Prediction of Jumping Distance Using Run-Up Velocity and Age for Female Long Jumpers

It is the flight distance which is approximately ninety percent of jump distance in long jump. On the other hand, there are many biomechanical factors that determine the flight distance and horizontal velocity is considered to be the most effective factor. The aim of this study was to create a jump distance estimation model based on run-up velocity that can practically be used by trainers. The research data was included 858 valid trials of 156 female Turkish long jumpers (ages: 17.8±3.4 years). According to the correlation results of the current study; a nonlinear regression model was used between the variables found to have the highest correlation (age, last 10 meter run-up velocity, jump distance). According to this model, 79.10% of the jump distance can be estimated with the variables of age and run-up velocity in the last ten meters. Developed to be used for female long jumpers at a broad performance level, this model may make it possible to make technical evaluations about whether the velocity, technique and strength of a female long jumper are stable. Keywords: long jump, velocity, age, prediction model

The Physical Fitness Effects of a Week-Long Specialist Tactical Police Selection Course

Specialist police tactical teams, like special operations military personnel, are tasked with dangerous, high risk missions which are beyond the scope of general police. Consequently, the selection courses for entry into these teams are physiologically and psychologically demanding. The purpose of this study was to examine the physiological effects of a five-day selection course to aid in candidate preparation and course planning. Measures included body mass, grip strength, sit-and-reach flexibility, and a vertical jump assessment. Eleven candidates finished the selection course with significant decreases in body mass (−2.05 kg, p = 0.006 (95% CI = 3.65–0.45)), grip strength in the right (−14.48 kg, p < 0.001 (95% CI = 21.32–7.64)) and left (−14.27 kg, p < 0.001 (95% CI = 21.89–6.66)) hands and in sit-and-reach flexibility (−6.64 cm, p < 0.001 (95% CI = 9.94–3.33)). No significant decreases in power output or peak jump velocity of 669.77 W (95% CI = 1942.92–603.39) and 0.28 m/s (95% CI = 0.69–0.14) were found and a non-significant, overall increase in vertical jump height of 6.09 cm (95% CI = −6.08 to 18.79) was seen. Decreases in body mass, grip strength and lower limb flexibility are evident in a grueling five-day selection course. Individuals planning on attending these courses should plan for these negative effects and build redundancy into their performance to minimize the effects of fatigue, decrease injury risk and maximize chances of completion.

Efecto de un programa de natación en la condición física de preescolares (Effect of a swimming program on physical condition of preschoolers)

La promoción la actividad física es de especial importancia en la salud de la población, siendo esencial fomentarla en la etapa preescolar. La natación es una elección habitual, pero son escasas las investigaciones que han valorado su efecto en la condición física de los niños. Este estudio tuvo como objetivo describir los cambios observados en la condición física de un grupo de prescolares (n= 47; rango edad=5-6 años), tras participar en un programa de natación. Se formaron dos grupos de niños y niñas en edad prescolar. El grupo experimental (n=24; 29,2% niñas) participó en un programa de iniciación a la natación organizado a razón de dos sesiones de 40 minutos por semana, durante diez meses. El grupo control (n=23; 34,8% niñas) siguió con su actividad habitual. Se valoró el peso, talla, Índice de Masa Corporal, Capacidad cardiorrespiratoria (“Test de los tres minutos”), fuerza explosiva (“Salto horizontal”), velocidad (20 m), agilidad (“Shuttle-run”) y flexibilidad (“V sit”). Se analizaron los datos de un total de 47 niños y niñas. Se hallaron cambios significativos en la capacidad cardiorrespiratoria (p=0,04) y en la fuerza (p=0,031) en los niños del grupo experimental. La agilidad (p=0,022) y la flexibilidad (p<0,001) mejoraron significativamente en los niños pertenecientes al grupo control. El participar en un programa de natación mejoró significativamente la capacidad cardiorrespiratoria y la fuerza de miembros inferiores en niños en edad prescolar.Abstract. Promotion of physical activity is important for community health; thus, it is essential to foment it during the preschool stage. Swimming is one of the common choices, but research assessing its effects on children’s physical condition is scarce. This study aimed at describing the changes in physical condition of a group of preschoolers (n=47; age range= 5-6 years), after performing a swimming program. Two non-randomly-assigned groups of preschool children were formed. The experimental group (n=24; 29.2% girls) took part in a swimming initiation program, carried in two 40-minute sessions per week during 10 months. The control group (n=23; 34.8% girls) continued its usual activity. Weight, height, Body-Mass Index, cardiorespiratory capacity (“Three minute run”), explosive strength (“Horizontal jump”), velocity (20 m), agility (“Shuttle-run”), and flexibility (“V-sit”) were assessed. Data from a total of 47 children was analyzed. Significant changes were observed in cardiorespiratory capacity (p=0.04) and strength (p=0.031) in the experimental group, as well as in agility (p=0.022) and flexibility (p<0.001) in the control group. Taking part in a swimming program significantly improved the cardiorespiratory capacity and strength of the lower body in preschool children. Further research employing randomized controlled trials is needed with the objective of monitoring children’s development level, as well as the physical activity they perform in their free time and therefore confirm these results.

The Influence of Match-Day Napping in Elite Female Netball Athletes

Purpose: To assess the effect of match-day napping and duration of naps on perceptual and performance indices in elite female netball players over 2 consecutive netball seasons. Methods: A total of 14 elite female netball athletes (mean [SD]; age = 23 [6] y) participated in an observational study over 26 competition matches. On each match day, athletes provided information on their napping habits and perceived energy levels, then performed 3 countermovement jumps 3 h:30 min prior to the start of the match. One hour after the match, subjective player performance ratings from the players and 2 members of the coaching staff were obtained. Naps were characterized into 3 conditions for analysis: no nap (NN), <20-min nap (SHORT), and ≥20-min nap (LONG). Results: A significant difference in peak jump velocity was observed between the SHORT and the NN condition in favor of the shorter nap (3.23 [0.26] and 3.07 [0.36] m·s−1, respectively, d = 0.34, P < .05). A moderate, significant difference (d = 0.85; P < .05) was observed for the coach rating of performance (out of 10) between the SHORT and the NN condition (7.2 [0.8] and 6.4 [0.9], respectively) in favor of SHORT. Conclusions: The findings from the study would suggest that a short nap (<20 min) on the day of competition can enhance jump velocity and improve subjective performance in elite netball players, as assessed by coaching staff.

Comparison of Power, Velocity and Force Parameters during Loaded Squat Jump Exercise in the Handball and Arm Wrestling Players

The purpose of this study was to compare power, velocity and force parameters during loaded squat jump (SJ) exercise in the handball and arm wrestling players. In accordance with this purpose, ten arm wrestling athletes from the Turkish National Team (age: 20,7 ± 3,05 years; height: 175,2 ± 5,55 cm; weight: 71,7 ± 8,17 kg) who had ranks in competitions at World and Europe Am Wrestling Championships and ten handball players (age: 23,0 ± 4,00 years; height: 182,3 ± 6,06 cm; weight: 77,8 ± 11,3 kg) who competed at Turkish handball 1st league participated voluntarily in this study. Subjects were performed loaded SJ exercise using a load equals to 40 % of their body weight and obtained the power, velocity and force values using an isoinertial measurement system (T-Force Dynamic Measurement System). For data analysis, descriptive statistic and Mann Whitney - U analyses were used. According to analysis results, there was a statistically significant difference between jump velocity during loaded SJ of handball players and arm wrestling athletes (p < 0.05). Accordingly, arm wrestling athletes have better jump velocity than handball players in terms of mean velocity (MV) and peak velocity (PV). In addition, it was obtained that there wasn’t a statistically significant difference between handball and arm wrestling players in terms of mean force (MF), mean propulsive force (MPF), peak force (PF), peak power (PP), mean propulsive power (MPP), mean power (MP), time and moving distance to barbell bar during loaded SJ (p > 0.05). Consequently, jump ability is a crucial performance indicator in many sports that require explosive actions and the lower-body muscular power. However, it is not a true approach that athletes competing at sport branches which jump ability is an important performance indicator can display a better performance during loaded SJ.

The effects of interventions implemented during a rehabilitation camp on changes in motor skills parameters and body mass in patients with simple obesity

Introduction:According to the latest UNICEF report, Polish children put on weight at the highest pacein Europe. The number of overweight children has doubled in the last decade. The aim of the work was to assess the effects of kinesiotherapy implemented during a 3-week rehabilitationcamp on changes in motor skills parameters measured on the Leonardo dynamometric platform (Novotec Medical) and on body mass in patients with simple obesity. Materialand methods:The study group included 32 children and youth aged 7-16 with simple obesity who underwent an exercise programme during a 3-week rehabilitation camp. The subjects were examined twice, i.e. at the beginning and at the end of the camp. The control group consisted of 70 healthy children within the same age range who were examined once. Body mass and body height were measured and the BMI was calculated (taking into account centile charts) for all the study participants. Motor skills were assessed on the basis of avertical jump performed on the Leonardo GRFP (GroundReaction Force Platform). The following data were registered: jump velocity, maximum jump height, strength, power, power with reference to body mass and the Esslinger Fitness Index (EFI). Daily kinesiotherapy included exercises in the form of circuit training and water exercises. All the patients participated in meetings with a dietician and a clinical psychologist. Results:Statistically significant reduction in body mass after a 3-week rehabilitation camp was noted in 27 patients with simple obesity (84.1%) (p<0.05). Motor parameters did not improve significantly. Conclusions:Regular physical activity resulted in weight loss only. However, physical activity did not bring about positive changes in motor parameters.

Modelling and analysis of the vehicle underbody and the occupants subjected to a shallow-buried-mine blast impulse

When a charge is ignited at the bottom of a vehicle, the underbody and the occupants are the most vulnerable. The protection of the vehicle underbody is still a significant problem in the environment of a buried-mine blast impulse. The first part of this study presents an algorithm that can be used to simulate a shallow-buried-mine blast. Models using the multiple-material arbitrary Lagrangian–Eulerian algorithm and the initial-impulse mine algorithm respectively were constructed on the basis of experiments carried out by Anderson et al. The accuracy and superiority of the initial-impulse mine algorithm were proved by comparing the results for the jump velocity and the computation time. The second part introduces a blast experiment on a full-scale armoured vehicle. The occupant was represented by a Hybrid III 50th-percentile adult-male dummy. A numerical model was established using the initial-impulse mine method; the seat position represented the worst-case situation, which was same as for the experiments. A comparison of the experimental data and the simulation results, which include the peak acceleration of the floor and the force to which the dummy’s tibia is subjected, showed good agreement.

A Randomized, Controlled Trial of Vitamin D Supplementation upon Musculoskeletal Health in Postmenarchal Females

Context: There has been a resurgence of vitamin D deficiency rickets throughout the developed world, with infants and adolescents being primarily affected. Adolescence is a crucial period for muscle and bone mineral accumulation. Objective: The aim was to determine the effect of vitamin D supplementation on the adolescent musculoskeletal system. Design and Setting: We conducted a community-based, double-blind, randomized controlled trial in a secondary school. Participants: Postmenarchal 12- to 14-yr-old females participated in the trial. Ninety-nine were screened, 73 were included in randomized controlled trial, and 69 completed the trial. There were no adverse events. Intervention: Four doses of 150,000 IU vitamin D2 (ergocalciferol) were given over 1 yr. Main Outcome Measures: Dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and jumping mechanography were used. Results: At follow-up, 25-hydroxyvitamin D [25(OH)D] status was 56.0 ± 8.9 nmol/liter in the intervention group and 15.8 ± 6.6 nmol/liter in controls. There were no effects of supplementation on bone; however, for muscle function, efficiency of movement improved in the vitamin D-treated group. There was an interaction between baseline 25(OH)D concentration and response to vitamin D supplementation for muscle jump velocity. Conclusions: Despite improvements in 25(OH)D status, treatment with vitamin D2 was not shown to increase mineral accretion, bone geometry or strength, muscle force, or power. There were greater increases in jump velocity in girls with the lowest baseline 25(OH)D concentrations. Lack of effect of intervention after the period of peak mineral and muscle mass accretion suggests that earlier action is required.

Boundary Conditions for Multi-Component Slip-Flows Based on the Kinetic Theory of Gases

General temperature-jump, velocity-slip, and concentration-jump conditions on solid surfaces in rarefied multi-component gas flows are developed using the kinetic theory of gases. The presented model provides general boundary conditions which can be simplified according to the problem under consideration. In some limiting cases, the results of the current work are compared to the previously available and widely used boundary conditions reported in the literature. The details of the mathematical procedure are also provided to give a better insight about the physical importance of each term in the slip/jump boundary conditions. Also the disagreements between previously reported results are investigated to arrive at the most proper expressions for the slip/jump boundary conditions. The temperature-jump boundary condition is also modified to handle polyatomic gas flows unlike previously reported studies which were mostly concerned with monatomic gases.