Prediction of maximum oxygen consumption from walking, jogging, or running

The purpose of this study was to develop a submaximal, 1.5-mile endurance test for college-aged students using walking, jogging, or running exercise. College students (N = 101: 52 men, 47 women), ages 18-26years, successfully completed the 1.5-mile test twice, and a maximal graded exercise test. Participants were instructed to achieve a "somewhat hard" exercise intensity (rating of perceived exertion = 13) and maintain a steady pace throughout each 1.5-mile test. Multiple linear regression generated the following prediction equation: VO2 max = 65.404 + 7.707 x gender (1 = male; 0 =female) - 0.159 x body mass (kg) - 0.843 x elapsed exercise time (min; walking, jogging orrunning). This equation shows acceptable validity (R = .86, SEE = 3.37 ml x kg(-1) min(-1)) similar to the accuracy of comparable field tests, and reliability (ICC = .93) is also comparable to similar models. The statistical shrinkage is minimal (R(press) = 0.85, SEE(press) = 3.51 ml x kg(-) x min(-1)); hence, it should provide comparable results when applied to other similar samples. A regression model (R =.90, and SEE = 2.87 ml x kg(-1) min(-1)) including exercise heart rate was also developed: VO2 max = 100.162 +/- 7.301 x gender(1 = male; 0 =female) - 0.164 x body mass (kg) - 1.273 x elapsed exercise time -0.156 x exercise heart rate, for those who have access to electronic heart rate monitors. This submaximal 1.5-mile test accurately predicts maximal oxygen uptake (VO2max) without measuring heart rate and is similar to the 1.5-mile run in that it allowsfor mass testing and requires only a flat, measured distance and a stopwatch. Further, it can accommodate a wide range of fitness levels (from walkers to runners).     

Understanding the role of shaft stiffness in the golf swing

Theoretically, shaft stiffness can alter shot distance by increasing clubhead speed or altering clubhead orientation at impact. A 3D forward dynamics model of a golfer and flexible club simulated the downswing. A genetic algorithm optimized the coordination of the model’s muscles (four torque generators) to maximize clubhead speed. The maximum torque output and maximum rate of torque development from the torque generators were varied to simulate the swing of golfers that generate different clubhead speeds. Four shafts of varying stiffness (flexible, regular, stiff, and completely rigid) were entered into these simulations to examine the role that shaft flexibility had on clubhead speed and orientation at impact. Shaft stiffness was found to have a meaningful effect only on clubhead orientation (dynamic loft and dynamic close) at impact. There was no evidence to support the premise that matching the stiffness properties of the shaft with the golfer would improve clubhead speed.     

Aerobic Capacity in Black Adolescent Girls

Abstract

Our purpose was to determine the aerobic capacities (VO₂max) of a group of black female adolescents (age = 11.4 ? 15.8 years) randomly chosen from a single urban school. Of 91 girls selected, 64 performed an incremental treadmill running test to volitional exhaustion and achieved VO₂max as determined from expired gas measures. Other measures included height (m), weight (kg), and calf and triceps skinfolds (for % fat estimates). Girls were also asked whether they had achieved menarche. VO₂max averaged 37.3 ± 6.2 ml·kg^?1 ·min^?1 and was significantly correlated (r[62]) with height (?.32, p < .01), body mass index (?.63, p < .001), and % fat (?.65, p < .001) but not with age (?.16, p > .10). Postmenarchal girls were significantly taller and older than premenarchal girls. Contrary to previous studies, the girls' VO₂max values were not related to biological age. Our subjects' aerobic capacity values averaged 14% less than those of nonblack U.S. female adolescents previously reported in the literature. This difference in VO₂max was primarily a function of body weight. Study implications support the possibility that overweight in adult black women may originate prior to or during early adolescence. Future longitudinal studies should be designed to investigate the effects of aerobic fitness on cardiovascular risk factor reduction in black adolescent girls.     

Complex innovation policy systems: Towards an evaluation mix

The mix of contemporary innovation policies impacting on a given territory are typically characterised by quite different underlying rationales and instruments. Complexity is further increased by multi-level considerations. Thus policies with different characteristics and from different administrative levels are continually interacting with one another in complex policy systems. These interactions significantly complicate the evaluation of individual policies, and raise a series of difficult questions around how their respective evaluation processes should interact to facilitate learning around the performance of policy systems. This paper contributes with a simplified definition of an innovation policy system as the conjuncture of policy mix and multi-level dimensions, from which a series of steps are proposed for arriving at an evaluation mix relevant for the specific characteristics of a given policy space. These ideas are explored with respect to the case of the Basque Country region of Spain and signal an agenda for further applied policy research.     

How the experience of assessed collaborative writing impacts on undergraduate students’ perceptions of assessed group work

A time-series analysis was used to investigate Arabic undergraduate students’ (n = 50) perceptions of assessed group work in a major government institution of higher education in Qatar. A longitudinal mixed methods approach was employed. Likert scale questionnaires were completed over the duration of a collaborative writing event. Additionally, open-ended questionnaires were administered after the students received their grade for their term paper. This study found that the participants’ perceptions were positive towards assessed group work throughout the duration of the event, changed in a statistically significant way after the submission of the first piece of formally assessed work, and are temporal and liable to change depending on what is experienced. The results of this study suggest that: assessed collaborative writing is a feasible pedagogical tool within higher education; undergraduate learners place value on group work as it enables them to collaboratively generate, share and develop their ideas; and researchers who investigate perceptual or attitudinal changes should consider whether their study requires time-sensitive methodology.     

合作体验学习法

合作体验学习法（Tribes Learning Communities）是北美学校教育改革比较成功的一种尝试,打破传统的教师为中心的课堂管理模式,创造以学生为中心的课堂氛围,将课堂重心从教师教转到学生学。本文介绍几种在这样的教学指导思想下的教学策略框架,供课改中正在探索的老师们借鉴参考。     

Reliability and validity of field-based fitness tests in youth soccer players

This study aimed to establish between-day reliability and validity of commonly used field-based fitness tests in youth soccer players of varied age and playing standards, and to discriminate between players without (“unidentified”) or with (“identified”) a direct route to professional football through their existing club pathway. Three-hundred-and-seventy-three Scottish youth soccer players (U11–U17) from three different playing standards (amateur, development, performance) completed a battery of commonly used generic field-based fitness tests (grip dynamometry, standing broad jump, countermovement vertical jump, 505 (505COD) and T-Drill (T-Test) change of direction and 10/20 m sprint tests) on two separate occasions within 7–14?days. The majority of field-based fitness tests selected within this study proved to be reliable measures of physical performance (ICC?=?0.83–0.97; p?p?2 (7)?=?101.646, p?相似文献