增大跑速对着地时小腿峰值制动的影响

医务工作者常说:快跑有时会增大受伤的可能性。逻辑似乎就是这样:在快跑中骨胳肌的应力随之增大。本实验的目的就是测定跑速增加对每一步肌应力的影响。方法: 十名受过良好训练的短跑运动员在跑台上做下面四种不同跑速的测试:3.35,3.83,4.47,5.36m/s(8,7,6,5分/英里),所有受试者都已熟练掌握了跑台跑技术,并且在采集数据前,受试者先做一些四种跑速的练习。小腿制动的数据采集使用了Kulite微型压阻式加速度计。使用时,用巴沙木包裹后紧紧     

我怎样对小学生们进行劳动教育的

劳动教育总是比较显著的制订在苏联学校教育工作计划中,克服教育脱离生活,培养学生趋向实际活动,这对于小学教师也是同样重要的。     

Evaluation of distance learning delivery of health information management and health informatics programmes: a UK perspective

The aim of the article is to review evaluations of distance learning programmes in health information management, in order to identify the critical success factors for such programmes and discuss future directions. The emphasis is on the UK experience, based partly on reflections on the experience of one programme at University of Wales Aberystwyth (now over 10 years old), and partly on a policy review conducted for the NHS Information Authority and the NHS Information Policy Unit. The methods are, as far as possible, those of a systematic review of existing research, with, additionally, an overview of relevant policy developments for lifelong learning. The topics covered include the aims, objectives and educational philosophies of the programmes. The evidence, combined with the UWA experience, indicates the importance of face-to-face interaction, to complement distance or virtual learning. A student-centred approach to curriculum design and delivery is essential.     

Beta-endorphin infusion during exercise in rats does not alter hepatic or muscle glycogen

The aim of this study was to determine whether beta-endorphin infusion influences liver or muscle glycogen concentration during exercise. Thirty-two rats (Harlan Co., IN, USA) with a body mass of 265-290 g were assigned at random to four groups, each of eight rats: (1) beta-endorphin infusion for 90 min at rest; (2) beta-endorphin infusion for 90 min while running on a rodent treadmill at 22 m x min(-1) and 0% grade; (3) saline infusion (0.9% NaCl) for 90 min at rest; and (4) saline infusion for 90 min while running on a rodent treadmill at 22 m x min(-1) and 0% grade. Beta-endorphin infusion elevated plasma beta-endorphin concentration by 2.5-fold at rest compared with saline infusion at rest, and by two-fold after exercise compared with saline infusion after exercise. Beta-endorphin infusion attenuated exercise-induced glucose concentration but did not alter the fasting hepatic glycogen concentration at rest or after exercise compared with saline infusion. Fasting hepatic glycogen decreased significantly as a result of 90 min of exercise independent of treatment. Deep intermedius muscle glycogen concentration at rest was similar after 90 min of both beta-endorphin and saline infusion and decreased significantly as a result of 90 min of exercise independent of treatment. Our results suggest that liver and muscle glycogenolysis is not responsible for the differences in plasma glucose with beta-endorphin infusion during exercise.     

Knee joint forces during downhill walking with hiking poles

The aim of this study was to determine external and internal loads on the knee joint during downhill walking with and without hiking poles. Kinematic, kinetic and electromyographic data were collected from eight males during downhill walking on a ramp declined at 25 degrees. Planar knee joint moments and forces were calculated using a quasi-static knee model. The results were analysed for an entire pole-cycle as well as differentiated between single and double support phases and between each step of a pole-cycle. Significant differences between downhill walking with and without hiking poles were observed for peak and average magnitudes of ground reaction force, knee joint moment, and tibiofemoral compressive and shear forces (12-25%). Similar reductions were found in patellofemoral compressive force, the quadriceps tendon force and the activity of the vastus lateralis; however, because of a high variability, these differences were not significant. The reductions seen during downhill walking with hiking poles compared with unsupported downhill walking were caused primarily by the forces applied to the hiking poles and by a change in posture to a more forward leaning position of the upper body, with the effect of reducing the knee moment arm.