Upper and lower thresholds of fat-free mass index in a large cohort of female collegiate athletes

ABSTRACT

Fat-free mass index (FFMI) is a height-adjusted metric of fat-free mass which has been suggested as a useful method of body composition assessment in athletic populations. The purpose of this study was to determine sport-specific FFMI values and the natural upper threshold of FFMI in female athletes. 372 female collegiate athletes (Mean±SD; 20.03±1.55 years, 167.55±7.50 cm, 69.46±13.04 kg, 24.18±5.48% bodyfat) underwent body composition assessment via dual-energy x-ray absorptiometry. FFMI was adjusted to height via linear regression and sport-specific reference values were determined. Between-sport differences were identified using one-way ANOVA with Tukey post-hoc tests. Average FFMI was 18.82±2.08 kg/m²; height-adjusted values were not significantly different (p<0.05) than unadjusted values. FFMI in rugby athletes (20.09±2.23 kg/m²) was found to be significantly higher (p<0.05) than in gymnastics (18.62±1.12 kg/m²), ice hockey (17.96±1.04 kg/m²), lacrosse (18.58±1.84 kg/m²), swim & dive (18.16±1.67 kg/m²), and volleyball (18.04±1.13 kg/m²). FFMI in cross country (16.56±1.14 kg/m²) and synchronized swimming (17.27±1.47 kg/m²) was significantly lower (p<0.05) than in Olympic weightlifting (19.69±1.98 kg/m²), wrestling (19.15±2.47 kg/m²), and rugby. The upper threshold for FFMI in female athletes (97.5^th percentile) was 23.90 kg/m². These results can be used to guide personnel decisions and assist with long-term body composition, training, and nutritional goals.     

Lower extremity injury in female basketball players is related to a large difference in peak eversion torque between barefoot and shod conditions

BackgroundThe majority of injuries reported in female basketball players are ankle sprains and mechanisms leading to injury have been debated. Investigations into muscular imbalances in barefoot versus shod conditions and their relationship with injury severity have not been performed. The purpose of this study was to investigate the effects of wearing athletic shoes on muscular strength and its relationship to lower extremity injuries, specifically female basketball players due to the high incidence of ankle injuries in this population.MethodsDuring pre-season, 11 female collegiate basketball players underwent inversion and eversion muscle strength testing using an isokinetic dynamometer in both a barefoot and shod conditions. The difference between conditions was calculated for inversion and eversion peak torque, time to peak torque as well as eversion-to-inversion peak torque percent strength ratio for both conditions. Lower extremity injuries were documented and ranked in severity. The ranked difference between barefoot and shod conditions for peak torque and time to peak torque as well as percent strength ratio was correlated with injury ranking using a Spearman rho correlation (ρ) with an α level of 0.05.ResultsThe ranked differences in barefoot and shod for peak eversion and inversion torque at 120°/s were correlated with their injury ranking. Ranking of the athletes based on the severity of injuries that were sustained during the season was found to have a strong, positive relationship with the difference in peak eversion torque between barefoot and shod (ρ = 0.78; p = 0.02).ConclusionIt is possible that a large discrepancy between strength in barefoot and shod conditions can predispose an athlete to injury. Narrowing the difference in peak eversion torque between barefoot and shod could decrease propensity to injury. Future work should investigate the effect of restoration of muscular strength during barefoot and shod exercise on injury rates.     

Development of an accelerometer-based multivariate model to predict free-living energy expenditure in a large military cohort

Abstract

This study developed a multivariate model to predict free-living energy expenditure (EE) in independent military cohorts. Two hundred and eighty-eight individuals (20.6 ± 3.9 years, 67.9 ± 12.0 kg, 1.71 ± 0.10 m) from 10 cohorts wore accelerometers during observation periods of 7 or 10 days. Accelerometer counts (PAC) were recorded at 1-minute epochs. Total energy expenditure (TEE) and physical activity energy expenditure (PAEE) were derived using the doubly labelled water technique. Data were reduced to n = 155 based on wear-time. Associations between PAC and EE were assessed using allometric modelling. Models were derived using multiple log-linear regression analysis and gender differences assessed using analysis of covariance. In all models PAC, height and body mass were related to TEE (P < 0.01). For models predicting TEE (r ² = 0.65, SE = 462 kcal · d^?1 (13.0%)), PAC explained 4% of the variance. For models predicting PAEE (r ² = 0.41, SE = 490 kcal · d^?1 (32.0%)), PAC accounted for 6% of the variance. Accelerometry increases the accuracy of EE estimation in military populations. However, the unique nature of military life means accurate prediction of individual free-living EE is highly dependent on anthropometric measurements.     

An external focus of attention is a conditio sine qua non for athletes: a response to Carson,Collins, and Toner (2015)

In this invited response to a Letter to the Editor by Carson, Collins, and Toner (2015), I comment on various issues raised by the authors. I highlight the broad range of tasks and dependent measures used in studies comparing the effectiveness of external versus internal foci of attention. These studies – many of which involved sport skills – have consistently found performance or learning benefits when an external focus was adopted. There is no convincing evidence that performers’ preferences, or their familiarity with a certain focus, have a moderating effect. Anecdotal evidence reported by coaches who have compared the two types of foci is consistent with research findings. An external focus presumably promotes functional connectivity and contributes to goal-action coupling.     

当代缂丝艺术管窥

缂丝,亦称＂刻丝＂,文人称誉是＂雕刻了的丝绸＂。缂丝制品正反两面图案如一,与苏绣双面绣有异曲同工之妙。同时由于经得起摸、擦、揉、搓、洗,它又是千年不坏的艺术织品。它是我国特有的一种丝织手工艺。织时先架好经线,按照底稿在上面描出图画或文字的轮廓,然后对照底稿的色彩,     

"位置平衡"是中国男篮发展中亟待解决的问题

对2009年亚锦赛和东亚运动会中国男篮在关键比赛场次的核心技术指标进行比较分析,揭示占有身高优势和内线实力的中国男子篮球队在这些年的国际大赛中总是不能取得令人满意的竞赛成绩的深层原因;提出在篮球运动赛场上,追求各个"位置"技、战术能力的平衡发展,形成内外结合的团队优势,是中国男篮发展过程中应该着重解决的根本问题.     

A Cross-Sectional Study of Fitness Levels in a Movement Education Program (Bischoff & Lewis, 1987)

Abstract

The net speed of arm movement made in response to sounds of 45, 65 and 85 db. loudness was measured by chronoscope. Reaction time was excluded. Thirty-six college men were tested. In another experiment, the force of successive contractions of the forearm muscles in response to serial auditory stimuli spaced 5 sec. apart was measured by a recording dynamometer. In both experiments there was a balanced order of presenting the three stimulus intensities. In general, the louder sounds produced faster arm movements and stronger contractions of the muscles. In explanation, it is postulated that greater perceived stimulus intensity results in stronger excitation of the pyramidal tracts and consequently more forceful muscular contractions.     

Relationships between physical education (PE) teaching and student self-efficacy,aptitude to participate in PE and functional skills: with a special focus on students with disabilities

Background: Students with disability show an increasing incidence of school failure. Quality teaching and appropriate support may foster high self-efficacy, a predictive factor for successful school outcomes. Physical Education (PE) can provide students with a context in which self-efficacy and participation are promoted leading to improved academic achievement. The transition into secondary school can be challenging for many students with increased educational demands, developmental changes and individual social identification coinciding. A disability may add to the challenge of success.

Methods: Three groups of students, aged 13 years and enrolled in Swedish mainstream schools were targeted (n?=?439). Groups included students with 1. A diagnosed disability, 2. Low grades in PE (D–F) and 3. High grades (A–C) in PE. Questionnaires were collected and analyzed from 30/439 students with a diagnosed disability (physical, neuro-developmental and intellectual) from 26 classes, their classmates and their PE-teachers (n?=?25). Relationships between student self-reports and PE-teachers’ self-ratings were investigated. Also examined was the potential to which students’ functional skills could predict elevated general school self-efficacy, PE specific self-efficacy and aptitude to participate in PE. Results were compared with the total sample and between the three target groups (n?=?121).

Results: For students with disabilities, better self-rated teaching skills were related to lower student perceived general school self-efficacy, PE specific self-efficacy and aptitude to participate in PE. The impact of classroom climate in PE was more obvious among students with disabilities. Perceived functional skills were associated with elevated general school self-efficacy, PE specific self-efficacy and aptitude to participate in PE. Better socio-cognitive functional skills had an overall positive effect on all outcomes. Students with disabilities reported results similar to the total sample, the D–F group scored lower and the A–C group higher than the total sample and the disability group. Elevated self-efficacy in PE is six times less probable in students with disabilities, compared to the A–C group.

Conclusions: Our findings that better teacher planning and grading skills, are detrimental to students disadvantaged by disability is contradictive. Improving the establishment and communication of adapted learning standards at the transition to secondary school is a crucial and a predictive factor for promoting positive school experiences for students with disability. Students with disabilities need to be assured that the intended learning outcomes can be reached by doing activities differently than their typically functioning peers. Consideration of class composition is suggested as a means of promoting a positive learning climate, which would particularly benefit students with disabilities. Allocation of resources to support student socio-cognitive skills would improve experiences for the D–F group and likely promote a positive learning environment.     

徐州市区与周边乡镇语言现状的对比考察(词汇部分)--徐州方言向普通话靠拢趋势考察之五

文章通过环廓市区的铜山县七个乡镇与徐州市区词汇现状的考察，从城乡和新老对比的角度，探讨城乡方言在词汇方面的联系与影响、共性与个性，分析城乡方言的变化趋势度其在变化过程中所存在的客观规律与特点。     

Response to McAvoy and Tudor-Locke on their commentary on our manuscript: "Association of accelerometer-derived step volume and intensity with hospitalizations and mortality in older adults:A prospective cohort study"

<正>Dear Editor,We have read with interest the commentary by McAvoy and Tudor-Locke¹ on our article entitled "Association of accelerometer-derived step volume and intensity with ho spitalizations and mortality in older adults:A prospective cohort study".² The authors expressed some concerns about our methodology used to define accelerometer-derived step intensity and the analytical approach applied in our study.     

Effect of ski boot rear stiffness (SBRS) on maximal ACL force during injury prone landing movements in alpine ski racing: A study with a musculoskeletal simulation model

A common anterior cruciate ligament (ACL) injury situation in alpine ski racing is landing back-weighted after a jump. Simulated back-weighted landing situations showed higher ACL-injury risk for increasing ski boot rear stiffness (SBRS) without considering muscles. It is well known that muscle forces affect ACL tensile forces during landing. The purpose of this study is to investigate the effect of different SBRS on the maximal ACL tensile forces during injury prone landings considering muscle forces by a two-dimensional musculoskeletal simulation model. Injury prone situations for ACL-injuries were generated by the musculoskeletal simulation model using measured kinematics of a non-injury situation and the method of Monte Carlo simulation. Subsequently, the SBRS was varied for injury prone landings. The maximal ACL tensile forces and contributing factors to the ACL forces were compared for the different SBRS. In the injury prone landings the maximal ACL tensile forces increased with increasing SBRS. It was found that the higher maximal ACL force was caused by higher forces acting on the tibia by the boot and by higher quadriceps muscle forces both due to the higher SBRS. Practical experience suggested that the reduction of SBRS is not accepted by ski racers due to performance reasons. Thus, preventive measures may concentrate on the reduction of the quadriceps muscle force during impact.     

Substitution of sedentary time with light physical activity is related to increased bone density in U.S. women over 50 years old. An iso-temporal substitution analysis based on the National health and Nutrition Examination Survey

Abstract

U.S. women are ageing. This is causing rises in osteoporosis prevalence and risk of fracture with related increases in health care costs. Replacing sedentary time with light physical activity may represent a cost effective public health solution to osteoporosis in elderly women. The National Health and Nutrition Examination Survey conducted over the period 2003–2006 provided cross-sectional data on bone mineral density and objectively assessed physical activity among 1,052 women aged 50–85 years old. Substitution analysis was applied to estimate increased bone mineral density and reduced osteoporosis for those women replacing 30?min of sedentary time with an equivalent amount of light physical activity. Substitution of 30?min of sedentary time with an equal amount of light physical activity was associated with increased bone mineral density of about 3?mg/cm2 and a 12% reduced risk of osteoporosis in the spine. When considering overweight women and women over 65 years of age, this association was reinforced and it extended to the pelvis, legs and trunk, resulting in a consistent bone mineral density increase of about 3–6?mg/cm2. The substitution of 30?min of sedentary time with an equal amount of light physical activity appears a possible primary prevention method to reduce osteoporosis and related increases in risk of fracture, mortality, and health care costs in women over 50 years old.     

福建师范大学 bridge 助残志愿服务队管理现状和对策初探

为使助残志愿组织更好的运作,有效的弥补国家政策所顾忌不到的地方,以福建师范大学bridge助残志愿服务队为调查对象,运用文献资料调研法、调查法以及数据统计法对bridge助残志愿服务队的志愿组织管理现状进行剖析,发现助残志愿服务队的组织管理存在管理架构、管理宗旨、管理资源及管理手段的不足。提出组织结构建设方案、相关骨干志愿者的培养与选拔策略及建立一套客观、多维度的评价体系等对策来完善和推进整个服务队的发展。     

单杠直体“京格尔”空翻转体540°成悬垂技术的生物力学分析

本文对单杠高难飞行动作——直体“京格尔”空翻转体540°成悬垂技术,从盖浪、前摆振浪、撒手、空中翻转、再握等五个环节,进行生物力学分析。     

Student outcomes of the physical education and physical literacy (PEPL) approach: a pragmatic cluster randomised controlled trial of a multicomponent intervention to improve physical literacy in primary schools

ABSTRACT

Background: Health organisations such as the United Nations continue to place an expectation on school physical education (PE) programmes and wider school strategies to ensure students develop physical literacy and receive the well-established benefits of meeting physical activity guidelines. Barriers to meet this expectation such as lack of trained PE teachers, lack of time and greater emphasis on academic achievement are ongoing challenges to schools. The purpose of this study was to evaluate the impact of the multi-component Physical Education Physical Literacy (PEPL) intervention, designed to improve students’ fundamental movement skill, perceived physical abilities and level of physical activity.

Method: A qualified PE teacher implemented the PEPL intervention across seven schools, and another seven schools formed a control group as part of a randomised cluster-based trial. Grade 5 students (N?=?318, age 10.4 years?±?SD 0.4) completed assessments of physical activity, fundamental movement skill, attitudes towards PE, and self-perceptions of physical abilities before and after a 33-week intervention. Intervention effects were examined using general linear mixed models. Post-intervention focus groups with students were used to develop insights into experiences and outcomes.

Results: With no significant gender interactions, the PEPL approach led to enhanced object control skills (β?=?1.62; SE?=?0.61; p?=?0.008), with little evidence of any other fundamental movement skill improvements in excess of those in the control group. There was also modest evidence for an effect on accelerometer measured moderate-to-vigorous physical activity (MVPA) during school time (β?=?4.50; SE?=?2.39; p?=?0.058), but this was not accompanied by any significant intervention effect over the entire week. Questionnaires indicated students in the PEPL programme became less satisfied with their own sporting ability (β?=??0.20; SE?=?0.08; p?=?0.013) but qualitative data analyses suggested that they enjoyed the PEPL approach experience, becoming more motivated and confident in their physical abilities.

Conclusions: Evidence of enhanced object control skill, increased confidence and motivation to be physically active, and moderate evidence of more MVPA during school time, indicate that the introduction of the PEPL approach contributed to the development of student physical literacy. A decrease in perceived sporting competence warrants greater attention on student’s self-perceptions in future iterations of the intervention.

Trial registration: Australian New Zealand Clinical Trials Registry identifier: ACTRN12615000066583.