Cross-sectional comparison of body composition and resting metabolic rate in Premier League academy soccer players: Implications for growth and maturation

ABSTRACT

For the first time we aimed to: (1) assess fat-free mass (FFM) and RMR in youth soccer players, (2) compare measured RMR to estimated RMR using previously published prediction equations, and (3) develop a novel population-specific prediction equation. In a cross-sectional design, 99 males from a Premier League academy underwent assessments of body composition (DXA) and RMR (indirect-calorimetry). Measured RMR was compared to estimated values from five prediction equations. A novel RMR prediction equation was developed using stepwise multiple regression. FFM increased (P<0.05) between U12 (31.6±4.2 kg) and U16 (56.3±5.3 kg) after which no further increases occurred (P>0.05). RMR in the U12s (1655±195 kcal.day^?1), U13s (1720±205 kcal.day^?1) and U14s (1846±218kcal.day^?1) was significantly lower than the U15s (1957±128 kcal.day^?1), U16s (2042±155 kcal.day^?1), U18s (1875±180 kcal.day^?1) and U23s (1941±197 kcal.day^?1) squads (P>0.05). FFM was the single best predictor of RMR (r²=0.43; P<0.01) and was subsequently included in the novel prediction equation: RMR (kcal.day^?1) = 1315 + (11.1 x FFM in kg). Both FFM and RMR increase from 12-16 years old, thus highlighting the requirement to adjust daily energy intake to support growth and maturation. The novel prediction RMR equation developed may help to inform daily energy requirements.     

Using Computing Power to Replace Lawyers: Advances in Licensing and Access

Faculty, librarians, students, and administrators are all faced with questions concerning permitted uses of licensed content. Rather than wrangle with the complexities of copyright, many would prefer a simple automated solution. The Stanford Center for Legal Informatics created such a tool through a research project that evolved into SIPX, a commercial copyright service. The Copyright Clearance Center (CCC) created a product concept but faced challenges in converting it into an academic product.     

Lessons from professional identity development literature: A qualitative content analysis

The development of a professional identity as a counselor is the result of training, practice, and integration into a community of professional counselors and is defined as the synthesis of personal and professional behaviors, values, ethics, and worldview. The research on this topic has been plentiful, but this systemic and systematic review of the research literature provides a comprehensive overview of this important concept for counselor training and supervision.     

Interferences from blood collection tube components on clinical chemistry assays

Improper design or use of blood collection devices can adversely affect the accuracy of laboratory test results. Vascular access devices, such as catheters and needles, exert shear forces during blood flow, which creates a predisposition to cell lysis. Components from blood collection tubes, such as stoppers, lubricants, surfactants, and separator gels, can leach into specimens and/or adsorb analytes from a specimen; special tube additives may also alter analyte stability. Because of these interactions with blood specimens, blood collection devices are a potential source of pre-analytical error in laboratory testing. Accurate laboratory testing requires an understanding of the complex interactions between collection devices and blood specimens. Manufacturers, vendors, and clinical laboratorians must consider the pre-analytical challenges in laboratory testing. Although other authors have described the effects of endogenous substances on clinical assay results, the effects/impact of blood collection tube additives and components have not been well systematically described or explained. This review aims to identify and describe blood collection tube additives and their components and the strategies used to minimize their effects on clinical chemistry assays.     

谈中医学对运动性疲劳的认识

如何尽快消除运动性疲劳,从而提高运动竞技能力,是当今世界运动训练科学和运动医学领域中最为重要的和正待解决的问题之一。关于运动性疲劳的研究,由来已久,但因认识和研究的方法不同,研究结果众说纷纭,各具特点。中医学是一门研究人体生理病理、疾病诊断与防治以及摄生康复的传统医学科学,其从整体观念和辨证论治出发,强调以"养"为主,提倡机体的"阴阳平衡",重视脏腑之间的联系,注重身心和谐发展,在运动医学的防治方面发挥了巨大作用,而中医学对运动性疲劳也有其独特的见解,文章将以中医学的视角对运动性疲劳的含义、病因、病机三方面进行论述,以期望能更好地发挥中医学在运动性疲劳的防治中的作用。     

A comparative study of baseball bat performance

The results of a comparative study of five aluminum and one wood baseball bats are presented. The study includes an analysis of field data, high-speed laboratory testing, and modal analysis. It is found that field performance is strongly correlated with the ball–bat coefficient of restitution (BBCOR) and only weakly correlated with other parameters of the bat, suggesting that the BBCOR is the primary feature of a bat that determines its field performance. It is further found that the instantaneous rotation axis of the bat at the moment of impact is very close to the knob of the bat and that the rotational velocity varies inversely with the moment of inertia of the bat about the knob. A swing speed formula is derived from the field data and the limits of its validity are discussed. The field and laboratory measurements of the collision efficiency are generally in good agreement, as expected on theoretical grounds. Finally, the BBCOR is strongly correlated with the frequency of the lowest hoop mode of the hollow bats, as predicted by models of the trampoline effect.