RUN-UP SPEED PARAMETERS FOR ELEMENTARY SCHOOL LONG JUMPERS

The purposes of this study were to investigate the run-up speed parameters of the elementary long jumpers and to obtain coaching suggestions on the run-up techniques for the coaches. Subjects were nineteen male and female elementary school long jumpers who participated in an athletics competition held in Japan. The run-up speed was collected by using a laser speed apparatus. There was a significant positive relationship between the official jumping distance and the maximum speed. This study revealed that reaching the maximum run-up speed as close to the take-off line as possible would help to maintain the run-up speed and to obtain large the take-off speed and the jumping distance

THREE-DIMENSIONAL ANALYSIS OF THE TAKEOFF MOTION IN THE LONG JUMP

The purposes of this study were to investigate why long jumpers laterally leaned at the touchdown of the takeoff using the three-dimensional kinetics analysis and to obtain suggestions for long jumpers’ training. The subjects were twelve male university long jumpers. Three-dimentional coordinates and ground reaction forces (GRF) were collected by Vicon cameras and a force platform. The results in this study were revealed that the hip joint of the takeoff leg exerted the large abduction torque during the takeoff as well as hip extension torque (peak hip abduction torque, 4.24±3.28 Nm/kg). The hip abductors seemed to help to bear the body against the GRF and to contribute to obtain the vertical CG velocity. These imply why the long jumpers laterally leaned the body at the touchdown of the takeoff

Novel Extrapolation Method in the Monte Carlo Shell Model

We propose an extrapolation method utilizing energy variance in the Monte Carlo shell model in order to estimate the energy eigenvalue and observables accurately. We derive a formula for the energy variance with deformed Slater determinants, which enables us to calculate the energy variance efficiently. The feasibility of the method is demonstrated for the full $pf$-shell calculation of $^{56}$Ni, and the applicability of the method to a system beyond current limit of exact diagonalization is shown for the $pf$+$g_{9/2}$-shell calculation of $^{64}$Ge.Comment: 4 pages, 4figure

Stochastic Estimation of Nuclear Level Density in the Nuclear Shell Model: An Application to Parity-Dependent Level Density in 58^{58}Ni

We introduce a novel method to obtain level densities in large-scale shell-model calculations. Our method is a stochastic estimation of eigenvalue count based on a shifted Krylov-subspace method, which enables us to obtain level densities of huge Hamiltonian matrices. This framework leads to a successful description of both low-lying spectroscopy and the experimentally observed equilibration of $J^\pi=2^+$ and $2^-$ states in $^{58}$Ni in a unified manner.Comment: 13 pages, 4 figure

Angular momentum in skilled kicking pullover performed by elementary school children

Topics in Exercise Science and Kinesiology Volume 3: Issue 1, Article 2, 2022. This study aimed to clarify the differences in body positions and the role of the swing leg, support leg, and head-arm-trunk segment in generating and maintaining angular momentum of the whole body about a horizontal bar as well as how to improve the skill level of successful kicking pullover attempts. Two-dimensional kinematic parameters of successful kicking pullover attempts and body composition indices of 26 fifth-grade elementary school children were collected. Their techniques were classified into excellent and good groups based on the subjective evaluation of three evaluators. Although there were no significant differences in body composition indices between the two groups, the motion phase time during the 4th phase and the total time of the excellent group were significantly shorter compared with the good group. Also, the counterclockwise rotation of the angular momentum of the head-arm-trunk segment and the whole body during the 4th phase was significantly larger in the excellent group than in the good group. These results suggest that maintaining the angular momentum of the head-arm-trunk segment during the 4th phase leads to attempts with shorter time and improves skill levels from the good group to the excellent group. The good group was not able to maintain angular momentum of the whole body during the 4th phase because the peak of the angular momentum of the head-arm-trunk segment and support leg tended to appear earlier than in the excellent group. we newly clarified that teachers need to focus on the body position of the trunk and head during the 4th phase in order for elementary school children to succeed in kicking pullovers more beautifully at a higher level

CONTRIBUTION OF THE JOINT TORQUE OF THE TAKEOFF LEG IN THE LONG JUMP

The purposes of this study were to investigate effects of the joint torques of the takeoff leg on the GRFs in the long jump and to obtain suggestions to long jumpers’ training. The subjects were ten male university long jumpers. Three-dimensional coordinates and ground reaction forces (GRF) were collected by Vicon cameras and a force platform. The force components of the joint torque of the takeoff leg were calculated by a multi-body dynamic method. The results in this study revealed that functions of the hip extensors and abductors seemed to obtain the vertical GRF and to maintain the position of the upper body throughout the takeoff phase. The knee extensors prevented the knee joint from collapsing and bear the body, and the ankle planter flexors played a major important role to generate the vertical GRF