Throw Distance Research Articles

A kinematic analysis of the two types of soccer throw-in techniques

This study aimed to identify kinematic variables in two soccer throw-in techniques, examine their relationship to throw distance, and explore differences based on technique. A descriptive approach was used, with a purposive sample of 15 first-grade players from the Hussein Youth Club. Each player performed both types of throw-in techniques, recorded at 60 f/s using a Nikon D3400 camera placed laterally. A total of 30 successful attempts were analyzed using Kinovea 0.8.27 x64. Variables studied included foot distance, skill duration, release velocity and angle, and ball release height. Data were analyzed with SPSS. The results revealed weaknesses in the side throw-in technique, such as a low release angle, though better distances were achieved with the second technique. Significant correlations were found between foot distance, release angle, release velocity, vertical velocity, and throw distance (p<0.05). There were also statistically significant differences in knee angle, moment of throw, and throw distance, favoring the second technique (p<0.05). The sample's technique shows several weaknesses impacting performance. Projectile variables strongly influence throw distance, closely linked to various kinematic factors. Moreover, the throw-in method is crucial in determining the overall distance.

Minimal influence of the menstrual cycle or hormonal contraceptives on performance in female rugby league athletes.

We examined performance across one menstrual cycle (MC) and 3weeks of hormonal contraceptives (HC) use to identify whether known fluctuations in estrogen and progesterone/progestin are associated with functional performance changes. National Rugby League Indigenous Women's Academy athletes [n=11 naturally menstruating (NM), n=13 using HC] completed performance tests [countermovement jump (CMJ), squat jump (SJ), isometric mid-thigh pull, 20m sprint, power pass and Stroop test] during three phases of a MC or three weeks of HC usage, confirmed through ovulation tests alongside serum estrogen and progesterone concentrations. MC phase or HC use did not influence jump height, peak force, sprint time, distance thrown or Stroop effect. However, there were small variations in kinetic and kinematic CMJ/SJ outputs. NM athletes produced greater mean concentric power in MC phase four than one [+0.41W·kg-1 (+16.8%), p=0.021] during the CMJ, alongside greater impulse at 50ms at phase one than four [+1.7N·s (+4.7%), p=0.031] during the SJ, without differences between tests for HC users. Among NM athletes, estradiol negatively correlated with mean velocity and power (r=-0.44 to -0.50, p<0.047), progesterone positively correlated with contraction time (r=0.45, p=0.045), and both negatively correlated with the rate of force development and impulse (r=-0.45 to -0.64, p<0.043) during the SJ. During the CMJ, estradiol positively correlated to 200ms impulse (r=0.45, p=0.049) and progesterone to mean power (r=0.51, p=0.021). Evidence of changes in testing performance across a MC, or during active HC use, is insufficient to justify "phase-based testing"; however, kinetic or kinematic outputs may be altered in NM athletes.

Influence of car front-end designs on motorcyclists’ trajectory in head-on and side-on-head crashes

Motorcyclists are highly vulnerable road users, and cars are one of their primary crash opponents. This study investigates the influence of car front-end designs on motorcyclist trajectory in head-on and side-on-head crashes. The analysis is based on a dataset of 120 multi-body crash simulations conducted using MADYMO and post-processed with MATLAB. An analysis of 1412 real-world Powered Two-Wheeler (PTW) to car accidents was conducted to determine the most common crash configurations and the associated ranges of the variables, such as vehicle speeds and contact points. Three PTW styles (sport-touring, scooter, and sport) and four car front-end designs (Sport utility vehicle (SUV), Family Car/Sedan (FCR), Roadster (RDS), and Multi-purpose vehicle (MPV)) were considered.The study examined the riders’ thrown distance in both collision types. It was observed that, regardless of the collision type, the head was identified overall as the primary body region coming into contact with the opposing vehicle, followed by the chest and neck. In frontal collisions, an augmented bonnet height corresponded to an increased incidence of head contact, whereas a lower bonnet height resulted in a higher frequency of chest contact. Moreover, the thrown distance depended also on PTW speed, particularly for sport and sport-touring motorcycles. Notably, contact with the car windscreen was only observed at velocities exceeding 60 km/h, whereas impact with the bonnet leading edge occurred exclusively below this threshold. Due to the shielding effect of their PTW’s fairing, scooter riders predominantly experienced no contact with the opposing vehicle. Sport-touring motorcycles exhibited a more vertical trajectory upon ejection, leading to a greater likelihood of overturning and subsequent rearward head impact with the vehicle. In contrast, sport motorcycles tended to forward projections with a high likelihood of chest contact. In the case of lateral impacts, it was observed that vehicles with a more prominent profile, such as SUVs and MPVs, equipped with protruding bumpers, effectively restrained riders. In this case, vehicle speed did not exert a significant influence on the thrown distance. Additionally, the presence of a conspicuous fuel tank and the initial posture of the rider on the PTW played a crucial role in determining the final thrown distance. Due to their upright postures and the absence of a pronounced fuel tank, scooter dummies were thrown further than others, thus causing head contact with the windscreen.These findings highlight the importance of car front-end design and PTW fairings in mitigating riders’ injuries and provide valuable insights to vehicle manufacturers for developing tailored safety measures for riders.

The relationship between ball mass and throw distance: Implications for coaching practice

In training for many sports, balls of different masses are thrown. This study examined how ball mass influences distance thrown. Based on geometric scaling principles a relationship was derived between ball mass and throw distance: throw distance was inversely proportional to ball mass. This relationship was tested in two ways. The first approach was using athlete shot put throw distances with different shot masses, and hammer throws performed with different mass hammers. These experimental data were better represented by the non-linear relationship, derived from geometric scaling principles, than assuming a simple linear relationship. The second approach was to use a simulation model to predict throw distance for balls of different masses. The model contained realistic segmental inertial properties, activation dynamics, moment-joint angle properties, and moment-joint angular velocity properties. The non-linear relationship provided a better fit to the results of the simulations compared with a linear model. The experimental and modeling results support the theoretical relationship derived between distance thrown and ball mass. The relationship has utility for coaches monitoring and planning the training of athletes which incorporates throwing different mass balls.

Can resistance training improve throwing performance in handball players? A Systematic review and meta-analysis

BackgroundThrowing is one of the most important movement in handball. Throwing performance is crucial for success in handball.ObjectiveΤo investigate the level of evidence for the effect of resistance training (RT) on throwing performance in handball players.MethodsSystematic searches of Pubmed, Medline complete, Cinahl, Sport Discus and Scopus were undertaken for peer reviewed articles published between 18 March 1995 to 18 March 2023. Randomized, controlled, clinical studies, written in English, aiming to investigate the effect at least one modality of RT on throwing performance (velocity or/and accuracy) in handball players were considered for inclusion in the study. The eligible studies were assessed for methodological quality using the Physical Therapy Evidence Database (PEDRO) scale. The Best Evidence Synthesis (BES) approach was used for synthesizing and reporting the results. Furthermore, the random-effects model was used for the meta-analysis and the Q-statistic was used to test the null hypothesis that all studies in the analysis share a common effect size.ResultsOne hundred ninety-eight studies were identified, of which 30 were included. A total of 727 handball players (males = 388, females = 292) were included. 28 of the 30 studies were rated as high methodological quality studies (PEDRO score > 70%) while the rest of the studies were rated as moderate methodological quality studies (PEDRO score ≤ 60%). The mean effect size for the effectiveness of resistance training (RT) in improving jumping throw, running throw, and standing throw velocity were 1.128 (95% CI 0.457 – 1.798), 1.756 (95% CI 1.111 – 2.400), and 1.098 (95% CI 0.689 – 1.507) correspondingly. Traditional weight training using barbells in mostly compound lifts yielded the most significant and robust results. Other RT modalities such as elastic bands, medicine balls, core training and ballistic training showed no significant results or positive effects due to the limited number of the studies.ConclusionStrong evidence exists only for the effectiveness of RT using barbells in increasing throwing velocity. In contrast, the remaining RT modalities, while yielding positive results, have limited support due to limited number of studies and the high heterogeneity between studies. Furthermore, there is insufficient evidence to support various forms of RT in increasing throw distance. Finally, medicine ball training and elastic band training demonstrated no benefits in improving throwing accuracy.Trial registrationPROSPERO ID: CRD42023393574.

Relationships between throwing distance and physical strength in female hammer throw: Estimating physical strength requirement corresponding to throwing distance

The purpose of this study was to clarify the relationships between female hammer throwers’ physical strength and their throwing performance and to create standard values corresponding to throwing distance. Eighty-two female hammer throwers, with the throwing distance ranging from 30.31 to 63.82 meters, participated in this study. The questionnaire was designed to collect data on physical strength. Pearson's product-rate correlation coefficient was used to examine the relationship between each item and the throwing distance. A single regression analysis was performed with each item which was significantly correlated to the throwing distance as the dependent variable and the throwing distance as the independent variable to estimate the standard values corresponding to throwing distance. The results showed that all physical strength variables, except for 30 m sprint, were significantly correlated with the throwing distance, with weight training variables having the higher correlation coefficients. In addition, standard values corresponding to throwing distance were obtained using a single regression analysis.

A Comparative Study on the Effectiveness of Shoulder Tap Push-up and Half Kneeling Press in Distance Throwing among Amateur Cricket players

Objective: To find out the effect of shoulder tap push up with grip strengthening in distance throwing among cricket players and to find out the effect of half kneeling shoulder press with grip strengthening in distance throwing among cricket players. Materials and Method: 110 voluntary participants were recruited according to the selection criteria and were randomly allocated to Group A shoulder tap push up exercise (n=55) and Group B half kneeling shoulder press exercise (n=55). The exercise program underwent training for 30 min, 4 times per week for 4 weeks. Result: When post values of Group A for hand dynamometer i.e., 39.98 ± 12.461 and Group B i.e.; 47.21 ± 8.841 was compared there was improvement in group B as compared to Group A the p-value was extremely significant that is (0.0001). When post value of group A and Group B for 2 kg medicine ball were compared i.e., 4.51± 1.259 and 5.45 ± 1.044 there was improvement seen in group B as compared to group A with an extremely significant p value of (0.0001). Conclusion: The results from the present study are very encouraging and demonstrate the benefit of half kneeling shoulder press with grip strengthening over shoulder tap push up with grip strengthening in improving throwing distance. Thus, half kneeling shoulder press can be incorporated into training programs of cricket players for enhancing their performance levels.

A proposed equation for calculating the total horizontal distance in projectiles of varying launch and landing levels

Background The projectile draws a path for the flight of the tool, a horizontal distance can be calculated according to the Galileo Galilei Law of Projectiles (GGLP), but only if the two points of the launch and fall of the tool are equal, otherwise we need an equation to be added to the (GGLP) to calculate the real distance that was generated due to the difference between the launch and fall points. There are several equations to calculate this, but they are complex and can be simplified. Methods The proposed equation was tested by exporting samples from three different throwing events (javelin, shotput, disc) data in track and field games, to calculate the horizontal throwing distance. The proposed equation was based on the basics of mathematics and geometry. The equation was tested in terms if the height is zero, the proposed equation is suitable even for projectiles with equal levels, and the credibility of the proposed equation with the previous equation was tested statistically. Results It was found that there were no differences between the two equations (p&gt;0.05). and due to the relative ease of access of the proposed equation to very similar results, researcher suggests applying the proposed equation. Conclusions The proposed equation contained the height factor in the previous equation, and when tested by several criteria, the proposed equation has proven its credibility, statistically and graphically. The ranges of theoretical achievement calculated by the proposed equation are often closer to the real achievements.

New model of linkage evolution for the transtensional fault systems in the Nanpu Sag of Bohai Bay Basin: Insight from seismic interpretation and analogue modelling

The evolution of faults within the same stress field is frequently influenced by numerous factors, involving the reactivation of pre-existing structures, stress transmission through ductile detachment layers, and the growth, interaction, as well as linkage of new fault segments. This study analyses a complex multi-phase oblique extension fault system in the Nanpu Sag (NPS) of the Bohai Bay Basin (BBB), China. High-resolution three-dimensional (3D) seismic data and analogue modelling indicate that the oblique extensional reactivation of pre-existing structures governs the sequential arrangement of fault segments in the caprock, and they dip synthetically to the reactivated fault at depth. During the NW–SE extension in the Eocene, the predominant movement of the pre-existing fault is strike-slip. Subsequently, during the N–S extension since the Oligocene, inclined at 20° to the pre-existing fault, forming splay fault segments and ultimately creating large en-échelon arcuate faults linked by relay ramps. Using fault throw-distance (T-D) and laser scanning, we reconstructed the fault evolution model of oblique extension reactivation in the presence of a ductile detachment basement. Our study illustrates that the arcuate faults can be categorized into linear master fault segments controlled by pre-existing structures, bending splay faults in the termination zone, and normal fault segments responding to the regional stress field. The interaction between faults occurs among normal faults and strike-slip faults, and the kinematic unification of the two fault systems is accomplished in the intersection zone. As the faults continue to evolve, the new fault segments tend to relinquish the control of pre-existing structures and concentrate more on the development of planar and continuous major faults. The ductile detachment layer significantly contributes to the uniform distribution of strain, resulting in narrow shear zones and discontinuous normal faults in its absence.

Impact of Velocity of Detonation and Charge per Bank Cubic Meters on Flyrock Throw Prediction Using Support Vector Machine

One of the ambient effects of production blasting is flyrock. To effectively manage flyrock throw distance in mining, there is the necessity to successfully envisage blasting output without sacrificing the hazardous impact of flyrock which may result in fatality and operational shutdown. For flyrock throw distance prediction, velocity of detonation (VOD) and charge per bank cubic meter (CPBCM) are not usually included. This paper focuses on the use of support vector machine (SVM) regression to ascertain the impact of VOD and CPBCM on flyrock throw predictions. The machine learning models were linear support vector machine (LSVM), quadratic Gaussian support vector machine (QGSVM), fine Gaussian support vector machine (FGSVM), medium Gaussian support vector machine (MGSVM), and cubic Gaussian support vector machine (CGSVM). The outcome indicates that FGSVM was the most sensitive with a 4% improvement when VOD and CPBCM were included. As a result, the LSVM model provides a suitable AI competitive alternative tool for flyrock throw prediction in mining operations by incorporating VOD and CPBCM.

Changes in strength-related outcomes following velocity-monitored resistance training with 10 % and 20 % velocity loss in older adults

We compared the effects of velocity-monitored resistance training with an intra-set velocity loss (i.e., the decrement in repetition velocity over the set) of 10 % vs. 20 % on strength-related outcomes in older adults. We randomly assigned eighteen older adults to a velocity loss group of 10 % (n = 10; 78 ± 12 years) or 20 % (n = 8; 73 ± 10 years) to perform a 10-week training program. The primary outcomes were the one-repetition maximum (1RM) and the average mean velocity against absolute loads associated with loads <60 % 1RM (MVlow) and ≥ 60 % 1RM (MVhigh) in the leg and chest press exercises, assessed at pre-, mid- (week 5), and post-test. Secondary outcomes included handgrip strength, 1-kg medicine ball throw distance, 10-m walking time, and five-repetition sit-to-stand time. No differences between groups were found in any outcome at any time (p > 0.05). Both groups improved the 1RM leg press from pre- to mid- and post-test and the MVlow and MVhigh from pre- to mid-test (p < 0.05). No group improved the 1RM chest press (p > 0.05), but both increased the MVlow from pre- to mid-test (p < 0.05). Furthermore, both groups improved the sit-to-stand time, while only the 20 % velocity loss group significantly improved handgrip strength and 10-m walking time (p < 0.05). The results showed that both velocity losses improved leg press strength and velocity, chest press velocity, and sit-to-stand time in older adults, although a 10 % velocity loss was more efficient as it required less volume (i.e., total repetitions) than 20 %. Nevertheless, the latter seems required to optimize handgrip strength and 10-m walking time in older people.

Effect of Simultaneous Intervention in Kindergarten and Home to Improve Ball Skills

This study examines the effectiveness of a simultaneous intervention in kindergarten and home to improve ball skills in children. Two kindergartens in Ibaraki, Japan, were divided into intervention (N = 98, mean age = 5.5 [0.6] years) and control groups (N = 88, mean age = 5.6 [0.6] years). The intervention was for 4 weeks. Parents received emails with video URLs for four ball activities once a week, and they undertook the activities introduced in the video at home with their children. Before the intervention, a 60-min workshop was held for kindergarten teachers. Ball skills (distance thrown and percentage of ball catches) were assessed pre- and postintervention. Two-way repeated measures analysis of variance and multiple regression analysis were used to compare the groups and explore the factors related to the improvement of ball skills. As a result, although throwing skills did not change significantly in both groups, there was an increase in the frequency of ball activity at home and perceived change of batting skills, both of which were associated with postthrowing skills. Catching skills improved significantly only in the intervention group; however, no significant factors related to the improvement of these skills were found. Our study demonstrates that simultaneous intervention in kindergarten and home may contribute to improve catching skills over a short period of time.

Integrating Resistance Training Into Secondary School Physical Education Lessons: Effects of a 6-Week Intervention on Athletic Motor Skill Competencies.

The purpose of this study was to examine the effects of resistance training (RT) in physical education lessons on athletic motor skill competencies in secondary school children. Seventy-eight males were randomized into experimental year groups or a control group. Experimental groups participated in RT during physical education lessons for a 6-week half-term. The control group continued with their games-based curriculum. Countermovement jump (CMJ) height, seated medicine ball throw (SMBT) distance, and RT skills battery scores were measured preintervention and postintervention. All experimental groups significantly improved SMBT distance and RT skills quotient (P < .05). All intervention year groups also significantly improved CMJ height (P < .05), except for year 9. Although the control group did not show improvements in CMJ height and RT skills quotient, there was a significant improvement in SMBT distance (P < .05). The year 7 and 8 males exhibited greater improvements in CMJ height and SMBT distance (d = 0.21-0.79) than in year 9 (d = 0.00-0.40). Results of the study indicated that a 6-week half-term RT intervention in physical education lessons can improve athletic motor skill competencies (P < .05, d = 0.21-2.51) in male youths.

Influence of trunk rotator strength on rotational medicine ball throwing performance.

The strength of the trunk musculature plays an essential role in performance. The aims of this study were to analyze the relationship between the strength of the trunk rotation muscles with rotational medicine ball throwing velocity and distance, to study differences between sex in rotational medicine ball throwing and to compare the asymmetries of trunk rotational strength and rotational medicine ball throwing. Thirty physically active college students participated on the study. Horizontal and low cable woodchop exercises were assessed with a functional electromechanical dynamometer and throwing was measured with a radar and a measuring tape. A Pearson's correlation coefficient was calculated for the relation between trunk rotational strength and rotational medicine ball throwing. Independent samples t-test was performed to determine the differences between sex in rotational medicine ball throwing and a paired samples t-test was performed to study the asymmetries. Large and very large correlations were obtained between trunk rotational strength and rotational medicine ball throwing (r=0.68-0.79). Significant differences and a large effect size were found between males and females for all throwing velocity and throwing distance variables (P<0.05; ES>0.90) and asymmetries in performance of mean velocity throwing (P=0.003; ES=-0.60) and peak velocity throwing (P=0.025; ES=-0.43). No significant differences were found between dominant and non-dominant side in any of the trunk rotator strength assessment conditions (P>0.05). There is a large or very large correlation between the STRM and the RMBT in all its modalities. Differences in strength were found between sexes, with no significant differences between dominant and non-dominant sides.

A proposed equation for calculating the total horizontal distance in projectiles of varying launch and landing levels.

The projectile draws a path for the flight of the tool, a horizontal distance can be calculated according to the Galileo Galilei Law of Projectiles (GGLP), but only if the two points of the launch and fall of the tool are equal, otherwise we need an equation to be added to the (GGLP) to calculate the real distance that was generated due to the difference between the launch and fall points. There are several equations to calculate this, but they are complex and can be simplified. The proposed equation was tested by exporting samples from three different throwing events (javelin, shotput, disc) data in track and field games, to calculate the horizontal throwing distance. The proposed equation was based on the basics of mathematics and geometry. The equation was tested in terms if the height is zero, the proposed equation is suitable even for projectiles with equal levels, and the credibility of the proposed equation with the previous equation was tested statistically. It was found that there were no differences between the two equations (p>0.05). and due to the relative ease of access of the proposed equation to very similar results, researcher suggests applying the proposed equation. The proposed equation contained the height factor in the previous equation, and when tested by several criteria, the proposed equation has proven its credibility, statistically and graphically. The ranges of theoretical achievement calculated by the proposed equation are often closer to the real achievements.

Shoulder vibratory exercises improves shoulder external rotation muscle strength and shoulder function: Randomized comparison trial.

Based on electromyography measurements, shoulder vibratory exercises efficiently stimulate shoulder muscles activity. Yet very few studies have supported that shoulder vibratory exercises increased shoulder muscles strength and function, and the noninferiority compared with conventional elastic resistance exercises remains unknown. This study investigated the effect of vibratory exercises versus conventional elastic resistance exercises with elastic bands on shoulder external rotation muscles strength and functional performance in young adults. 26 young adults (7 males and 19 females, with age 23.89 ± 3.02) were recruited and randomly allocated to shoulder vibratory exercises with FLEXI-BAR (FLEXI-BAR group) or conventional resistance exercises with elastic band (TheraBand group) for 3 times/week, 4 weeks totally. Shoulder external rotator muscles strength test and Underkofler softball distance throw test (USDTT) were performed before and after the training period. After 4 weeks training, shoulder external rotator muscles strength increased 22.25 ± 15.06 N (P= 0.004, effect size = 1.48) within FLEXI-BAR group and 22.81 ± 14.94 N (P= 0.007, effect size = 1.53) within TheraBand group. There were no statistically significant differences between groups in the three muscle strength tests (P> 0.65). Regarding shoulder function, FLEXI-BAR exercises increased the throw distance 0.81 ± 0.92 meters in USDTT (P= 0.041, effect size = 0.88) while TheraBand exercise did not (P= 0.284), yet there was no statistically significant between group effects (P= 0.608). These findings suggest that shoulder vibratory exercises can improve shoulder muscles strength in young adults and can be a useful alternative to the conventional elastic resistance exercises to improve the shoulder muscles strength and function. This provides therapists with more options in terms of choosing training equipment for rehabilitation programs.

Heating and ventilation performance investigation of a novel linear slot diffuser with adaptive outlet area for near window applications

The linear slot diffuser has ideal cooling performance for near-window applications, and is used for ventilation by utilizing the coandă effect in some cases. However, it has insufficient throw distance due to buoyancy impact during heating periods. And airflow near window surfaces increases convection heat transfer, resulting in extra HVAC energy consumption. Our research focuses on a prototype linear slot diffuser with an adaptive outlet area. Two deflection panels are installed for adjusting the outlet area depending on temperature or usage scenarios. Supply air has a low velocity and wide diffusion range when the panels are open. It can utilize the coandă effect as well as keep convection heat transfer within an appropriate range. Closing the panels will halve the supply area and completely change airflow diffusion and turbulence characteristics. This is considered suitable for heating, but the mounting location needs to be re-evaluated. Therefore, this prototype's heating and ventilation performance is numerically investigated using a low-Reynolds number turbulence model with fine meshes. Temperature, airflow, tracer gas distribution in a typical office space, and the ADPI, DR, and age-of-air indexes are compared before and after outlet area adjustment. Diffuser mounting locations and exhaust methods are also altered to balance heating and ventilation efficiency. As a result, a proper installation location for this prototype is suggested. The adaptive supply area significantly improved this terminal's heating and ventilation performance. Temperature stratification was reduced to a maximum of one-tenth, and impinging jets or displacement ventilation were observed in some cases.

Effect of integrative neuromuscular training and detraining on performance indices in young female volleyball players.

Aim of this study was to determine the effect of: 1) integrative neuromuscular training (INT); and 2) detraining on power and skill performance indices in young female volleyball players. Sixty-one pre- and early pubescent female volleyball players participated in this study divided into two groups, integrative neuromuscular training (INTG) and control (CG). The INTG followed a 12-week INT program twice weekly and both groups participated in volleyball training sessions. During 8-week detraining, both groups keep practicing volleyball. Participants were assessed on upper and lower limb power and skill accuracy tests prior, at the end and 8 weeks after INT. A repeated measures Analysis of Variance was used to examine groups' changes in performance for each variable and significance level was set at P<0.05. INTG improved all power parameters more than CG after 12 weeks of INT (significant interaction, P<0.001) whilst the CG improved only countermovement jump (CMJ) height (P<0.05) and medicine ball (MB) throw (P<0.05). Both groups improved their technical skills accuracy (P<0.001) with INTG presenting higher improvements (P<0.001). During detraining, INTG maintained performance gains in CMJ and Cod (P<0.001). MB throw distance and technical skills accuracy kept on improving for both groups (P<0.01) with higher improvements observed in INTG (P<0.001). INT may cause improvements in specific power and skill performance indices during in season training in young female volleyball players which may be maintained or even improved for at least 8-week detraining when players remain active through volleyball training.

Study of the Group Vibrational Detachment Characteristics of Litchi (Litchi chinensis Sonn) Clusters

A high-speed camera was applied to observe the shaking detachment tests with ‘Guiwei’ litchi clusters using 7 Hz, 9.5 Hz, and 12 Hz and the amplitudes of 40 mm, 60 mm, and 80 mm. The fruit’s detachment time and the number of fruit–fruit impacts were affected by the vibrational parameters and the fruit position (inside or outside of the cluster). A high and stable detachment speed and a low number of impacts could be achieved with the parameter combination of 9.5 Hz/80 mm. The cluster index, considering both the shaking position and the total fruit mass, was found to have a stronger correlation with the detachment time than the average fruit-to-shaker distance (distance from the shaker to the fruit). Thus, the detachment time can be estimated based on the cluster indexes. The fruit-to-shaker distance also affected the fruit-to-shaker impact. A fruit-to-shaker distance of 50~60 mm was recommended to avoid almost all the impacts, depending on the shaking parameters. The horizontal throw distance of the fruit was calculated based on the detachment velocity and angle, which can be used as the design basis for the catching devices. With a high enough drop height, a disc-shaped catching surface with a radius of 475 mm, 489 mm, 591 mm, 741 mm, 844 mm, and 832 mm, respectively, could collect 90% of all the fruit at six different vibrational parameter combinations. A closer catching surface to the fruit could effectively reduce the horizontal throw distance.

Effect of 12-week sports intervention programme on physical fitness and sports performance in individuals with spinal cord injury

Objectives: Inactivity in individuals with spinal cord injury (SCI) results in low physical fitness, cardiopulmonary endurance and poor quality of life. Sports participation is known to enhance physical fitness. Therefore, the present study evaluated effect of a structured, 12-week MGM Sports Intervention for Sports Intervention Program for SCI (SPISI) on physical fitness and throw-ball performance in individuals with SCI. Materials and Methods: The study was conducted at MGM School of Physiotherapy and Spinal Cord Injury Rehabilitation centre in Navi Mumbai, India. Following ethical approval, 15 individuals with SCI (80% males and 20% females mean age 33.1 ± 7.2 years) were recruited. Upper-extremity explosive power (medicine-ball-throw), agility (t-test), cardiorespiratory endurance (incremental shuttle wheelchair propulsion test) and ball-throwing capacity (maximal-pass test) were evaluated pre- and post-12-week sports intervention programme (SPISI). The protocol involved strength training of upper extremity training at 50% 1 repetition maximum and participation in throw-ball sport. Results: Following training, increase in upper extremity explosive power (11%), cardiopulmonary endurance (5%), agility (8%) and ball-throwing capacity in distance (7%) (P &lt; 0.05) was observed. The large effect size was observed for sports performance (maximal-pass test distance-Cohen’s d 1.261), moderate for cardiorespiratory endurance (incremental wheelchair propulsion test distance Cohen’s d 0.517) and upper extremity explosive power (medicine-ball throw distance 0.593). Increment in all outcome variables was greater than minimal clinically important difference. Conclusion: Sports intervention programme (SPISI) for 12 weeks brought about minimal clinically important difference in upper-extremity explosive power, agility, cardiorespiratory endurance and sport-specific performance and should be included as an integral component of rehabilitation of individuals with SCI.