排序方式： 共有66条查询结果，搜索用时 78 毫秒
31.
目的以客观测量的体力活动水平为基础,分析不同持续时间活动的频率及其占总活动时间的比例,从而掌握学龄前儿童体力活动簇集特征。方法根据知情、自愿原则,在上海市杨浦和宝山2个区共招募306名学龄前儿童为受试者,通过连续7 d佩戴加速度传感器ActiGraph GT3X+测量其日常体力活动水平,在此基础上将每次体力活动按强度和持续时间进行分类,并统计不同持续时间的活动平均每天出现的频率及其占总累积活动的比例。结果共有146名受试者[男85名,女61名;平均月龄为(57.7±5.0)月]7 d测量数据均有效,被纳入最终统计分析。发现采样间隔为1 s时,学龄前儿童平均每次体力活动持续时间≤4 s,且70%以上的中等强度和大强度体力活动持续时间为2~3 s。结论学龄前儿童体力活动以持续时间较短的零星活动为主。为准确测量学龄前儿童体力活动,特别是中到大强度体力活动水平,宜采用较短的加速度传感器采样间隔(如3 s或更短时间)。 相似文献
32.
目的调查轻度智障儿童基本运动技能(FMS)与体力活动水平,探讨二者之间的关系,为该群体运动参与能力的提升及其健康促进提供指导思路。方法选取上海市65名轻度智障儿童作为调查对象,运用TGMD-2和ActiGraph GT3X+三轴加速度传感器分别对其FMS及体力活动水平进行测量和评价,对相关数据进行统计分析。结果轻度智障儿童FMS平均总得分为(67.82±7.31)分,其中位移技能得分显著高于物理控制技能(P<0.01),男生位移技能得分显著高于女生(P<0.05),但物体控制技能无显著性别差异(P>0.05)。15.6%的轻度智障儿童能满足每天60 min中高强度体力活动(MVPA)推荐量,男生平均每天MVPA时间显著高于女生(P<0.01),周末日体力活动时间显著高于上学日(P<0.01)。总体上轻度智障儿童的低强度体力活动(LPA)、MVPA和总体力活动(TPA)时间与FMS得分均呈正相关(r=0.351~0.547,P<0.05)。FMS得分对轻度智障儿童平均每天MVPA时间、TPA时间具有解释意义(R^2=0.381,P<0.01;R^2=0.409,P<0.01)。位移技能是解释每天MVPA时间的唯一变量(β=0.490,P<0.01)。结论轻度智障儿童的FMS发展与体力活动水平整体呈正相关关系,基于该群体技能发展层面的体力活动促进是该领域相关研究的重要方向。 相似文献
33.
Xu-dong Zheng Zhong-he Jin Yue-lin Wang Wei-jun Lin Xiao-qi Zhou 《浙江大学学报(A卷英文版)》2009,10(10):1413-1420
We present a bulk micromachined in-plane capacitive accelerometer fabricated with an improved process flow, by etching only one-fifth of the wafer thickness at the back of the silicon while forming the bar-structure electrode for the sensing capacitor. The improved flow greatly lowers the footing effect during deep reactive ion etching （DRIE）, and increases the proof mass by 54% compared to the traditional way, resulting in both improved device quality and a higher yield rate. Acceleration in the X direction is sensed capacitively by varying the overlapped area of a differential capacitor pair, which eliminates the nonlinear behavior by fixing the parallel-plate gap. The damping coefficient of the sensing motion is low due to the slide-film damping. A large proof mass is made using DRIE, which also ensures that dimensions of the spring beams in the Y and Z directions can be made large to lower cross axis coupling and increase the pull-in voltage. The theoretical Brownian noise floor is 0.47 μg/Hz^1/2 at room temperature and atmospheric pressure. The tested frequency response of a prototype complies with the low damping design scheme. Output data for input acceleration from -1 g to 1 g are recorded by a digital multimeter and show very good linearity. The tested random bias of the prototype is 130 μg at an averaging time of around 6 s. 相似文献
34.
One of the tests used to evaluate the performance of sports surfaces measures the peak deceleration of a rigid mass during
contact with the surface, after being dropped from a set height. It is widely used and is included in a number of international
standards.
The test was carried out using two drop heights on four different designs of artificial cricket pitch, with a full set of
acceleration data being collected over the duration of impact. These data were then integrated twice with respect to time
to produce velocity and displacement information. Oblique impacts of cricket balls were also carried out and analysed using
a high-speed video system to evaluate the playing performance of each pitch design.
It was found that, although the pitches gave quite different readings of peak deceleration, they produced similar values for
coefficient of restitution and were therefore considered to ‘play’ in a very similar way. This was due to a high peak deceleration
reading being accompanied by a short contact time and low peak deceleration being accompanied by a long contact time, meaning
that the change in momentum was similar in both cases. It was concluded that for accelerometer tests to be useful, all the
acceleration-time data should be analysed, rather than the peak value alone. 相似文献
35.
Pablo A. Domene Hannah J. Moir Elizabeth Pummell Allan Knox Chris Easton 《Journal of sports sciences》2016,34(15):1396-1404
The purpose of this study was to gain a holistic understanding of the efficacy of Zumba® fitness in a community-recruited cohort of overweight and physically inactive women by evaluating (i) its physiological effects on cardiovascular risk factors and inflammatory biomarkers and (ii) its mental health-enhancing effects on factors of health-related quality of life (HRQoL). Participants were randomly assigned to either engagement in one to two 1 h classes of Zumba® fitness weekly (intervention group; n = 10) or maintenance of habitual activity (control group; n = 10). Laboratory assessments were conducted pre- (week 0) and post-intervention (week 8) with anthropometric, physiological, inflammatory and HRQoL data collected. In the intervention group, maximal oxygen uptake significantly increased (P < 0.05; partial η2 = 0.56) by 3.1 mL · kg?1 · min?1, per cent body fat significantly decreased (P < 0.05; partial η2 = 0.42) by –1.2%, and interleukin-6 and white blood cell (WBC) count both significantly decreased (P < 0.01) by –0.4 pg · mL?1 (partial η2 = 0.96) and –2.1 × 109 cells · L?1 (partial η2 = 0.87), respectively. Large magnitude enhancements were observed in the HRQoL factors of physical functioning, general health, energy/fatigue and emotional well-being. When interpreted in a community-based physical activity and psychosocial health promotion context, our data suggest that Zumba® fitness is indeed an efficacious health-enhancing activity for adults. 相似文献
36.
Róisín M. Howard Richard Conway Andrew J. Harrison 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(4):450-461
This paper examines the use of sensor devices in sports biomechanics, focusing on current frequency of use of Electromyography (EMG) device preferences. Researchers in the International Society of Biomechanics in Sports were invited to participate in an online survey. Responses on multiple sensor devices highlighting frequency of use, device features and improvements researchers sought in acquisition and analysis methods were obtained via an online questionnaire. Results of the investigation showed that the force platform is the most frequently used device, with inertial measurement units and EMG devices growing in popularity. Wireless functionality and ease of use for both the participant and the practitioner proved to be important features. The main findings of the survey demonstrated need for a simple, low power, multi-channel device which incorporates the various sensors into one single device. Biomechanists showed they were looking for more availability of wireless sensor devices with acquisition and analysis features. The study found there is a need to develop software analysis tools to accompany the multi-channel device, providing all the basic functions while maintaining compatibility with existing systems. 相似文献
37.
针对采用基于电容传感原理的加速度传感器来实现角度测量时出现的非线性问题,提出数据预处理与广义回归神经网络(Generalized Regression Neural Network, GRNN)相结合的非线性标定技术.结合实验,详细分析该技术的标定过程,并对该技术与单一使用GRNN进行标定的标定结果进行对比.实验结果表明,该技术标定速度快、精度高、鲁棒性强、实时性好,能有效拓展电容式加速度传感器用于角度测量的线性范围,有较高的工程实用价值. 相似文献
38.
Christian A. Clermont Lauren C. Benson Sean T. Osis Dylan Kobsar Reed Ferber 《Journal of sports sciences》2019,37(2):204-211
The purpose of this study was to classify runners in sex-specific groups as either competitive or recreational based on center of mass (CoM) accelerations. Forty-one runners participated in the study (25 male and 16 female), and were labeled as competitive or recreational based on age, sex, and race performance. Three-dimensional acceleration data were collected during a 5-minute treadmill run, and 24 features were extracted. Support vector machine classification models were used to examine the utility of the features in discriminating between competitive and recreational runners within each sex-specific subgroup. Competitive and recreational runners could be classified with 82.63 % and 80.4 % in the male and female models, respectively. Dominant features in both models were related to regularity and variability, with competitive runners exhibiting more consistent running gait patterns, but the specific features were slightly different in each sex-specific model. Therefore, it is important to separate runners into sex-specific competitive and recreational subgroups for future running biomechanical studies. In conclusion, we have demonstrated the ability to analyze running biomechanics in competitive and recreational runners using only CoM acceleration patterns. A runner, clinician, or coach may use this information to monitor how running patterns change as a result of training. 相似文献
39.
Irene Rocamora Javier Fernández-Río Natalia María Arias-Palencia 《Physical Education & Sport Pedagogy》2019,24(1):87-102
Background: Advances in technology have changed children’s lifestyle so much that the majority of them do not meet the recommended 60 min of moderate to vigorous physical activity every day. Compulsory Physical Education has been highlighted as an ideal context to achieve the suggested physical activity (PA) goals, since it could be the only place where some students become truly physically active. In those classes, the teacher selects a pedagogical approach and this selection could be vital to meet the advised PA levels.Purpose: The goal was to assess the effects of two instructional approaches, Sport Education Model (SEM) and Direct Instruction (DI) in Primary Education students’ physical activity intensity levels, game performance, and friendship goals.Method: A total of 88 students with an average age of 11.16?±?0.63 years, enrolled in two year-5 (from 10 to11 years) and two year-6 (from 11 to 12 years) Physical Education classes of the same school agreed to participate. The number of participants in the SEM was 47 and in DI was 41. The schools’ administration distributed one class of each grade to the experimental group, which experienced SEM, and to the non-equivalent group, which experienced DI. The content selected for both study groups was the same: Handball. Both study groups experienced a 15-session learning unit (45 min per class, three sessions per week). The goal was to conduct the experiment in a non-manipulated (intact) educational context. It followed a pre-test, post-test, experimental, non-equivalent group design. Participants wore Actigraph GT3X accelerometers in order to monitor physical activity levels, answered questionnaires to assess friendship goals, and their game performance was assessed using the Game Performance Assessment instrument (GPAI).Results: Results showed that students who experienced the SEM had significantly higher light and moderate physical activity levels, friendship-approach and friendship-avoidance goals, while the ones who experienced DI had significantly higher sedentary physical activity levels. The GPAI scores showed significant gains in students’ game performance in both study groups, but these were larger in the SEM one.Conclusions: The SEM could be considered more effective than DI to improve Primary Education students’ PA levels, game performance and friendship goals. 相似文献
40.