Top-down and bottom-up guidance in comprehension of schematic football diagrams     

Aïmen Khacharem 《Journal of sports sciences》2017,35(12):1204-1210

Comprehension of a narrated diagram entail complex cognitive processing as learner is challenged to extract the orally evoked information. The present experiment examined the effects of 2 different forms of attention guidance – bottom-up and top-down – on comprehension performance, cognitive load investment, and motivation to learn, using a 2 × 2 mixed design with factors “Expertise” (Expert vs. Novice) and “Condition” (no-signal, circle, segment). The results revealed an expertise reversal effect indicating that the incorporation of visual signals in diagram is effective for novice learners but partially reverses and becomes ineffective for more experienced learners (even though they invested less mental effort and reported higher level of motivation in the segmented condition). The findings suggested that the effectiveness of instructional guidance depends heavily on levels of prior knowledge.  相似文献   

认知负荷对乒乓球运动员注意空间的影响*     

杨〓义  岳珍珠 《广州体育学院学报》2019,(2):99-101

目的 同时注意空间中多个目标刺激对于乒乓球运动员非常重要。考察认知负荷对青少年乒乓球运动员注意分布的影响。方法：实验中采用计算机行为实验，控制认知负荷（同时注意的目标数量为2、4或6个），并且在不同注意范围（离中央注视点3°、6°和9°视角）的位置上同时呈现刺激，要求被试对刺激的亮度变化做辨别反应。结果：:认知负荷对于乒乓球运动员的注意范围有显著调节。当刺激个数为2时，在3°和6°视角条件下呈现的刺激反应时均显著快于9°视角条件下的刺激。当刺激个数为4时，视角为3°条件下的反应时快于视角为6°和9°时的反应时，而视角为6°时又比视角为9°时的反应时显著要快。当刺激个数为6时，视角为3°时的反应时均快于视角为6°和9°时的反应时。结论：当前研究证明随着认知负荷增加，乒乓球运动员注意焦点范围显著缩小。可以通过测量运动员在高负荷条件下注意焦点的范围来进行运动员的选拔。  相似文献   

Effects of pairs of problems and examples on task performance and different types of cognitive load     

《Learning and Instruction》2014

In two studies, we investigated whether a recently developed psychometric instrument can differentiate intrinsic, extraneous, and germane cognitive load. Study I revealed a similar three-factor solution for language learning (n = 108) and a statistics lecture (n = 174), and statistics exam scores correlated negatively with the factors assumed to represent intrinsic and extraneous cognitive load during the lecture. In Study II, university freshmen who studied applications of Bayes' theorem in example–example (n = 18) or example–problem (n = 18) condition demonstrated better posttest performance than their peers who studied the applications in problem–example (n = 18) or problem–problem (n = 20) condition, and a slightly modified version of the aforementioned psychometric instrument could help researchers to differentiate intrinsic and extraneous cognitive load. The findings provide support for a recent reconceptualization of germane cognitive load as referring to the actual working memory resources devoted to dealing with intrinsic cognitive load.  相似文献   

我国男子高水平三级跳远运动员专项力量训练安排研究     

袁晓毅  丁振峰  关长亮  郭元奇 《北京体育大学学报》2016,39(1):112-118

摘要：男子三级跳远是我国参加奥运会田径比赛的潜优势项目，专项力量是影响三级跳远比赛成绩和技术水平提升的关键因素，运用文献资料法、专家访谈法、实地调查等研究方法，分析研究我国最优秀的6名男子三级跳远运动员专项力量训练安排。结论：1）我国男子高水平三级跳远运动员的力量训练内容、方法手段、计划与负荷基本符合世界潮流，但训练中缺少单腿支撑进行的蹲、拉、提、举等练习，不够贴近专项需要；2）专项力量训练器材与世界发达国家相比科技化含量不高；3）专项力量负荷调整控制主要依赖教练员经验与身体素质指标推算。  相似文献   

Objective and subjective methods for quantifying training load in wheelchair basketball small-sided games     

Aitor Iturricastillo  Cristina Granados  Asier Los Arcos  Javier Yanci 《Journal of sports sciences》2017,35(8):749-755

The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards’ training load and Stagno’s training impulses (TRIMP_MOD) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards’ training load and TRIMP_MOD), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P < 0.05; effect size (ES) = 0.66, moderate] and fourth bouts (P < 0.05; ES = 0.64, moderate) than in the first bout, but other measures did not differ. Mean correlations indicated a trivial and small relationship among HR-based and RPE-based training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other.  相似文献   

Effects of tapering on physical match activities in professional soccer players     

Mohamed Saifeddin Fessi  Nidhal Zarrouk  Valter Di Salvo  Cristoforo Filetti  Alan R. Barker 《Journal of sports sciences》2016,34(24):2189-2194

ABSTRACT

This study aimed to examine: (i) the effect of decreasing training load (TL) during taper weeks on physical match activities in professional soccer players, and (ii) to disclose the relationship between weekly TL and physical match activities. Rating of perceived exertion was collected after each training session and match to quantify the TL in 19 professional players over 17 standard and 7 taper weeks during the season. Physical match activities were quantified by a computerised match analysis system and compared between standard training and taper weeks. Compared to standard weeks, the duration and frequency of training sessions during the taper weeks decreased (?21.7% and ?18.8%, respectively; P < 0.01) with no change in intensity (?4.8%; P = 0.09). Consequently, the weekly TL decreased during the taper weeks (?25.5%; P < 0.01). Increases in distance covered by intense running (+15.1%; P < 0.05), high-intensity running (HIR) (+15.7%; P < 0.01), number of sprints (+17.8%; P < 0.05) and number of high-speed runs (+15.7%; P < 0.05) were observed during the seven matches played after the taper weeks. High relationships were observed between TL and HIR distance covered, number of HIR and number of sprints (r = ?0.53; r = ?0.55; r = ?0.65, respectively; P < 0.01). Decreasing TL during taper weeks by reducing training duration and frequency but maintaining intensity was associated with an increase in physical activities during matches. However, it needs to be determined whether tapering or other match factors led to the changes in match activity.  相似文献   

Force–velocity property of leg muscles in individuals of different level of physical fitness     

Ivan Cuk  Dragan Mirkov  Aleksandar Nedeljkovic  Milos Kukolj  Dusan Ugarkovic 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(2):207-219

The present study explored the method of testing muscle mechanical properties through the linear force–velocity (F–V) relationships obtained from loaded vertical jumps. Specifically, we hypothesised that the F–V relationship parameters depicting the force, power, and velocity of the tested muscles will differ among individuals of different physical fitness. Strength trained, physically active, and sedentary male participants (N = 10 + 10 + 10; age 20–29 years) were tested on maximum countermovement and squat jumps where manipulation of external loads provided a range of F and V data. The observed F–V relationships of the tested leg muscles were approximately linear and mainly strong (median correlation coefficients ranged from 0.77 to 0.92; all p < 0.05), independently of either the tested group or the jump type. The maximum power revealed higher values in the strength trained than in the physically active and sedentary participants. This difference originated from the differences in F-intercepts, rather than from the V-intercepts. We conclude that the observed parameters could be sensitive enough to detect the differences among both the individuals of different physical fitness and various jump types. The present findings support using loaded vertical jumps and, possibly, other maximum performance multi-joint movements for the assessment of mechanical properties of active muscles.  相似文献   

Determining optimal cadence for an individual road cyclist from field data     

Robert Reed  Simon Adrian Jobson  Louis Passfield 《European Journal of Sport Science》2016,16(8):903-911

The cadence that maximises power output developed at the crank by an individual cyclist is conventionally determined using a laboratory test. The purpose of this study was two-fold: (i) to show that such a cadence, which we call the optimal cadence, can be determined using power output, heart-rate, and cadence measured in the field and (ii) to describe methodology to do so. For an individual cyclist's sessions, power output is related to cadence and the elicited heart-rate using a non-linear regression model. Optimal cadences are found for two riders (83 and 70 revolutions per minute, respectively); these cadences are similar to the riders’ preferred cadences (82–92?rpm and 65–75?rpm). Power output reduces by approximately 6% for cadences 20?rpm above or below optimum. Our methodology can be used by a rider to determine an optimal cadence without laboratory testing intervention: the rider will need to collect power output, heart-rate, and cadence measurements from training and racing sessions over an extended period (>6 months); ride at a range of cadences within those sessions; and calculate his/her optimal cadence using the methodology described or a software tool that implements it.  相似文献   

Effects of load mass carried in a backpack upon respiratory muscle fatigue     

Mark Faghy  Sam Blacker  Peter I. Brown 《European Journal of Sport Science》2016,16(8):1032-1038

Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h^?1 wearing a backpack of either 0 (LC₀), 10 (LC₁₀), 15 (LC₁₅) or 20?kg (LC₂₀). Inspiratory (P_Imax) and expiratory (P_Emax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean P_Imax and P_Emax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.  相似文献   

矿井多风机风压优化计算机调节系统设计     

王国臣  刘宪文 《鸡西大学学报》2001,(3)

经过对多风机通风网络分析,利用现有的VNETPC模拟程序,建立了多风机风压优化计算机调节系统.该系统允许计算机自动调整多风机风压,直到各用风地点获得最佳可接受的风量分配为止.  相似文献