Does learning a skill with the expectation of teaching it impair the skill's execution under psychological pressure if the skill is learned with analogy instructions?

OBJECTIVE: Having learners practice a motor skill with the expectation of teaching it (versus an expectation of being tested on it) has been revealed to enhance skill learning. However, this improvement in skill performance is lost when the skill must be performed under psychological pressure due to 'choking under pressure.' The present study will investigate whether this choking effect is caused by an accrual of declarative knowledge during skill practice and could be prevented if a technique (analogy instructions) to minimize the accrual of declarative knowledge during practice is employed. DESIGN: We will use a 2 (Expectation: teach/test) x 2 (Instruction: analogy/explicit) x 2 (Posttest: high-pressure/low-pressure) mixed-factor design, with repeated measures on the last factor. METHODS: A minimum of 148 participants will be quasi-randomly assigned (based on sex) to one of four groups. Participants in the teach/analogy and teach/explicit groups will practice golf putting with the expectation of teaching putting to another participant, and analogy instructions or explicit instructions, respectively. Participants in the test/analogy and test/explicit groups will practice golf putting with the expectation of being tested on their putting, and analogy instructions or explicit instructions, respectively. The next day all participants will complete low- and high-pressure putting posttests, with their putting accuracy serving as the dependent variable.

Cognitive resources moderate the adverse impact of poor perceived neighborhood conditions on self-reported physical activity of older adults.

Poor neighborhood conditions are associated with lower levels of physical activity for older adults but socio-ecological models posit that physical activity depends on both environmental and individual factors. Older adults' ability to overcome environmental barriers to physical activity may partially rely on cognitive resources. However, evidence on the moderating role of these cognitive resources in the associations between environmental barriers and physical activity is still lacking. We analyzed cross-national and longitudinal data on 28,393 adults aged 50 to 96 years as part of the SHARE. Lack of access to services and neighborhood nuisances were used as indicators of poor neighborhood conditions. Delayed recall and verbal fluency were used as indicators of cognitive resources. Confounder-adjusted generalized estimation equations were conducted to test associations between neighborhood conditions and self-reported moderate physical activity, as well as the moderating role of cognitive resources. Results showed that poor neighborhood conditions reduced the odds of engagement in physical activity. Cognitive resources robustly reduced the adverse influence of poor neighborhood conditions on physical activity. Participants with lower cognitive resource scores showed lower odds of engaging in physical activity when neighborhood conditions were poorer, whereas these conditions were not related to this engagement for participants with higher cognitive resource scores. These findings suggest that cognitive resources can temper the detrimental effect of poor neighborhood conditions on physical activity. Public policies should target both individual and environmental factors to tackle the current pandemic of physical inactivity more comprehensively.

A Comparison of Mental Workload in Individuals with Transtibial and Transfemoral Lower Limb Loss during Dual-Task Walking under Varying Demand.

OBJECTIVES: This study aimed to evaluate the influence of lower limb loss (LL) on mental workload by assessing neurocognitive measures in individuals with unilateral transtibial (TT) versus those with transfemoral (TF) LL while dual-task walking under varying cognitive demand. METHODS: Electroencephalography (EEG) was recorded as participants performed a task of varying cognitive demand while being seated or walking (i.e., varying physical demand). RESULTS: The findings revealed both groups of participants (TT LL vs. TF LL) exhibited a similar EEG theta synchrony response as either the cognitive or the physical demand increased. Also, while individuals with TT LL maintained similar performance on the cognitive task during seated and walking conditions, those with TF LL exhibited performance decrements (slower response times) on the cognitive task during the walking in comparison to the seated conditions. Furthermore, those with TF LL neither exhibited regional differences in EEG low-alpha power while walking, nor EEG high-alpha desynchrony as a function of cognitive task difficulty while walking. This lack of alpha modulation coincided with no elevation of theta/alpha ratio power as a function of cognitive task difficulty in the TF LL group. CONCLUSIONS: This work suggests that both groups share some common but also different neurocognitive features during dual-task walking. Although all participants were able to recruit neural mechanisms critical for the maintenance of cognitive-motor performance under elevated cognitive or physical demands, the observed differences indicate that walking with a prosthesis, while concurrently performing a cognitive task, imposes additional cognitive demand in individuals with more proximal levels of amputation.

Biomechanical and neurocognitive performance outcomes of walking with transtibial limb loss while challenged by a concurrent task.

Individuals who have sustained loss of a lower limb may require adaptations in sensorimotor and control systems to effectively utilize a prosthesis, and the interaction of these systems during walking is not clearly understood for this patient population. The aim of this study was to concurrently evaluate temporospatial gait mechanics and cortical dynamics in a population with and without unilateral transtibial limb loss (TT). Utilizing motion capture and electroencephalography, these outcomes were simultaneously collected while participants with and without TT completed a concurrent task of varying difficulty (low- and high-demand) while seated and walking. All participants demonstrated a wider base of support and more stable gait pattern when walking and completing the high-demand concurrent task. The cortical dynamics were similarly modulated by the task demand for both groups, to include a decrease in the novelty-P3 component and increase in the frontal theta/parietal alpha ratio power when completing the high-demand task, although specific differences were also observed. These findings confirm and extend prior efforts indicating that dual-task walking can negatively affect walking mechanics and/or neurocognitive performance. However, there may be limited additional cognitive and/or biomechanical impact of utilizing a prosthesis in a stable, protected environment in TT who have acclimated to ambulating with a prosthesis. These results highlight the need for future work to evaluate interactions between these cognitive-motor control systems for individuals with more proximal levels of lower limb loss, and in more challenging (ecologically valid) environments.

Cerebral cortical networking for mental workload assessment under various demands during dual-task walking.

While several studies have examined attentional reserve (via event-related potentials) and mental effort (via EEG spectral content) from various cortical regions during dual-task walking, none have assessed changes in the magnitude of interregional (cortico-cortical) communication as a measure of mental workload. Therefore, by deploying a traditional montage of electrode sites centered over the motor planning region as well as a more comprehensive graph theory-based approach encompassing the entire scalp, this study aimed to systematically examine changes in the magnitude of functional connectivity underlying cortico-cortical communication to assess changes in mental workload under various levels of challenge. Specifically, the Weighted Phase Lag Index (WPLI) was computed to assess the changes in magnitude of functional connectivity as participants performed a cognitive task under two demands (low and high) and two conditions (seated and walking). The results revealed enhanced fronto-centro-temporo-parietal theta connectivity during dual-task walking relative to being seated as well as a reduced inhibition of fronto-centro-temporo-parieto-occipital alpha networking as the demand on the secondary cognitive task increased. Collectively, these findings may reflect greater recruitment of task relevant processes to respond to increased cognitive-motor demands and thus an elevation of mental workload in an effort to maintain performance under varying levels of challenge. This work has the potential to inform future mental workload assessment applications in patient populations, including those who employ prostheses during cognitive-motor performance under various task demands.

Saxagliptin restores vascular mitochondrial exercise response in the Goto-Kakizaki rat.

Cardiovascular disease risk and all-cause mortality are largely predicted by physical fitness. Exercise stimulates vascular mitochondrial biogenesis through endothelial nitric oxide synthase (eNOS), sirtuins, and PPARγ coactivator 1α (PGC-1α), a response absent in diabetes and hypertension. We hypothesized that an agent regulating eNOS in the context of diabetes could reconstitute exercise-mediated signaling to mitochondrial biogenesis. Glucagon-like peptide 1 (GLP-1) stimulates eNOS and blood flow; we used saxagliptin, an inhibitor of GLP-1 degradation, to test whether vascular mitochondrial adaptation to exercise in diabetes could be restored. Goto-Kakizaki (GK) rats, a nonobese, type 2 diabetes model, and Wistar controls were exposed to an 8-day exercise intervention with or without saxagliptin (10 mg·kg·d). We evaluated the impact of exercise and saxagliptin on mitochondrial proteins and signaling pathways in aorta. Mitochondrial protein expression increased with exercise in the Wistar aorta and decreased or remained unchanged in the GK animals. GK rats treated with saxagliptin plus exercise showed increased expression of mitochondrial complexes, cytochrome c, eNOS, nNOS, PGC-1α, and UCP3 proteins. Notably, a 3-week saxagliptin plus exercise intervention significantly increased running time in the GK rats. These data suggest that saxagliptin restores vascular mitochondrial adaptation to exercise in a diabetic rodent model and may augment the impact of exercise on the vasculature.

Targeting mitochondria to restore failed adaptation to exercise in diabetes.

Our translational research group focuses on addressing the problem of exercise defects in diabetes with basic research efforts in cell and rodent models and clinical research efforts in subjects with diabetes mellitus. CREB (cAMP-response-element-binding protein) regulates cellular differentiation of neurons, ß-cells, adipocytes and smooth muscle cells; it is also a potent survival factor and an upstream regulator of mitochondrial biogenesis. In diabetes and cardiovascular disease, CREB protein content is decreased in the vascular media, and its regulation in aberrant in ß-cells, neurons and cardiomyocytes. Loss of CREB content and function leads to decreased vascular target tissue resilience when exposed to stressors such as metabolic, oxidative or sheer stress. This basic research programme set the stage for our central hypothesis that diabetes-mediated CREB dysfunction predisposes the diabetes disease progression and cardiovascular complications. Our clinical research programme revealed that diabetes mellitus leads to defects in functional exercise capacity. Our group has determined that the defects in exercise correlate with insulin resistance, endothelial dysfunction, decreased cardiac perfusion and diastolic dysfunction, slowed muscle perfusion kinetics, decreased muscle perfusion and slowed oxidative phosphorylation. Combined basic and clinical research has defined the relationship between exercise and vascular function with particular emphasis on how the signalling to CREB and eNOS [endothelial NOS (nitric oxide synthase)] regulates tissue perfusion, mitochondrial dynamics, vascular function and exercise capacity. The present review summarizes our current working hypothesis that restoration of eNOS/NOS dysfunction will restore cellular homoeostasis and permit an optimal tissue response to an exercise training intervention.

OPTIMAL theory's claims about motivation lack evidence in the motor learning literature.

Motivation is commonly recognized by researchers and practitioners as a key factor for motor learning. The OPTIMAL theory of motor learning (Wulf & Lewthwaite, 2016) claims that practice conditions that enhance learners' expectancies for future successful outcomes or that are autonomy supportive are motivating, thus leading to better learning. To examine the current evidence of the association between motivation and motor learning, we searched the literature for studies that manipulated expectancies and/or autonomy support. Specifically, our goals were to assess whether these manipulations resulted in group differences in motivation and, if so, whether increased motivation was associated with learning advantages. Results showed that out of 166 experiments, only 21% (n = 35) included at least one measure of motivation, even though this is the main factor proposed by OPTIMAL theory to explain the learning benefits of these manipulations. Among those, only 23% (n = 8) found group-level effects on motivation, suggesting that these manipulations might not be as motivating as expected. Of the eight experiments that found a group-level effect on motivation, five also observed learning benefits, offering limited evidence that when practice conditions increase motivation, learning is more likely to occur. Overall, the small number of studies assessing motivation precludes any reliable conclusions on the association between motivation and motor learning from being drawn. Together, our results question whether manipulations implemented in the research lines supporting OPTIMAL theory are indeed motivating and highlight the lack of sufficient evidence in these literatures to support that increased motivation benefits motor learning.

Conquering pressure! The effects of mild-anxiety training on motor performance under pressure during early motor learning.

We conceptually replicated the one previous study (see record 2009-13549-001) revealing that individuals who practice a motor skill under psychological pressure (anxiety training-AT) avoid performance deterioration when exposed to higher levels of pressure. We used a >3× larger sample size than the original study and attempted to shed light on mechanisms whereby AT may promote performance under pressure by measuring variables related to three theories of choking under pressure: attentional control theory (ACT), reinvestment theory, and the biopsychosocial model (BPSM) of challenge and threat. Eighty-four participants practiced 300 golf putts over 2 days with mild psychological pressure manipulations (AT group) or no pressure manipulations (control group). On the third day, all participants completed putting posttests with no pressure manipulations, mild pressure manipulations, or high-pressure manipulations. We had participants report their mental effort, movement reinvestment, and perceived challenge/threat after each posttest to investigate ACT, reinvestment theory, and the BPSM of challenge and threat, respectively. Results showed the AT group maintained their performance across posttests, whereas the control group performed worse under pressure. Additionally, results indicated that AT moderated changes in mental effort and movement reinvestment during pressure, although neither mechanism mediated the relationship between AT and performance under pressure. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Nitric oxide regulates vascular adaptive mitochondrial dynamics.

Cardiovascular disease risk factors, such as diabetes, hypertension, dyslipidemia, obesity, and physical inactivity, are all correlated with impaired endothelial nitric oxide synthase (eNOS) function and decreased nitric oxide (NO) production. NO-mediated regulation of mitochondrial biogenesis has been established in many tissues, yet the role of eNOS in vascular mitochondrial biogenesis and dynamics is unclear. We hypothesized that genetic eNOS deletion and 3-day nitric oxide synthase (NOS) inhibition in rodents would result in impaired mitochondrial biogenesis and defunct fission/fusion and autophagy profiles within the aorta. We observed a significant, eNOS expression-dependent decrease in mitochondrial electron transport chain (ETC) protein subunits from complexes I, II, III, and V in eNOS heterozygotes and eNOS null mice compared with age-matched controls. In response to NOS inhibition with NG-nitro-L-arginine methyl ester (L-NAME) treatment in Sprague Dawley rats, significant decreases were observed in ETC protein subunits from complexes I, III, and IV as well as voltage-dependent anion channel 1. Decreased protein content of upstream regulators of mitochondrial biogenesis, cAMP response element-binding protein and peroxisome proliferator-activated receptor-γ coactivator-1α, were observed in response to 3-day L-NAME treatment. Both genetic eNOS deletion and NOS inhibition resulted in decreased manganese superoxide dismutase protein. L-NAME treatment resulted in significant changes to mitochondrial dynamic protein profiles with decreased fusion, increased fission, and minimally perturbed autophagy. In addition, L-NAME treatment blocked mitochondrial adaptation to an exercise intervention in the aorta. These results suggest that eNOS/NO play a role in basal and adaptive mitochondrial biogenesis in the vasculature and regulation of mitochondrial turnover.

Acute exercise enhances preschoolers' ability to sustain attention.

A growing body of research has illuminated beneficial effects of a single bout of physical activity (i.e., acute exercise) on cognitive function in school-age children. However, the influence of acute exercise on preschoolers' cognitive function has not been reported. To address this shortcoming, the current study examined the effects of a 30-min bout of exercise on preschoolers' cognitive function. Preschoolers' cognitive function was assessed following a single bout of exercise and a single sedentary period. Results revealed that, after engaging in a bout of exercise, preschoolers exhibited markedly better ability to sustain attention, relative to after being sedentary (p = .006, partial eta square = .400). Based on these findings, providing exercise opportunities appears to enhance preschoolers' cognitive function.

Does learning a skill with the expectation of teaching it impair the skill's execution under psychological pressure if the skill is learned with analogy instructions?

OBJECTIVE: Having learners practice a motor skill with the expectation of teaching it (versus an expectation of being tested on it) has been revealed to enhance skill learning. However, this improvement in skill performance is lost when the skill must be performed under psychological pressure due to 'choking under pressure.' The present study investigated whether this choking effect is caused by an accrual of declarative knowledge during skill practice and could be prevented if a technique (analogy instructions) to minimize the accrual of declarative knowledge during practice is employed. DESIGN: We used a 2 (Expectation: teach/test) x 2 (Instructions: analogy/explicit) x 2 (Posttest: low-pressure/high-pressure) mixed-factor design, with repeated measures on the last factor. METHODS: One-hundred fifty-six participants were quasi-randomly assigned (based on sex) to one of four groups. Participants in the teach/analogy and teach/explicit groups practiced golf putting with the expectation of teaching putting to another participant, and analogy instructions or explicit instructions, respectively. Participants in the test/analogy and test/explicit groups practiced golf putting with the expectation of being tested on their putting, and analogy instructions or explicit instructions, respectively. The next day all participants completed low- and high-pressure putting posttests, with their putting accuracy serving as the dependent variable. RESULTS: We observed an Expectation x Instructions × Posttest interaction, such that a main effect of expectation was found in the low-pressure posttest, with the teach group exhibiting superior accuracy, and an Expectation × Instructions interaction was revealed for the high-pressure posttest. This interaction resulted from the teach group showing greater accuracy than the test group exclusively when receiving analogy instructions. CONCLUSION: Results show that participants who practiced with the expectation of teaching exhibited superior learning and indicate that they choked under pressure likely due to their accrual of declarative knowledge during practice, since the choking effect was prevented by having them practice with analogy instructions. Accordingly, having learners practice with the expectation of teaching and techniques that minimize the accrual of declarative knowledge is recommended.

That looks easy! Evidence against the benefits of an easier criterion of success for enhancing motor learning.

OPTIMAL theory predicts providing learners with a relatively easier criterion of success during practice enhances motor learning through increased self-efficacy, perceptions of competence, and intrinsic motivation. However, mixed results in the literature suggest this enhancement effect may be moderated by the number of successes achieved by learners practicing with the difficult criterion. To investigate this possibility, we manipulated quantity of practice to affect the absolute number of successes achieved by learners practicing with different success criteria. Eighty participants were divided into four groups and performed 50 or 100 trials of a mini-shuffleboard task. Groups practiced with either a large or a small zone of success surrounding the target. Learning was assessed 24 h after acquisition with retention and transfer tests. In terms of endpoint accuracy and precision, there were no learning or practice performance benefits of practicing with an easier criterion of success, regardless of the number of trials. This absence of a criterion of success effect was despite the efficacy of our manipulation in increasing the number of trials stopping within the zone of success, self-efficacy, perceptions of competence, and, for participants with 100 trials, intrinsic motivation. An equivalence test indicated that the effect of criterion of success was small, if existent. Moreover, at the individual level, intrinsic motivation did not predict posttest or acquisition performance. There were no benefits of easing the criterion of success on pressure, effort, accrual of explicit knowledge, or conscious processing. These data challenge key tenets of OPTIMAL theory and question the efficacy of easing criterion of success for motor learning.

Relationship between reward-related brain activity and opportunities to sit.

The present study tested whether energy-minimizing behaviors evoke reward-related brain activity that promotes the repetition of these behaviors via reinforcement learning processes. Fifty-eight healthy young adults in a standing position performed a task where they could earn a reward either by sitting down or squatting while undergoing electroencephalographic (EEG) recording. Reward-prediction errors were quantified as the amplitude of the EEG-derived reward positivity. Results showed that reward positivity was larger on reward versus no reward trials, confirming the validity of our paradigm to measure evoked reward-related brain activity. However, results showed no evidence that sitting (versus standing and squatting) trials led to larger reward positivity. Moreover, we found no evidence suggesting that this effect was moderated by typical physical activity, physical activity on the day of the study, or energy expenditure during the experiment. However, at the behavioral level, results showed that the probability of choosing the stimulus more likely to lead to sitting than standing increased as the number of trials increased. In addition, results revealed that the probability of changing the selected stimulus was higher when the previous trial was a stand trial relative to a sit trial. In sum, neural results showed no evidence supporting the theory that opportunities to minimize energy expenditure are rewarding. However, behavioral findings suggested participants tend to choose the less effortful behavioral alternative and were therefore consistent with the theory of effort minimization (TEMPA).

MR angiography of carotid artery aneurysms in a porcine model at 3 Tesla: comparison of two different macrocyclic gadolinium chelates and of dynamic and conventional techniques.

PURPOSE: To evaluate the differences in image quality of two macrocyclic gadolinium-based contrast agents, gadobutrol and gadoterate meglumine, using time-resolved, contrast-enhanced MR angiography (CE-MRA) in a porcine carotid artery aneurysm model and to compare image quality between dynamic and conventional, single acquisition CE-MRA. MATERIALS AND METHODS: Bilateral carotid aneurysms were created surgically in this Institutional Animal Care and Use Committee approved study. Dynamic CE-MRA studies optimized for high temporal resolution were performed at 3 Tesla. Scans using equivalently dosed (on a per mmol basis) gadobutrol and gadoterate meglumine were compared qualitatively and quantitatively in terms of contrast-to-noise ratio (CNR). Higher spatial resolution dynamic and conventional CE-MRA were also compared. RESULTS: N = 16 aneurysms were assessed. Qualitative evaluation of dynamic CE-MRA scans demonstrated a preference for gadobutrol over gadoterate meglumine. Significantly higher aneurysm CNR was found with gadobutrol (133 ± 44) versus gadoterate meglumine, the latter at both equivalent and double injection rates (94 ± 35 and 102 ± 38). In a blinded assessment, conventional CE-MRA was preferred qualitatively when compared with dynamic CE-MRA. However, dynamic CE-MRA was generally capable of providing diagnostic image quality. CONCLUSION: Gadobutrol is preferred to gadoterate meglumine for high temporal resolution dynamic CE-MRA, a fact with important clinical implications for low dose CE-MRA protocols in patients at risk for nephrogenic systemic fibrosis. Conventional high resolution CE-MRA provides superior image quality when compared with dynamic CE-MRA.

Minimally invasive transxiphoid approach to the cardiac apex and caudoventral intrathoracic space.

OBJECTIVE: To describe a minimally invasive surgical technique for procedures involving the caudoventral compartment of the thoracic cavity. STUDY DESIGN: Case series. ANIMALS: Dogs (n = 13). METHODS: Thirteen dogs; undergoing epicardial pacemaker implantation (9), palliative pericardial window (2), perforated right ventricle repair with epicardial pacemaker implantation (1), and peritoneopericardial diaphragmatic hernia (1) were operated by a transxiphoid approach. Dogs were positioned in dorsal recumbency and the bony xiphoid process was dissected free of adjoining tissue and transected proximally and distally. The distal transection was proximal to the cartilaginous junction of the process and the diaphragm. Entry to the thoracic cavity without penetration of the abdomen provided access for surgical treatment. RESULTS: All dogs recovered without complication. No dogs required thoracostomy tube placement. CONCLUSIONS: Transxiphoid approach is minimally invasive and provides adequate exposure for disorders of the caudoventral thoracic cavity.

Increased artery wall stress post-stenting leads to greater intimal thickening.

Since the first human procedure in the late 1980s, vascular stent implantation has been accepted as a standard form of treatment of atherosclerosis. Despite their tremendous success, these medical devices are not without their problems, as excessive neointimal hyperplasia can result in the formation of a new blockage (restenosis). Clinical data suggest that stent design is a key factor in the development of restenosis. Additionally, computational studies indicate that the biomechanical environment is strongly dependent on the geometrical configuration of the stent, and, therefore, possibly involved in the development of restenosis. We hypothesize that stents that induce higher stresses on the artery wall lead to a more aggressive pathobiologic response, as determined by the amount of neointimal hyperplasia. The aim of this investigation was to examine the role of solid biomechanics in the development of restenosis. A combination of computational modeling techniques and in vivo analysis were employed to investigate the pathobiologic response to two stent designs that impose greater or lesser levels of stress on the artery wall. Stent designs were implanted in a porcine model (pigs) for approximately 28 days and novel integrative pathology techniques (quantitative micro-computed tomography, histomorphometry) were utilized to quantify the pathobiologic response. Concomitantly, computational methods were used to quantify the mechanical loads that the two stents place on the artery. Results reveal a strong correlation between the computed stress values induced on the artery wall and the pathobiologic response; the stent that subjected the artery to the higher stresses had significantly more neointimal thickening at stent struts (high-stress stent: 0.197±0.020 mm vs low-stress stent: 0.071±0.016 mm). Therefore, we conclude that the pathobiologic differences are a direct result of the solid biomechanical environment, confirming the hypothesis that stents that impose higher wall stresses will provoke a more aggressive pathobiological response.

A Comparison of Three Different Warm-Ups on 800-Meter Running Performance in Elite Division I Track Athletes - A Pilot Study.

Track and Field athletes perform different types of warm-ups at varying levels of volume and/or intensity prior to competition. Theoretically, this prepares sport specific muscles for activity by increasing muscle temperature, thus mitigating the chance for injury. There is a paucity of information regarding the optimum level for warm-ups regarding maximizing performance in middle distance events. The aim of this study was to examine the effects of three different warm-ups on 800-meter performance. Thirteen Division I student-athletes (seven males and six females) from the Southeastern Conference (SEC) who were middle distance runners participated in this study. We utilized a randomized, cross-over study design to test low, medium, and high-volume warm-up protocols on 800-meter performance. Trials were conducted over a span of three weeks on a SEC University outdoor track. We used a 2 (Sex) x 3 (Warm-Up Protocol) mixed-factor ANOVA, and our results show a main effect of warm-up volume that is not moderated by sex. Post-hoc tests reveal a high-volume warm-up yields superior results for the 800-meter run in comparison to a medium volume warm-up, which provides better results than a low-volume warm-up. These findings may be of value in providing information in program design for coaches on the most effective warm-up protocols for 800-meter runners. Identifying the best warm-up protocol to prime an 800-meter runner for peak performance may not only assist in preventing injury, but enhance performance thus leading to an increased of achievement, and confidence in personal ability.

Exploring the reliability and sensitivity of the EEG power spectrum as a biomarker.

INTRODUCTION: The slope of the electroencephalography (EEG) power spectrum (also referred to as 1/f noise) is an important consideration when calculating narrow-band power. However, psychophysiological data also suggest this slope is a meaningful signal itself, not merely background activity or noise. We present two different methods for quantifying the slope of the power spectrum and assess their reliability and sensitivity. METHODS: We used data from N = 60 participants who had EEG collected during rest, a videogame task, and a second period of rest. At all phases of the experiment, we calculated the "spectral slope" (a regression-based method fit to all datapoints) and the "aperiodic slope" (estimated with the fitting oscillations with 1/f algorithm FOOOF). For both methods we assessed: their reliability, their sensitivity to the transition from rest to task, their sensitivity to changes during the videogame task itself, and the agreement between the two measures. RESULTS: Across resting phases, both spectral and aperiodic slopes showed a high degree of reliability. Both methods also showed a steepening of the power spectrum on-task compared to rest. There was also a high degree of consistency between the two methods in their estimate of the underlying slope, but FOOOF explained more variance in the power spectra across regions and type of activity (rest versus task). CONCLUSION: The slope of the power spectrum is a highly reliable individual difference and sensitive to within-subject changes across two different methods of estimation. Moving forward, we generally recommend the use of the FOOOF algorithm for its ability to account for narrow-band signals, but these data show how regression-based approaches produce similar estimates of the spectral slope, which may be useful in some applications.

Using error-estimation to probe the psychological processes underlying contextual interference effects.

Although the learning benefits of interleaved practice schedules relative to blocked schedules are well-reported, the mechanisms underlying these effects are not fully understood. Researchers have generally suggested that random schedules of practice increase task-related information processing which arises due to switching between variations of the same task (or switching between different tasks). Thus, one potentially useful way to both probe and manipulate contextual interference is to pair it with error estimation during practice. Forced error estimation increases task-related information processing and recording these estimates provides insight into learners' self-awareness of their errors. In the present study, 84 participants were randomly allocated to four groups. Participants practiced a timing task under blocked or random schedules, with and without error estimations prior to feedback. During the acquisition phase, three target times were trained (1500, 1700, 1900 ms), with feedback delivered after every trial. We used delayed post-tests (24 hrs later) to evaluate the retention of these target times and their transfer to two new target times (1600, 1800 ms). Participants who practiced with a random schedule performed worse (i.e., greater absolute error) than those with a blocked schedule during acquisition (p = .006); however, randomly scheduled participants also showed reduced error (p = .004) on the retention and transfer tests. Although prompting error estimations led to greater self-reported mental effort being invested on the task (p = .001), error estimation was not reliably associated with superior learning (p = .133). The accuracy of error estimations did not differ as a function of practice structure (p = .070), although the accuracy of error estimations improved during acquisition (p = .006). Findings highlight the robustness of the contextual interference effect, but we did not find evidence that error estimations moderated the effect on this task. It is in some ways surprising that we found an effect of contextual interference, as past-work suggests that interference effects are attenuated (or eliminated) when participants switch between different parameters of the same task. We speculate that this might be due to the difficulty of the task; even though participants switched between parametric variations of the same task, the distinction between parameters was subtle (i.e., tenths of a second).