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Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning.
Wulf, G, Lewthwaite, R
Psychonomic bulletin & review. 2016;(5):1382-1414
Abstract
Effective motor performance is important for surviving and thriving, and skilled movement is critical in many activities. Much theorizing over the past few decades has focused on how certain practice conditions affect the processing of task-related information to affect learning. Yet, existing theoretical perspectives do not accommodate significant recent lines of evidence demonstrating motivational and attentional effects on performance and learning. These include research on (a) conditions that enhance expectancies for future performance, (b) variables that influence learners' autonomy, and (c) an external focus of attention on the intended movement effect. We propose the OPTIMAL (Optimizing Performance through Intrinsic Motivation and Attention for Learning) theory of motor learning. We suggest that motivational and attentional factors contribute to performance and learning by strengthening the coupling of goals to actions. We provide explanations for the performance and learning advantages of these variables on psychological and neuroscientific grounds. We describe a plausible mechanism for expectancy effects rooted in responses of dopamine to the anticipation of positive experience and temporally associated with skill practice. Learner autonomy acts perhaps largely through an enhanced expectancy pathway. Furthermore, we consider the influence of an external focus for the establishment of efficient functional connections across brain networks that subserve skilled movement. We speculate that enhanced expectancies and an external focus propel performers' cognitive and motor systems in productive "forward" directions and prevent "backsliding" into self- and non-task focused states. Expected success presumably breeds further success and helps consolidate memories. We discuss practical implications and future research directions.
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Coordination in Climbing: Effect of Skill, Practice and Constraints Manipulation.
Orth, D, Davids, K, Seifert, L
Sports medicine (Auckland, N.Z.). 2016;(2):255-68
Abstract
BACKGROUND Climbing is a physical activity and sport involving many subdisciplines. Minimization of prolonged pauses, use of a relatively simple path through a route and smooth transitions between movements broadly define skilled coordination in climbing. OBJECTIVES To provide an overview of the constraints on skilled coordination in climbing and to explore future directions in this emerging field. METHODS A systematic literature review was conducted in 2014 and retrieved studies reporting perceptual and movement data during climbing tasks. To be eligible for the qualitative synthesis, studies were required to report perceptual or movement data during climbing tasks graded for difficulty. RESULTS Qualitative synthesis of 42 studies was carried out, showing that skilled coordination in climbing is underpinned by superior perception of climbing opportunities; optimization of spatial-temporal features pertaining to body-to-wall coordination, the climb trajectory and hand-to-hold surface contact; and minimization of exploratory behaviour. Improvements in skilled coordination due to practice are related to task novelty and the difficulty of the climbing route relative to the individual's ability level. CONCLUSION Perceptual and motor adaptations that improve skilled coordination are highly significant for improving the climbing ability level. Elite climbers exhibit advantages in detection and use of climbing opportunities when visually inspecting a route from the ground and when physically moving though a route. However, the need to provide clear guidelines on how to improve climbing skill arises from uncertainties regarding the impacts of different practice interventions on learning and transfer.
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U.S. Army Research on Pharmacological Enhancement of Soldier Performance: Stimulants, Anabolic Hormones, and Blood Doping.
Friedl, KE
Journal of strength and conditioning research. 2015;:S71-6
Abstract
The level playing field of competitive sports is an irrelevant concern in asymmetrical warfare. However, there is a common theme of pressure to use performance-enhancing drugs because athletic or military opponents may be using them to advantage. This interest is fueled by personal anecdotes, misconceptions, and myths, and decisions to use or not to use pharmacological interventions may ignore available scientific data. The U.S. Army has led research in this area, with an abundance of published data extending back to World War II. Behavioral effects have been a consistent concern. A key conclusion to be drawn from this research is that although there may be specialized applications for some of these interventions, the majority of soldiers will gain the greatest performance benefits from effective physical and mental training programs combined with good principles of rest and nutrition. Furthermore, the perceived need to improve human biology with drugs may be solving the wrong problem, trying to fit the human to the demands of poorly conceived tactics, tasks, and equipments instead of capitalizing on human capabilities.
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Iron therapy for improving psychomotor development and cognitive function in children under the age of three with iron deficiency anaemia.
Wang, B, Zhan, S, Gong, T, Lee, L
The Cochrane database of systematic reviews. 2013;(6):CD001444
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Abstract
BACKGROUND Iron deficiency and iron deficiency anaemia (IDA) are common in young children. It has been suggested that the lack of iron may have deleterious effects on children's psychomotor development and cognitive function. To evaluate the benefits of iron therapy on psychomotor development and cognitive function in children with IDA, a Cochrane review was carried out in 2001. This is an update of that review. OBJECTIVES To determine the effects of iron therapy on psychomotor development and cognitive function in iron deficient anaemic children less than three years of age. SEARCH METHODS We searched the following databases in April 2013: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO, LILACS, ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (ICTRP). We also searched the reference lists of review articles and reports, and ran citation searches in the Science Citation Index for relevant studies identified by the primary search. We also contacted key authors. SELECTION CRITERIA Studies were included if children less than three years of age with evidence of IDA were randomly allocated to iron or iron plus vitamin C versus a placebo or vitamin C alone, and assessment of developmental status or cognitive function was carried out using standardised tests by observers blind to treatment allocation. DATA COLLECTION AND ANALYSIS Two review authors independently screened titles and abstracts retrieved from the searches and assessed full-text copies of all potentially relevant studies against the inclusion criteria. The same review authors independently extracted data and assessed the risk of bias of the eligible studies. Data were analysed separately depending on whether assessments were performed within one month of beginning iron therapy or after one month. MAIN RESULTS We identified one eligible study in the update search that had not been included in the original review. In total, we included eight trials.Six trials, including 225 children with IDA, examined the effects of iron therapy on measures of psychomotor development and cognitive function within 30 days of commencement of therapy. We could pool data from five trials. The pooled difference in pre- to post-treatment change in Bayley Scale Psychomotor Development Index (PDI) between iron and placebo groups was -1.25 (95% confidence interval (CI) -4.56 to 2.06, P value = 0.65; I(2) = 33% for heterogeneity, random-effects meta-analysis; low quality evidence) and in Bayley Scale Mental Development Index (MDI) was 1.04 (95% CI -1.30 to 3.39, P value = 0.79; I(2) = 31% for heterogeneity, random-effects meta-analysis; low quality evidence).Two studies, including 160 randomised children with IDA, examined the effects of iron therapy on measures of psychomotor development and cognitive function more than 30 days after commencement of therapy. One of the studies reported the mean number of skills gained after two months of iron therapy using the Denver Developmental Screening Test. The intervention group gained 0.8 (95% CI -0.18 to 1.78, P value = 0.11, moderate quality of evidence) more skills on average than the control group. The other study reported that the difference in pre- to post-treatment change in Bayley Scale PDI between iron-treated and placebo groups after four months was 18.40 (95% CI 10.16 to 26.64, P value < 0.0001; moderate quality evidence) and in Bayley Scale MDI was 18.80 (95% CI 10.17 to 27.43, P value < 0.0001; moderate quality evidence). AUTHORS' CONCLUSIONS There is no convincing evidence that iron treatment of young children with IDA has an effect on psychomotor development or cognitive function within 30 days after commencement of therapy. The effect of longer-term treatment remains unclear. There is an urgent need for further large randomised controlled trials with long-term follow-up.
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Do energy drinks contain active components other than caffeine?
McLellan, TM, Lieberman, HR
Nutrition reviews. 2012;(12):730-44
Abstract
Energy drinks (EDs) contain caffeine and are a new, popular category of beverage. It has been suggested that EDs enhance physical and cognitive performance; however, it is unclear whether the claimed benefits are attributable to components other than caffeine. A typical 235 mL ED provides between 40 and 250 mg of caffeine, equating to doses that improve cognitive and, at the higher levels, physical performance. EDs often contain taurine, guaraná, ginseng, glucuronolactone, B-vitamins, and other compounds. A literature search using PubMed, Psych Info, and Google Scholar identified 32 articles that examined the effects of ED ingredients alone and/or in combination with caffeine on physical or cognitive performance. A systematic evaluation of the evidence-based findings in these articles was then conducted. With the exception of some weak evidence for glucose and guaraná extract, there is an overwhelming lack of evidence to substantiate claims that components of EDs, other than caffeine, contribute to the enhancement of physical or cognitive performance. Additional well-designed, randomized, placebo-controlled studies replicated across laboratories are needed in order to assess claims made for these products.
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Quadrupedal coordination of bipedal gait: implications for movement disorders.
Dietz, V
Journal of neurology. 2011;(8):1406-12
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Abstract
During recent years, evidence has come up that bipedal locomotion is based on a quadrupedal limb coordination. A task-dependent neuronal coupling of upper and lower limbs allows one to involve the arms during gait but to uncouple this connection during voluntarily guided arm/hand movements. Hence, despite the evolution of a strong cortico-spinal control of hand/arm movements in humans, a quadrupedal limb coordination persists during locomotion. This has consequences for the limb coordination in movement disorders such as in Parkinson's disease (PD) and after stroke. In patients suffering PD, the quadrupedal coordination of gait is basically preserved. The activation of upper limb muscles during locomotion is strong, similar as in age-matched healthy subjects although arm swing is reduced. This suggests a contribution of biomechanical constraints to immobility. In post-stroke subjects a close interactions between unaffected and affected sides with an impaired processing of afferent input takes place. An afferent volley applied to a leg nerve of the unaffected leg leads to a normal reflex activation of proximal arm muscles of both sides. In contrast, when the nerve of the affected leg was stimulated, neither on the affected nor in the unaffected arm muscles EMG responses appear. Muscle activation on the affected arm becomes normalized by influences of the unaffected side during locomotion. These observations have consequences for the rehabilitation of patients suffering movement disorders.
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The effectiveness and efficacy of Rhodiola rosea L.: a systematic review of randomized clinical trials.
Hung, SK, Perry, R, Ernst, E
Phytomedicine : international journal of phytotherapy and phytopharmacology. 2011;(4):235-44
Abstract
OBJECTIVE To critically assess the current evidence from randomized clinical trials (RCTs) for or against the effectiveness or efficacy of Rhodiola rosea. DATA SOURCES Systematic literature searches were performed in six electronic databases: AMED (1985-July 2009), CINAHL (1982-July 2009), The Cochrane Library (search in July 2009), EMBASE (1974-July 2009), MEDLINE (1950-July 2009) and Web of Science (searched in July 2009). No language restrictions were imposed. Reference lists of all retrieved articles were searched, and experts and manufacturers were contacted for unpublished RCT. REVIEW METHODS RCTs testing the efficacy or effectiveness of mono-preparations of R. rosea as sole treatment administered orally against a control intervention in any human individual suffering from any condition or healthy human volunteers were included. Studies were selected, data extracted, and quality assessed by two independent reviewers. RESULTS Eleven RCTs met the inclusion criteria; all were placebo-controlled. Six trials investigated the effects of R. rosea on physical performance, four on mental performance, and two in patients diagnosed with mental health condition. The methodological quality of most trials was moderate or good. Only few mild adverse events were reported. CONCLUSION R. rosea may have beneficial effects on physical performance, mental performance, and certain mental health conditions. There is, however, a lack of independent replications of the single different studies. Five of the 10 RCTs reached more than three points on the Jadad score (i.e., good quality). More research seems warranted.
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Binding in voluntary action control.
Nattkemper, D, Ziessler, M, Frensch, PA
Neuroscience and biobehavioral reviews. 2010;(7):1092-101
Abstract
The last decade has seen a proliferation of empirical studies that seek to understand how the cognitive system links voluntary motor actions with their perceptual effects. A view that has found considerable support in this research is the ideomotor approach to action control which holds that actors select, initiate, and execute a movement by activating anticipatory codes of the movement's sensory effects. We, first review the empirical evidence from different paradigms showing that effects of voluntary actions become anticipated during response production. In a second step we survey empirical data investigating the nature of the mechanisms that link voluntary motor actions with their intended and expected perceptual effects. We argue that the integration, or binding, of perceptual and motor codes occurs in action planning where features of intended effects are selectively bound to features of the actions that are selected to achieve these effects in the environment. As a final step we will summarize empirical findings that may elucidate the particular roles of effect-code activation in response production and control.
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Performance alterations associated with occupational exposure to manganese--a meta-analysis.
Meyer-Baron, M, Knapp, G, Schäper, M, van Thriel, C
Neurotoxicology. 2009;(4):487-96
Abstract
The review aimed at quantifying the evidence of performance effects resulting from occupational exposure to manganese. Epidemiological studies published between 1987 and 2008 were analyzed. The approach was based on the meta-analytical method of effect size estimates and sought to contribute to the following issues: (1) identification of the affected functions; (2) identification of sensitive neuropsychological tests; (3) analyses of exposure-effect relationships. Thirteen studies examining 958 exposed and 815 unexposed workers were included in the meta-analysis. Mean concentrations of inhalable manganese ranged from 0.05 to 1.59 mg/m(3), mean concentrations of manganese in whole blood ranged from 8.1 to 48.4 microg/L. Nineteen neuropsychological performance variables were analyzed as they were included in at least three of the identified studies. Apart from two outcomes, the overall effects displayed a negative impact of manganese on performance. Significant overall effects were obtained for six test variables; their size ranged from d=-0.23 to -0.36. Four of the variables measured motor speed and two of them speed of information processing. The analysis of exposure-effect relationships showed that larger effect sizes were more consistently associated with higher concentrations of inhalable manganese than with manganese in blood. The evidence of cognitive and motor performance effects is in accordance with the knowledge about accumulation of manganese in the basal ganglia and the effect of manganese on the neurotransmitter dopamine. Inconsistencies in the relationship between effect sizes and the biomarker manganese in blood were discussed in the context of results indicating that the biomarker might not be sufficiently meaningful for the neurobehavioral alterations. Simple motor performance tests with a distinct speed component seem to be highly recommendable for further studies, because they seem to be appropriate for measuring manganese-related changes, seem to provide homogenous results and their outcomes show consistent relations to exposure. The rigorous quantitative approach was especially appropriate for revealing exposure-effect relationships, but information about individual cumulative exposure would enhance the potential for risk assessment of manganese.
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Neuropsychological speed tests and blood phenylalanine levels in patients with phenylketonuria: a meta-analysis.
Albrecht, J, Garbade, SF, Burgard, P
Neuroscience and biobehavioral reviews. 2009;(3):414-21
Abstract
Although pathogenesis of phenylketonuria is not completely understood, a low phenylalanine diet is effective to prevent severe neurological impairment, mental retardation and behavioural difficulties. Treatment recommendations heavily rely on neuropsychological research; however, single study results are ambiguous, what is reflected in substantial variation of US, British, German, Dutch and French recommendations for blood phenylalanine concentrations for adolescents and adults. We conducted a meta-analysis estimating the influence of age, phenylalanine level, and type of neuropsychological test on effect sizes (standardized differences between controls and patients) of computer-based speed measurements in phenylketonuric patients. The effect of blood phenylalanine level on effect size was more pronounced in children and adolescents than in adults, with choice reaction time being particularly sensitive for phenylalanine concentrations. Results corroborate all recommendations for children. With the exception of the US and Dutch recommendations, all recommendations for adolescents seem to be too liberal. The same effect size is predicted for adult phenylalanine concentrations between 750 and 1500mumol/L not suggesting a preference for any of the published treatment recommendations for adulthood.