0.709). Intake of NZBC extract in rugby union players seems to improve tasks that require maximal speed and agility but not muscle strength. NZBC blackcurrant extract may be able to enhance exercise performance in team sports that require repeated movements with high intensity and horizontal change of body position without affecting muscle strength.

Relationship of Clubhead Speed With Explosive Power and Muscle Strength of the Hip and Trunk Joints of Elite Golfers.

Suhara, H, Nariai, M, Takagi, T, Akiyama, K, Nagashima, J, and Shiraki, H. Relationship of clubhead speed with explosive power and muscle strength of the hip and trunk joints of elite golfers. J Strength Cond Res 37(4): 859-865, 2023-In golf, the driving distance of the ball is affected by the clubhead speed (CHS) on impact. We aimed to clarify the relationship between CHS and explosive power and muscle strength of the hip and trunk muscles in elite golfers (male age: 19.6 ± 1.9 years, male handicap: 4.4 ± 0.9, female age: 17.7 ± 1.4 years, and female handicap: 6.2 ± 0.7). A correlational design was used to assess the relationships between CHS and strength (hip extension-flexion and trunk rotation of peak torque at an isokinetic 60 and 180°·s -1 angular velocity) and CHS and power (countermovement jump [CMJ]; peak power and jump height; backward overhead medicine ball [BOMB] throw). Fourteen each of male and female elite golfers were included. The CHS during the golf swing was measured using a Doppler radar measurement device (Trackman). A correlation analysis between each measurement and CHS ( p ≤ 0.05) was conducted. We found that the peak torque of right hip extension at an angular velocity of 180°/s (male, r = 0.67; female, r = 0.61), peak CMJ power (male: r = 0.63, female: r = 0.75), and BOMB throw distance (male, r = 0.6; female, 0.6) were positively correlated with CHS in both male and female golfers. These results suggest that the extensor strength of the lower extremities and trunk, centered on the hip joint in the sagittal plane, is important for physical fitness and muscle strength measurement related to CHS. Conversely, concentric trunk rotator strength and CHS were not correlated, suggesting that concentric trunk rotator strength may not be actively involved in CHS.

Genç Voleybolcularda Elastik Bantla Yapılan Bench Press ve Squat Egzersizlerinin Kuvvet ve Sıçrama Performansına Etkisi

Bu çalışmanın amacı, genç erkek voleybolcularda elastik bantla yapılan bench press ve squat egzersizlerinin kuvvet ve dikey sıçrama performansına etkilerini araştırmaktır. Araştırmada 24 sporcu rastgele geleneksel antrenman grubu (GKG, 16.75±1.28 yıl, n=12) ve elastik bant antrenman grubu (EBG, 17.83±1.46 yıl, n=12) olarak ikiye ayrıldı. Voleybolculara sekiz hafta süreyle haftada 2 gün 48 saat arayla sadece bench press ve squat egzersizlerinin elastik bantla yapıldığı yedi kuvvet hareketi içeren antrenman programı uygulandı. Çalışmada squat sıçrama (SS), aktif sıçrama (AS), smaç sıçrama (SMS) yükseklikleri, bench press ve squat hareketlerinin bir tekrar maksimal kuvveti (1 TM), sağlık topu fırlatma mesafesi (STF) ve vücut kompozisyonu ölçüldü. Vücut kütlesi ve vücut kütle indeksi GG’nda EBG’dan daha yüksekti (p&amp;lt;0.05). GG ve EBG karşılaştırıldığında, bench press ve squat 1 TM kuvveti ve sağlık topu fırlatma değerleri arasında anlamlı fark bulunmadı (p&amp;gt;0.05). SS yüksekliği elastik bant antrenman grubunda geleneksel kuvvet antrenman grubundan daha yüksekti (p&amp;lt;0.05), ancak AS ve SMS yüksekliğinde her iki antrenman yönteminin etkisi benzerdi (p&amp;gt;0.05). Sonuç olarak, geleneksel kuvvet antrenmanının vücut kütlesi, yağsız vücut kütlesi ve vücut kütle indeksinde elastik bant antrenmanından daha etkili bir yöntem olduğu görüldü. Bench press ve squat 1 TM kuvveti, sağlık topu fırlatma, AS ve SMS performansında antrenman yöntemlerinin etkilerinin benzer olduğu, elastik bantla kuvvet antrenmanının SS performansında geleneksel kuvvet antrenmanına göre daha etkili olduğu görüldü.

A computational study on the basis for a safe speed limit for bicycles on shared paths considering the severity of pedestrian head injuries in bicyclist-pedestrian collisions

Bicyclists and pedestrians are two large vulnerable groups of road users. Many cities have allowed cyclists to share space with pedestrians on footpaths and off-road paths to reduce conflict with motor vehicles. The risk of bicyclist-pedestrian accidents is also increasing accordingly. Therefore, there is a need to understand the factors that affect the risk of injury in such accidents, especially to pedestrians who are considered more vulnerable. This paper presents a detailed investigation of bicyclist-pedestrian collisions and possible injury outcomes. The study has considered five levels of collision speed ranging from 10 km/h to 30 km/h, three pedestrian profiles (adult, child, and elderly) differentiated by their weight and height, three bicycles with different masses, and five impact directions. The bicyclist-pedestrian collision simulations have been analyzed based on four metrics: throw distance, peak head velocity on impact with the ground, head injury criterion (HIC) value, and the probability of severe head injury. For each simulation, the throw distance and peak head velocity on impact with the ground are extracted. Following that, the HIC and the probability of severe head injury to pedestrians are computed. The results show a significant effect of collision speed (p < 0.05) on all four metrics. The analysis has been further extended to study the effect of height and weight profile, bicycle mass, and impact directions on bicyclist-pedestrian collisions. According to the results, the impact directions largely influence the outcome of bicycle-pedestrian collisions. In general, direct impacts on pedestrian body center have been found to yield higher HIC values and probability of severe head injury to pedestrians than off-center impacts. Also, video analysis of simulated collisions has suggested that the accident mechanism depends on weight and height profiles (correlated with different age groups) and impact directions. Finally, recommendations have been proposed based on the study, including a speed limit of not more than 12 km/h for bicyclists on narrow shared paths and footpaths where risks of collisions with pedestrians are high. The results and analysis presented could be helpful for developing legislation to minimize conflicts between bicyclists and pedestrians on shared paths and to reduce potential injury to pedestrians.

Assessment of Preschool Children’s throwing Ability by throwing Distance and Velocity

A remarkable decrease in children’s throwing ability has recently been reported. Until now, although throwing ability of children has been mainly assessed by distance, velocity has also become easily instrumentally measurable. However, the relationship between the throwing distance and velocity remains unclear. This study examined the age and gender differences in throwing distance and velocity, and their relationship in preschool children. Participants were 270 children (boys: 134, girls: 136), 3–6 year olds. Both the measured values had high reliability (ICC = throwing distance: boys, 0.73, girls, 0.70; throwing velocity: boys, 0.83, girls, 0.78) and were greater in boys than in girls, in 6-year-olds than in 5-year-olds, and in 5-year-olds than in 3- and 4-year-olds. Partial correlation coefficient eliminating age effect was significant (boys: 0.65, girls: 0.53). Correlation at each age was significant and high at 5 and 6 years old (r = 0.70~0.76), but insignificant only in 3-year-old girls. In conclusion, throwing velocity has high reliability, similar to throwing distance, and reflects gender- and age-related differences in preschool children. Although throwing velocity is related to throwing distance, their relationship differs according to children’s gender and age.

Strength Abilities and Serve Reception Efficiency of Youth Female Volleyball Players

Success in volleyball largely depends on motor abilities, particularly on maximum strength, power, jumping, and speed performance. However, a small number of studies assess the relationship between motor abilities and the effectiveness of volleyball technical skills. Therefore, the aim of the study was to assess the impact of the strength of the upper and lower limbs on the efficiency of serve reception during a 2 vs. 2 game, as well as to evaluate the results of motor measurements in the context of determining the usefulness of current testing procedures. The study involved a carefully chosen group of 12 girls aged 12–13 years (body height: 176.5 ± 4.2 cm, body mass: 58.6 ± 5.1 kg, and training experience: 43 ± 15 months) selected for the Lower Silesian Regional Volleyball Team. The following tests were conducted: handgrip strength with a hand dynamometer, bent-arm hang, 2 kg medicine ball throw, shoulder joint internal rotators (IR) peak torque, standing long jump, spike jump, and countermovement jump. The measurements of the shoulder joint IR peak torque were performed under isometric (at 10°, 35°, and 65° rotation angles) and isokinetic (at 60°/s, 180°/s, and 300°/s) conditions. The efficiency of serve reception was evaluated during a 2 vs. 2 games by using Data Volley statistical software. The strongest positive relationships were observed between the serve reception efficiency and the peak torque and power of the shoulder joint IR, the medicine ball throw distance, and handgrip strength. Jumping variables showed no associations with efficient of serve reception. Consequently, we suggest adding protocols to volleyball training that include strength exercises aimed at developing the IR muscle group. The isokinetic upper limb test should be introduced as a valid tool in selection process. Coaches who do not have access to modern research equipment should use the medicine ball throw test to evaluate strength abilities as an alternative assessment of the serve reception efficiency.

Assessment of the Correlation between hand grip strength test and seated medicine ball throw test at 45° angle among physiotherapy students: An Observational Study

Seated Medicine Ball Throw (SMBT)test at 45 degrees throw angle is used to measure the Upper body power. Measurement of grip strength, is an important component in body strength evaluation and can provide us with a quick assessment of an individual’s upper limb strength. Objective To assess the relationship between handgrip strength and upper body power among physiotherapy students via Digital Handgrip Dynamometer and Seated Medicine Ball throw test respectively. Methods: A cross-sectional study was carried out at Shalamar School of Allied Health Sciences, Lahore. This study recruited 45 participants of both gender, age between 18 to 24 years. Peak grip strength of both hands was taken using digital handheld dynamometer in kg. Seated Medicine Ball Throw, also called the medicine ball chest pass was performed by the participants using 2 kg medicine ball. SPSS was used to calculate the correlation of all variables. When the ball is released at 45 degrees, this study found a high association between handgrip strength and Seated Medicine Ball throw distance. SMBT has a mean of 149.7837.14, Right Handgrip Strength has a mean of 21.26kg5.3, and Left Handgrip Strength has a mean of 20.53kg4.69. Results: Grip strength left (r=.0.899) and right (r=.871) were found to have a significant link with Seated Medicine Ball throw (SMBT) performance in Pearson product-moment analysis. The dependent variable, SMBT, and the independent variables, HGS and Height, had a strong positive linear association (r=0.908). Conclusion: A higher Handgrip strength leads to a longer Throw distance, implying that a stronger Handgrip signifies a stronger Upper body.

Prediction of flyrock throw distance in quarries by variable selection procedures and ANFIS modelling technique

This study suggests application of variable reduction procedures for flyrock prediction. It was aimed to create robust and non-complex predictive models. Eleven operational blast parameters and rock mass properties were measured in an aggregate quarry. Dominant parameters for flyrock occurrence were determined by multivariate statistical methods. Two parallel ANFIS models were developed for flyrock prediction. The first ANFIS model was constructed based on the results of stepwise regression. Burden–hole diameter ratio, in-situ block size and specific charge are the input parameters of ANFIS 1. The second ANFIS model was created based on the results obtained by factor analysis. Burden–hole diameter ratio, bench height–burden ratio, number of holes and charge weight are used as input parameters for ANFIS 2. The calculated mean absolute percentage errors are lower than eight percent for the ANFIS predictions. The median absolute errors are lower than 5 m. The study also investigates alternative accuracy measures to evaluate forecasting performance. Standardized errors, normalized errors and Nash–Sutcliffe Efficiency were found to be useful for model validation. It is concluded that more than a single model can be created for a specific site. Pre-statistical analysis for variable reduction increases performance of the predictive models. Burden appeared to be a significant parameter for flyrock throw.

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 &lt; 0.001), three-step throws at a distance between 6 and 9 m (35.9%, p &lt; 0.001), and zero- and one-step throws from 6 m (30.5%, p &lt; 0.001). Likewise, the last step with natural footing is the most used (93.7%, p &lt; 0.001) with a complete cycle of steps, followed by false foot with more than three steps (27.3%, p &lt; 0.001), and two feet with zero steps (12.6%, p &lt; 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.

Modifikasi Prototipe Robot Pelontar Pakan Ikan dan Sistem Monitoring Level Air pada Tambak

Fisheries are one of the sectors that are relied upon for national development. In 2019, the export value of Indonesian fishery products reached Rp. 73,681,883,000, which is an increase of 10.1% from 2018 exports. Marine products such as shrimp, tuna, squid, octopus, crabs and seaweed are sought-after commodities. The development of fish farming can be carried out if the availability of good quality seeds and available in sufficient quantities, proper feed, prevention and treatment of disease and a good living environment. The survival rate at the seed stage is influenced by the type of feed given and the amount according to the needs of the fish. This study aims to modify the previous feed throwing robot so that it can be thrown further and the feed is not destroyed so that it can help the work of fish pond farmers in providing fish feed, modify the tool to help fish pond farmers work in knowing the pond water level, design and build a filling system. manually and automatically using solar panels and modifying the information system on the previous tool so that it can display more information to fish pond farmers. The results showed that the ideal distance of feed throw 5.1 meters, and maximum charging using solar panels 14.28 Watts per hour. The feeding system, water level regulator, information system and charging system can facilitate the pond management process

창던지기 선수들의 경기기록과 운동학적 요인의 관계

The purpose of this study was to investigate the relationship between javelin throw distance and factors affecting throw distance by world class male and female javelin throwers. This involved analysis of results from a total of 34 attempts by top 12 javelin throwing athletes (6 males and 6 females) participating in the 2019 Mokpo Throwing Competition. To achieve the research objectives, three high-speed cameras were used during the competition and analyzed using a three-dimensional analysis program (Kwon3D 3.1). The results show that males had a negative correlation with the horizontal velocity from the time of left foot landing (LC) to the time of right foot landing (RC) during cross-step (r= -.726, p=.01. Conversely, for women, the foot center distance, velocity, and LC-RC value before projection were positively correlated (r=.717, p=.001) appeared. The maximum angle and record of the knee are negatively correlated only in the female record (r= -.532, p=.028). Javelin posture angle and attack angle had negative correlation with record (r= -.489, p=.046; r= -.509, p=.037). For male athletes, the horizontal velocity before projection requires a maximum velocity that does not affect their posture during projection; for female athletes, the higher the velocity, the higher the record, and the higher javelin’s posture angle and attack angle. These results show there was a difference in the record factors between male and female athletes in the javelin throwing record, and guidance considering gender and individual characteristics is required.

Study on the maximum value of flight distance based on the fractional differential equation for calculating the best path of shot put

Abstract From the perspective of physics, this article analyzes the various factors that affect the distance of shot put in the process of actual shot put. Based on the actual situation, it uses fractional calculus and physical formulas to calculate the shot throw distance and to conduct a comprehensive analysis. The experiment confirms that the three factors that affect the shot flying distance are the shot angle, shot speed, and shot height and analyzes the relationship between these three factors and the impact of each univariate on the shot flying distance. The analysis results show that among the three factors, the shot speed has the greatest impact on the flight distance, followed by the shot angle, and the shot height has the least effect; moreover, the optimal shot angle is not a specific value but a general range.

Evaluation of New, Sputtered Carbon SPME Fibers with a Multi-Functional Group Test Mixture

We report the first fabrication of sputtered carbon, solid-phase microextraction (SPME) fibers. These fibers have competitive extraction capabilities compared with the commercial carbon wide range (CWR) SPME fiber. This report also includes a demonstration of a newly developed SPME test mix that includes 15 different compounds with a wide range of functional groups and chemical properties. The fiber fabrication process involves sputtering carbon onto fused silica fibers, and the effects of throw distance on the morphology of the carbon coatings were studied. Four different carbon coating thicknesses were evaluated, with PDMS added as a stationary phase. These fibers were characterized with multiple analytical techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) goniometry, as well as headspace (HS) and direct immersion (DI)–SPME–GC–MS. The best (11.5 µm) sputtered carbon SPME fibers, with and without PDMS, were evaluated using the new evaluation mix and compared with the commercial CWR fiber and a previously sputtered/developed silicon fiber. The new probe mix helped elucidate differences among the fibers, which would have been missed by current commercial test mixes. The sputtered carbon SPME fibers showed similar functional group selectivity as commercial CWR fibers. However, the sputtered carbon fibers showed higher responses per volume compared with the commercial CWR fiber, indicating the porous morphology of the sputtered carbon has the ability to overcome large phase thickness/volume discrepancies and increase the relative recovery for various compounds.

Centre of mass kinematics of the hammer and thrower during different hammer-throwing drills utilised for training

ABSTRACT During elite-level hammer throws, the vertical displacement of the centre of mass (COM) of the thrower and hammer are approximately 180° out of phase (the hammer’s COM is at its high point when the thrower’s COM is at its low point, and vice versa) prior to the hammer’s release. This out-of-phase coordination pattern contributes to the velocity of the hammer, which ultimately contributes to the distance thrown. Several drills are used to improve coordination between the thrower’s and hammer’s COM, but it is not currently known if the out-of-phase pattern is present during these drills. This study examined the relative phase between the COM of the hammer and thrower during two different rotational drills: The Double Hammer Head and Single Arm drills. Using a 12-camera motion analysis system, COM kinematics for both the hammer and thrower were examined for seven NCAA Division I throwers during the two drills. Contrary to their purported purpose, the phase angles between thrower’s and hammer’s COM were significantly different from 180° during both drills. Further research should be conducted to examine the mechanical factors of hammer throwing drills, as well as the effect such drills have when implemented within training programs.

Sprint mechanical properties of professional rugby league players according to playing standard, age and position, and the association with key physical characteristics.

This study determined the influence of playing standard, age, and position on the horizontal force-velocity (FV) properties of rugby league players, and the association with other physical characteristics. This observational study used a cross-sectional study design with a range of physical characteristics recorded from 132 players from 5 Super League clubs. Sprint data was used to derived theoretical maximal force (F<inf>0</inf>) and velocity (V<inf>0</inf>), power (P<inf>max</inf>), maximal rate of force (RF<inf>max</inf>) and the rate of decrease in RF<inf>max</inf> (D<inf>RF</inf>). Differences between playing standard, age groups and playing positions were determined (P value and standardized mean difference [SMD]) along with correlational analysis to assess the relationship between FV properties and key physical characteristics. Senior players reported lower split times (SMD=-0.26-0.59, P=0.002-0.017), and higher absolute F<inf>0</inf>, P<inf>max</inf> and V<inf>0</inf> (SMD=0.47-0.78, P<0.001-0.010). Players aged <21 years reported higher split times and lower absolute F<inf>0</inf> compared to 21-26 years (SMD=-0.84-0.56, P<0.001-0.04) and a lower V<inf>0</inf> than >26 years (SMD=-0.40, P=0.002). Hit-up forwards were slower than outside backs (SMD=-0.30-0.89, P<0.001-0.042), though produced the highest absolute F<inf>0</inf> and P<inf>max</inf>. Sprit times, F<inf>0</inf>, V<inf>0</inf>, P<inf>max</inf> and RF<inf>max</inf> were associated with change of direction and countermovement jump performance, whilst FV<inf>slope</inf> and D<inf>RF</inf> were associated with countermovement jump performance only. F<inf>0</inf> and P<inf>max</inf> were associated with medicine ball throw distance (r=0.302-0371, P≤0.001). There was no association with prone Yo-Yo IR1 distance (r=-0.16-0.09, P=0.060-0.615). These results provide insight into the horizontal FV properties with reference to key subgroups and highlights several associations with other characteristics across large sample of rugby league players. The result of this study should be used when interpreting the sprint ability of rugby league players, planning the long-term development of youth players, and inform program design for all.