The influence of exercise-induced fatigue on cognitive function

Abstract

Although anecdotal reports suggest that information processing and decision making is impaired immediately following prolonged periods of physical activity, results obtained from laboratory studies of exercise-induced fatigue have been inconsistent. Fatigue effects may be task specific and related to the time of post-exercise testing. The present study examined the effects on adults' performance of two cognitive tasks that differed in processing demands over an 80-min period of fatigue. Thirty young adult men and women were randomly assigned to either an exercise group and completed a 60-min bout of cycle ergometry at 90% ventilatory threshold or a control group and rested for 60 min. Following interventions, each participant completed a simple and complex version of a visual perceptual discrimination test, a 40-min memory-based vigilance test and a repetition of the visual perceptual discrimination tests. Those who exercised evidenced significant decrements in performance on complex perceptual-discrimination tasks compared to participants who rested. The response time of exercisers during a memory-demanding vigilance test were significantly slower than those of participants who rested; however, detection performance did not differ between groups neither was there a decrease in target detection across the vigil. The effects of exercise-induced fatigue may be task specific, with greater effects on perceptual tasks, which involve relatively automatic processing, compared to effortful memory-based tasks.     

On the role of imagery modalities on motor learning

Abstract

In the present study, we examine specifically how the sensory conditions available during physical practice of a task might influence the subsequent use of motor imagery. First, as a pre-test, participants had to physically reproduce knee joint positions with or without vision. Second, they practised motor imagery (15 and 150 trials) with visual, kinaesthetic or visuo-kinaesthetic imagery. A control group with no imagery was included. Post-tests were then performed 10 min and 24 h after each imagery session in a sensory condition similar to that used in the pre-test. Results showed that efficient motor imagery instructions have to take account of the sensory information available during physical experience of the task: kinaesthetic or visuo-kinaesthetic imagery in a no-vision condition, and visual imagery or, to a lesser extent, visuo-kinaesthetic imagery in a vision condition. Discussion focuses on the role of sensory motor memory on motor prediction to simulate a specific movement, and on the similarities between physical and mental practice in the development of sensory-specific movement representation.     

Mental fatigue impairs soccer-specific decision-making skill

ABSTRACT

This study aimed to investigate the impact of mental fatigue on soccer-specific decision-making. Twelve well-trained male soccer players performed a soccer-specific decision-making task on two occasions, separated by at least 72 h. The decision-making task was preceded in a randomised order by 30 min of the Stroop task (mental fatigue) or 30 min of reading from magazines (control). Subjective ratings of mental fatigue were measured before and after treatment, and mental effort (referring to treatment) and motivation (referring to the decision-making task) were measured after treatment. Performance on the soccer-specific decision-making task was assessed using response accuracy and time. Visual search behaviour was also assessed throughout the decision-making task. Subjective ratings of mental fatigue and effort were almost certainly higher following the Stroop task compared to the magazines. Motivation for the upcoming decision-making task was possibly higher following the Stroop task. Decision-making accuracy was very likely lower and response time likely higher in the mental fatigue condition. Mental fatigue had unclear effects on most visual search behaviour variables. The results suggest that mental fatigue impairs accuracy and speed of soccer-specific decision-making. These impairments are not likely related to changes in visual search behaviour.     

Coding of Learned Kinesthetic Location Information

Abstract

The purpose of this study was to determine the coding characteristics of kinesthetic location information acquired during learning trials. Forty-eight blindfolded subjects learned to make a linear response with the right hand to a criterion location during 13 trials. Upon completion of the learning trials, subjects performed 10 trials without knowledge of results (KR) under one of four treatment conditions which were defined by the limb used and the dominant source of feedback available. Specifically, the conditions were right-hand control with kinesthetic feedback, left-hand kinesthetic, right-hand visual, and left-hand visual. The results of the ANOVAs for absolute error (AE) and constant error (CE) from the no-KR trials revealed that the visual feedback groups made significantly greater response errors than did the kinesthetic feedback groups. The blocks main effect for CE was also significant. Analysis of variable error (VE) indicated that the visual feedback groups were significantly more consistent in their responses than were the kinesthetic feedback groups. Within a motor learning paradigm, the concept of a spatial-location coordinate system was supported by the similar performances of the right-handed and left-handed groups. A discrepancy in this system was identified when visual feedback was provided for controlling the response to a location previously learned with kinesthetic cues.     

任务复杂程度对反馈频率适宜值的影响研究

采用单维简单和两维复杂电脑追踪任务,探讨任务复杂程度对反馈频率适宜值的影响.96名右利手的在校大学生随机分为简单任务和复杂任务组(每组男、女各24名).两组受试者分别在25%相对频率(提供反馈的练习次数占总练习次数的25%,简称反馈频率,下同)、50%反馈频率、75%反馈频率、100%反馈频率条件下,连续两天练习简单或复杂任务,每天练习36次.第2天练习结束后休息10min,2组受试者进行无反馈保持测试.一天后,再进行无反馈的保持测试.结果显示:(1)练习阶段,两组受试者的操作绩效随反馈频率增加呈提高趋势;(2)50%反馈频率利于简单任务的技能学习,75%反馈频率利于复杂任务的技能学习;(3)任务复杂程度与反馈频率适宜值存在交互作用,与简单任务相比,操作复杂任务时,应增加反馈的频率.以上结果提示:当信息加工负荷较小(如操作任务较简单)时,减少反馈频率利于技能学习;而当信息加工负荷较大(操作任务较复杂)时,频繁反馈利于技能学习.     

Attentional capture by spoken language: effects on netballers’ visual task performance

Abstract

In two experiments, participants performed visual detection, visual discrimination and decision-making tasks, in which a binary (left/right) response was required. In all experimental conditions, a spoken word (“left”/“right”) was presented monaurally (left or right ear) at the onset of the visual stimulus. In Experiment 1, 26 non-athletes located a target amongst an array of distractors as quickly as possible, in both the presence and absence of spoken cues. Participants performed superiorly in the presence of valid cues, relative to invalid-cue and control conditions. In Experiment 2, 42 skilled netballers completed three tasks, in randomised order: a visual detection task, a visual discrimination task and a netball decision-making task – all in the presence of spoken cues. Our data showed that spoken auditory cues affected not only target detection, but also performance on more complex decision-making tasks: cues that were either spatially or semantically invalid slowed target detection time; spatially invalid cues impaired discrimination task accuracy; and cues that were either spatially or semantically valid improved accuracy and speeded decision-making time in the netball task. When studying visual perception and attention in sport, the impact of concomitant auditory information should be taken into account in order to achieve a more representative task design.     

Editorial Policies

Abstract

A screening test for lateral dominance was administered to 167 college women. Twenty-six showed left dominance. Of this group four were taught to bowl left-handed, six were eliminated from the study for various reasons and 16 were taught to use their preferred hand, the right. All 20 subjects preferred using their right hand. Both groups were equated as to the amount of practice and motor ability. The group using the presumably dominant left hand were significantly poorer in their bowling average than the group which, though demonstrating left dominance, were permitted to bowl with their preferred hand.     

Knee extension fatigue attenuates repeated force production of the elbow flexors

Abstract

Non-local muscle fatigue has been demonstrated with unilateral activities, where fatiguing one limb alters opposite limb forces. Fewer studies have examined if non-local fatigue occurs with unrelated muscles. The purpose of this study was to investigate if knee extensors fatigue alters elbow flexors force and electromyography (EMG) activity. Eighteen males completed a control and fatiguing session (randomised). Blood lactate was initially sampled followed by three maximal voluntary contractions (MVC) with the elbow flexors and two with the knee extensors. Thereafter, subjects either sat (control) or performed five sets of bilateral dynamic knee extensions to exhaustion using a load equal to the dominant limb MVC (1-min rest between sets). Immediately afterwards, subjects were assessed for blood lactate and unilateral knee extensors MVC, and after 1 min performed a single unilateral elbow flexor MVC. Two minutes later, subjects performed 12 unilateral elbow flexor MVCs (5 s contraction/10 s rest) followed by a third blood lactate test. Compared to control, knee extensor force dropped by 35% (p < 0.001; ES = 1.6) and blood lactate increased by 18% (p < 0.001; ES = 2.8). Elbow flexor forces were lower after the fatiguing protocol only during the last five MVCs (p < 0.05; ES = ～0.58; ～5%). No changes occurred between conditions in EMG. Elbow flexor forces significantly decreased after knee extensors fatigue. The effect was revealed during the later stages of the repeated MVCs protocol, demonstrating that non-local fatigue may have a stronger effect on repeated rather than on single attempts of maximal force production.     

Physical Fatigue and Motor Learning

Abstract

In an attempt to investigate the effects of physical fatigue upon the learning of a motor skill, 75 college women were assigned in systematic rotation to either a control group or to one of two experimental groups (N = 25 in each group). All subjects were given a total of 50 trials on the pursuit rotor: 25 trials on Day 1, the practice session; and 25 trials on Day 2, the test session. One of the experimental groups was fatigued early in the practice session while the other was fatigued late in the practice session. Fatigue interpolated early and late was detrimental to subsequent performance improvements but had no effect upon the amount learned.     

Notes: Evaluation of Physical Education in North Carolina High Schools

Abstract

The purpose of this study was to determine if there were differences in learning to perform a novel motor task between two equated groups: one group was subjected to learning the task immediately following a heavy physical work bout on a bicycle ergometer; the other group was subjected to learning the task with no imposed physical exercise. It was found that the subjects who practiced the stabilometer exercise in a fatigued state performed significantly better than subjects in the control group except for test 4. The experimental group also performed significantly better than the control group during the 5th test which was performed without any fatiguing task. It appears from this study that the fatigue state of the learner had a favorable influence on both performance and learning of certain novel motor skills.     

What Undergraduate Physical Education Majors Learn during a Field Experience

Abstract

This study aimed at supporting the specificity of learning hypothesis, when aiming was based on internal cues, as directing the hand toward a “self-defined” target location. Participants practiced modest (20 trials) or intensive (720 trials) training with visual and proprioceptive information or proprioceptive information only. Pretests and posttests were performed in sensory conditions that did or did not match the training condition. Results showed that dynamic visual cues played a dominant role at the beginning of the task, and an intensive practice resulted in increased accuracy of kinesthetic information and efferent mechanisms of motor responses. These results have implications with regard to motor learning conceptions and training as a function of the task constraints.     

身体活动对改善药物成瘾戒断者脑功能损伤的研究——来自抑制加工及脑功能静息态的证据

目的：探讨身体活动对药物成瘾戒断者抑制能力及静息态脑功能的改善,拟为药物成瘾提供有效的辅助治疗手段。方法：将药物成瘾戒断者按身体活动量分为活动组和久坐组,首先进行Go/NoGo抑制能力测试,然后采集他们的静息态功能磁共振数据。选取静息态的两项重要分析方法——低频振幅（amplitude of low frequency fluctuations,ALFF）和局部一致性（regional homogeneity,ReHo）来探讨身体活动对药物成瘾戒断者脑功能损伤的改善。结果：①Go/NoGo测试：活动组NoGo正确率显著高于久坐组。②ALFF分析：活动组在双侧脑岛、左侧额下回眶部、双侧额内侧回、左侧前扣带回、右侧背外侧前额叶、左侧枕上回、左侧辅助运动区、双侧内侧扣带回ALFF显著高于久坐组。③ReHo分析：活动组在左侧枕中回、双侧背外侧前额叶、左侧辅助运动区ReHo显著高于久坐组。这些显著差异脑区主要与成瘾的抑制能力有关。结论：①身体活动能有效地提高药物成瘾戒断者的抑制能力。②身体活动是修复药物成瘾戒断者大脑功能损伤的关键因素之一。身体活动可通过增加药物成瘾戒断者静息状态下脑功能的低频振幅和局部一致性,改善药物成瘾戒断者大脑功能损伤。     

New Frontiers in Visual Search: An Exploratory Study in Live Tennis Situations

This study compares the motor skills and physical fitness of school-age children (6-12 years) with visual impairments (VI; n = 60) and sighted children (n = 60). The relationships between the performance parameters and the children's body composition are investigated as well as the role of the severity of the impairment. The degree of VI did not differentially affect the outcomes. Compared to their sighted peers, the children with VI scored lower on the locomotor and object control skills as assessed with the Test of Gross Motor Development-2, and the physical fitness (Eurofit) parameters of plate tapping, the standing broad jump, the modified 5 × 10-m shuttle run, and 20-m multistage shuttle run (20-MST). Their body mass and body fat indexes were inversely correlated with the standing broad jump and the 20-MST, but positively correlated with handgrip strength. Moreover, significant inverse correlations were found between their locomotor and object control skills on the one hand and plate tapping and the 5 × 10-m shuttle run on the other hand. Given the relatively high proportion (25%) of overweight/obese children within the VI sample, educators are recommended to promote health-related activities and help enhance motor skills in this population.     

An Evaluation of the Instructional Effectiveness of a Computer Lesson in Biomechanics

Abstract

The effects of augmented feedback on perceptions of ability (SPA), practice behaviors, and performance during motor skill instruction of a novel task were investigated. Fourth-grade students (N = 103) were randomly assigned to one of four conditions: (a) no feedback; (b) motivational feedback; (c) task feedback; or (d) motivation and task feedback. They then practiced simple and complex cupstacking skills. On a relatively simple task, the type of feedback did not have a significant effect on children's SPA, practice behaviors, or performance; but on a more complex task, differential effects of feedback were evident. Results indicate that informational feedback is an important factor in facilitating student engagement, fostering positive perceptions of ability, and ultimately improving performance on a challenging task.     

Effects of volleyball match-induced fatigue on knee joint position sense

Abstract

It has been suggested that a greater number of injuries during the last third of practice sessions or matches could be related to alteration of lower limb neuromuscular control due to neuromuscular fatigue. This fatigue-related effect can be mediated by changes in joint proprioception. In athletes, the use of functional fatigue protocols could have the advantage of mimicking the demands of sporting activity, thus reflecting more specifically the changes in neuromuscular control and proprioception observed in sport settings. The purpose of the present study was to assess the effect of fatigue induced by a volleyball match on knee joint position sense in elite volleyball players. Seventeen female volleyball players aged 18.9±4.2 years from the Portuguese national team volunteered for the study. Knee joint position sense was evaluated by an open kinetic chain technique and active knee positioning, and was reported using absolute, relative, and variable angular errors. Joint position sense measures were obtained before and immediately after a simulated volleyball match of five sets. To ensure that the match was sufficiently intense to induce fatigue, the perceived exertion or exercise intensity was assessed at the end of the match using Borg’ s rating of perceived exertion (RPE) scale. All participants completed the volleyball match (90min duration), reaching or exceeding 15 on the RPE scale (15.59±0.71; range 15–17), equivalent to “hard/heavy work”. After the volleyball match, a significant increase in absolute (2.11°) and relative (1.71°) angular errors was detected. Match-induced fatigue significantly exacerbated the overestimation of the test position. Moreover, the reliability and accuracy in estimating knee angles decreased from rest to the fatigued state, as shown by the increase (264%) in variable error. Our results show that fatigue induced by a volleyball match has a marked effect on knee joint position sense in elite female volleyball players. Knee joint position sense was less accurate and less consistent after the volleyball match. Fatigue induced by a simulated competitive volleyball match resulted in proprioceptive deficits, decreasing sensorimotor system acuity in female volleyball players.     

The relationship among motor proficiency, physical fitness, and body composition in children with and without visual impairments

This study compares the motor skills and physical fitness of school-age children (6-12 years) with visual impairments (VI; n = 60) and sighted children (n = 60). The relationships between the performance parameters and the children's body composition are investigated as well as the role of the severity of the impairment. The degree of VI did not differentially affect the outcomes. Compared to their sighted peers, the children with VI scored lower on the locomotor and object control skills as assessed with the Test of Gross Motor Development-2, and the physical fitness (Eurofit) parameters of plate tapping, the standing broad jump, the modified 5 x 10-m shuttle run, and 20-m multistage shuttle run (20-MST). Their body mass and body fat indexes were inversely correlated with the standing broad jump and the 20-MST but positively correlated with handgrip strength. Moreover significant inverse correlations were found between their locomotor and object control skills on the one hand and plate tapping and the 5 x 10-m shuttle run on the other hand. Given the relatively high proportion (25%) of overweight/obese children within the VI sample, educators are recommended to promote health-related activities and help enhance motor skills in this population.     

Stabilometer Performance of Educable Mentally Retarded Children under Differential Feedback Conditions

Abstract

Twelve trials on a stabilometer task were administered to 100 educable mentally retarded children whose IQs ranged from 55 to 80 and whose mean age was 12.6 years. Four groups were trained under different supplementary auditory or visual feedback conditions while a fifth group was trained under control conditions. Using the mean time-in-balance (TIB) as the criterion measure, there were no initial performance differences among groups. Significant TIB performance differences among groups were demonstrated during the supplementary feedback training sessions; the visual/in-balance group demonstrated performance superiority. Final performance measures, obtained after withdrawal from the feedback conditions, were compared among groups; the visual/in-balance group maintained performance superiority over all other study groups. Comparisons within groups, from initial to final performance, indicated that only the control group failed to demonstrate significant performance gains and, therefore, did not acquire the task. The findings showed that only when supplementary auditory and visual feedback training techniques were employed did stabilometer performance improve significantly. The performance superiority of the visual/in-balance condition over all other conditions leads to the conclusion that the supplementary visual feedback technique as a reinforcement to correct responding has the greatest effect on the acquisition of the stabilometer task by educable, mentally retarded children.     

The Veering Tendency of the Arm,When Drawing a Straight Line without Vision

Abstract

Fifty-seven male and female university students were seated individually at a table, blindfolded, and asked to draw a straight line directly away from the center of their bodies. Results indicated that performances with the right hand were, in general, more accurate than those with the left hand. The data also indicated that lines drawn with the right hand veered slightly to the left, while those drawn with the left hand tended to veer to the right. Hand dominance had no effect upon the accuracy of the line-drawing performance.     

Fatigue reduces the complexity of knee extensor torque during fatiguing sustained isometric contractions

Abstract

The temporal structure, or complexity, of muscle torque output reflects the adaptability of motor control to changes in task demands. This complexity is reduced by neuromuscular fatigue during intermittent isometric contractions. We tested the hypothesis that sustained fatiguing isometric contractions would result in a similar loss of complexity. To that end, nine healthy participants performed, on separate days, sustained isometric contractions of the knee extensors at 20% MVC to task failure and at 100% MVC for 60?s. Torque and surface EMG signals were sampled continuously. Complexity and fractal scaling were quantified by calculating approximate entropy (ApEn) and the detrended fluctuation analysis (DFA) α scaling exponent. Global, central and peripheral fatigue were quantified using maximal voluntary contractions (MVCs) with femoral nerve stimulation. Fatigue reduced the complexity of both submaximal (ApEn from 1.02?±?0.06 to 0.41?±?0.04, P?<?0.05) and maximal contractions (ApEn from 0.34?±?0.05 to 0.26?±?0.04, P?<?0.05; DFA α from 1.41?±?0.04 to 1.52?±?0.03, P?<?0.05). The losses of complexity were accompanied by significant global, central and peripheral fatigue (all P?<?0.05). These results demonstrate that a fatigue-induced loss of torque complexity is evident not only during fatiguing intermittent isometric contractions, but also during sustained fatiguing contractions.     

Task complexity and sources of task-related information during the observational learning process

Abstract

Although research has examined the influence of various sources of task information for skill acquisition during observational learning, the results have been ambiguous. The purpose of this study was to examine sources of information in relation to the type of task. One hundred and twenty participants were randomly assigned to one of two sets of six treatment strategies: (1) all model demonstrations; (2) model demonstrations with physical practice with knowledge of performance; (3) model demonstrations with physical practice without knowledge of performance; (4) physical practice without knowledge of performance; (5) physical practice with knowledge of performance; or (6) verbal instructions only. One set learned a simple version of the task while the other set learned a more complex version. Cognitive representation and performance accuracy (spatial and temporal) were assessed. Results indicate that task type does influence the source of information to facilitate skill acquisition. The simple task benefited from model demonstrations, physical practice with knowledge of performance, or a combination of model demonstrations and practice both with and without knowledge of performance, while the complex version benefited more from a combination of model demonstrations and knowledge of performance practice. The results of this study provide an insight into the ambiguity that exists within the observational learning and motor learning literature regarding the effectiveness of information sources for motor skill acquisition.