Anthropometric and Performance Parameters of Japanese High School American Football Players: A Case Study of Selection for International Matches

This study aimed to compare the anthropometric and performance parameters between American football players from different high school grades and to compare their physical characteristics to the normative values for U S and Japanese players fromprevious studies The analysis included 240 grade 10 and 11 American football players The testing included height body mass broad jump 40-yard dash and pro-agility shuttle The analysis was stratified by position linemen offensive and defensive big skill players fullbacks tight ends and linebackers and skill players wide receivers running backs and defensive backs The only between-grade difference was body mass for linemen Cohen s d 0 6 with no moderate effects for all other measured variables d 0 6 No Japanese players were better in both mass and performance measures than U S elite high school players The strength and conditioning program for long-term athlete development should be established for American football players in Japa

Annual Changes in the Physical Characteristics of Japanese Division I Collegiate American Football Players

We aimed to examine the annual changes in various physical characteristics of Japanese Division I (D1) Collegiate American footballers according to their positional groups. We measured body mass, and assessed performance in three gym tests (bench press, back squat, and power clean) and three field tests (40-yard dash, pro-agility shuttle, and broad jump) at each pre-season from 2014 to 2016 for players from a Japanese D1 university. Data from 55 players who completed ≥ 50% (three out of six) of the performance measurements in consecutive years were used in this analysis. Performance data across the two positional groups (skill players and linemen) were analyzed using pairwise t-tests to determine annual changes. The skill players’ body mass increased from their freshman to sophomore years (p 0.8), but not from their sophomore to junior or junior to senior years. The skill players’ 40-yard sprint time was shorter between all the annual comparisons (p 0.8). The linemen’s body mass increased from their freshman to sophomore years, and maintained from their sophomore to junior years and junior to senior years. There were significant improvements in strength and power outputs, but limited improvements in the pro-agility run and broad jump among most of the annual class comparisons for each positional group. These results indicate that annual improvements in the physical characteristics occur nonlinearly for Japanese D1 footballers. They will benefit from targeted strength and conditioning programs. However, the improvements of jumping and agility performances may be limited

Training cessation and subsequent retraining of a world-class female Olympic sailor after Tokyo 2020: A case study

Olympic sailing is a complex sport where sailors are required to predict and interpret weather conditions while facing high physical and physiological demands. While it is essential for sailors to develop physical and physiological capabilities toward major competition, monitoring training status following the competition is equally important to minimize the magnitude of detraining and facilitate retraining. Despite its long history in the modern Olympics, reports on world-class sailors' training status and performance characteristics across different periodization phases are currently lacking. This case study aimed to determine the influence of training cessation and subsequent retraining on performance parameters in a world-class female sailor. A 31-year old female sailor, seventh in the Women's Sailing 470 medal race in Tokyo 2020, completely stopped training for 4 weeks following the Olympics, and resumed low-intensity training for 3 weeks. Over these 7 weeks, 12.7 and 5.3% reductions were observed in 6 s peak cycling power output and jump height, respectively, with a 4.7% decrease in maximal aerobic power output. Seven weeks of training cessation-retraining period induced clear reductions in explosive power production capacities but less prominent decreases in aerobic capacity. The current findings are likely attributed to the sailor's training characteristics during the retraining period.This study was part of Functional Development Project for Resilient Athlete Support commissioned by Japan Sports Agency

A New Evaluation Method of Contact Area at Interface Between Pulsed Surface Discharge and Water

The authors propose a new method for evaluating the contact area of a surface discharge on water by analyzing the resistance of water solution. This method supplements optical observations of light emissions and the Schlieren method. The contact area was modeled as a disk electrode, and the theoretical resistance of water was calculated under the assumption of a mutual similarity between the current and electrostatic fields. A simulated electrostatic field was calculated using a common charge-simulation method. The experimental values of the resistance of water were obtained by dividing the measured voltage drop at water by the measured current. The contact area evaluation was performed by comparing the experimental and theoretical resistance values. The contact area increases with increasing the applied voltage and is practically independent of water depth

Spintum walks-1 quan

We study the quantum walks of two interacting spin-1 bosons. We derive an exact solution for the time-dependent wave function, which describes the two-particle dynamics governed by the one-dimensional spin-1 Bose-Hubbard model. We show that propagation dynamics in real space and mixing dynamics in spin space are correlated via the spin-dependent interaction in this system. The spin-mixing dynamics has two characteristic frequencies in the limit of large spin-dependent interactions. One of the characteristic frequencies is determined by the energy difference between two bound states, and the other frequency relates to the cotunneling process of a pair of spin-1 bosons. Furthermore, we numerically analyze the growth of the spin correlations in quantum walks. We find that long-range spin correlations emerge showing a clear dependence on the sign of the spin-dependent interaction and the initial state

Single Molecular Adsorption of Terbium(III) Bis-phthalocyaninato (TbPc2) Governed by Two Surface Reconstructions of Perovskite Type SrVO3 Epitaxial Ultrathin Film

Using low temperature scanning tunneling microscopy (STM), we observed a single molecule magnet, Tb3+ double decker molecule TbPc2 (Pc = phthalocyaninato), adsorbed on a perovskite type transition metal oxide SrVO3 ultrathin film. TbPc2 molecules adsorbed intact and flat on two surface reconstructions of SrVO3, (2–√×2–√)-R45° and (5–√×5–√)-R26.6°, with different configurations. High resolution STM images revealed that the adsorption configurations were governed by the adatom structure of each surface reconstruction according to the proposed adsorption configurations