Nancy McNevin

The automaticity of complex motor skill learning as a function of attentional focus

The present experiment was designed to test the predictions of the constrained-action hypothesis. This hypothesis proposes that when performers utilize an internal focus of attention (focus on their movements) they may actually constrain or interfere with automatic control processes that would normally regulate the movement, whereas an external focus of attention (focus on the movement effect) allows the motor system to more naturally self-organize. To test this hypothesis, a dynamic balance task (stabilometer) was used with participants instructed to adopt either an internal or external focus of attention. Consistent with earlier experiments, the external focus group produced generally smaller balance errors than did the internal focus group and responded at a higher frequency indicating higher confluence between voluntary and reflexive mechanisms. In addition, probe reaction times (RTs) were taken as a measure of the attention demands required under the two attentional focus conditions. Consistent with the hypothesis, the external focus participants demonstrated lower probe RTs than did the internal focus participants, indicating a higher degree of automaticity and less conscious interference in the control processes associated with the balance task.

EMG Activity as a Function of the Performer's Focus of Attention

In previous studies of attentional focus effects, investigators have measured performance outcome. Here, however, the authors used electromyography (EMG) to determine whether differences between external and internal foci would also be manifested at the neuromuscular level. In 2 experiments, participants (N = 11, Experiment 1; N = 12, Experiment 2) performed biceps curls while focusing on the movements of the curl bar (external focus) or on their arms (internal focus). In Experiment 1, movements were performed faster under external than under internal focus conditions. Also, integrated EMG (iEMG) activity was reduced when performers adopted an external focus. In Experiment 2, movement time was controlled through the use of a metronome, and iEMG activity was again reduced under external focus conditions. Those findings are in line with the constrained action hypothesis (G. Wulf, N. McNevin, & C. H. Shea, 2001), according to which an external focus promotes the use of more automatic control processes.

Attentional focus on supra-postural tasks affects postural control

We examined whether the attentional focus adopted on a supra-postural task has an influence on postural control. Similar to Riley, Stoffregen, Grocki, and Turvey (Human Movement Science 18 (1999) 795), participants were instructed to stand still while lightly touching a loosely hanging sheet with their fingertips. However, instructions varied slightly under two conditions: Participants were either asked to minimize movements of the finger (internal focus) or to minimize movements of the sheet (external focus). In contrast to Riley et al.s findings, both touch conditions resulted in increased postural sway, compared to a baseline condition (no touch). However, in line with previous findings (e.g., Wulf, McNevin, & Shea, Quarterly Journal of Experimental Psychology 54A (2001) 1143), frequency of responding (fast Fourier transformation) was greater under the external focus condition, compared to both internal focus and baseline conditions. The findings indicate improved static balance responses under external focus conditions and compromised static balance response under internal focus conditions.

Attentional focus on suprapostural tasks affects balance learning

We examined whether the attentional focus induced by a suprapostural task has an influence on the learning of a dynamic balance task. Participants balanced on a stabilometer and were required to hold a tube horizontal with both hands. In Experiment 1, the tube contained a table tennis ball, whereas it was empty in Experiment 2. Participants were instructed to focus on either their hands (internal focus) or the tube (external focus). We measured balance performance as a function of attentional focus on the suprapostural task. Participants practised for 2 days, and on Day 3 they performed a retention test (with tube) and a transfer test (without tube). In both experiments, the external focus groups demonstrated more effective retention and transfer than the internal focus groups (and than the control group in transfer in Experiment 2). In addition, in Experiment 1 the external group was superior in keeping the tube horizontal. This suggests that the performers attentional focus regarding the suprapostural task affects performance and learning not only of the suprapostural task itself, but also of the postural task.

Reciprocal influences of attentional focus on postural and suprapostural task performance.

The authors examined the influence that attentional focus on either a postural or a suprapostural task had on the performance of each task. Participants (N = 32) stood on an inflated rubber disk and held a pole horizontally. All participants performed under 4 attentional focus conditions: external (disk) or internal (feet) focus on the postural task, and external (pole) or internal (hands) focus on the suprapostural task. Compared with internal focuses, external focuses on either task resulted in similar and reduced postural sway. Response frequency on each task increased when participants focused on the respective task. Finally, an external focus on either task produced higher frequencies of responding on the suprapostural task. The authors conclude that suprapostural task goals have a stronger influence on postural control than vice versa, reflecting the propensity of the motor system to optimize control processes on the basis of the desired movement effect.

Effects of Tyrosine, Phentermine, Caffeine D-amphetamine, and Placebo on Cognitive and Motor Performance Deficits During Sleep Deprivation

Abstract Cognitive and motor performance are critical in many circumstances and are impaired by sleep deprivation. We administered placebo, tyrosine 150 mg/kg, caffeine 300 mg/70 kg, phentermine 37.5 mg and d-amphetamine 20 mg at 15.30 h following overnight sleep deprivation and compare their effects on cognitive and motor performance in healthy young men. Tests of visual scanning, running memory, logical reasoning, mathematical processing, the Stroop task, four-choice serial reaction time, time wall take, pursuit tracking, visual vigilance, Trails (B) task and long-term memory were evaluated at standardized intervals before, during and after sleep deprivation and drugs. Performance decrements with sleep deprivation occurred in visual scanning, running memory, logical reasoning, mathematical processing, the Stroop test, the time wall test, tracking and visual vigilance. Interestingly, with sleep deprivation some tests improved and others did not deteriorate. Improvements with medication following sleep deprivation were seen in running memory, logical reasoning, mathematical processing, tracking and visual vigilance. Although less effective than d-amphetamine, tyrosine improved performance on several tests. We conclude that all drugs tested improved at least some aspects of cognitive and motor performance after sleep deprivation. As a naturally occurring amino acid, and thus amenable to nutritional strategies, tyrosine may deserve further testing.

Effects of Resistance Training on Functional Ability in Elderly Individuals

Purpose. Determine the effects of 16 weeks of strength training on measures of functional ability in elderly who are functionally limited. Design. Quasi-experimental trial in which elderly volunteers were assigned to either an exercise group or a control group. Participants. Eighty-seven participants (65–93 years) living independently but with some functional limitations. Intervention. Thirteen different strength training exercises using Thera-Band resistive bands (Hygenic Corporation, Akron, Ohio). The program was 16 weeks in duration, and the frequency was three times per week. Participants exercised in a group setting one time per week and were given a home exercise book to follow for two additional sessions per week. Measures. Functional ability was operationalized to include a variety of measures related to functional ability that impact activities of daily living, morbidity, and mortality in the elderly, including upper- and lower-body strength and gait. Analysis. Intervention effects were analyzed using a 2 (groups: exercise group vs. control group) X 3 (time: baseline vs. mid vs. post) analysis of variance. Results. The exercise group demonstrated significant improvements in upper-body strength as measured by biceps curl (F[2,140] = 39.870; p < .05) and lower-body strength as measured by chair sit-to-stand (F[2,124] = 25.887; p < .05). Gait velocity (F[2,140] = 37.317; p < .05) and step length (F[2,140] = 4.182; p < .05) both increased for the exercise group at week 9, but this increase disappeared by week 17. Compared with minimal changes in the control group, the exercise group demonstrated significant improvements in upper-body strength as measured by biceps curl and lower-body strength as measured by chair sit-to-stand. Conclusion. Some measures of function ability were improved after a 16-week structured exercise program for functionally limited elderly. Because functional ability has been inversely correlated with short-term morbidity and the need for assisted living among older adults, providing opportunities to exercise is crucial to future functioning and independence of the elderly population. (Am J Health Promot 2011;25[4]:237–243.)

Exercise and Functional Tasks Among Adults Who Are Functionally Limited

This study compared the efficacy of 16 weeks of either resistance training, aerobic walking, or combined resistance training and aerobic walking on the performance of functional tasks among adults age 65 years and older with limited functional ability. One hundred thirty-one older adult individuals were randomized into four groups: resistance training, aerobic walking, combined resistance and aerobic walking groups, or a nonexercise control group. Each of the exercise groups documented 70% compliance with their respective exercise intervention, which included three weekly exercise sessions. At baseline, and 8 and 16 weeks following baseline, all participants completed six assessments of their functional ability. Analysis of covariance indicated that all three exercise intervention groups significantly improved measures of functional ability, with the resistance group demonstrating the most consistent gains over the six measures. These findings indicate that older adults who are functionally limited can improve their functional ability through a variety of types of exercise.

Barriers Are Not the Limiting Factor to Participation in Physical Activity in Canadian Seniors

The identification of barriers to physical activity and exercise has been used for many decades to explain exercise behavior in older adults. Typically health concerns are the number one barrier to participation. Data from CCHS-HA dataset (N = 20, 875) were used to generate a sample of Canadians, 60+ years, who did not identify a health condition limitation, illness, or injury as a barrier to participation in physical activity (n = 4,900) making this dataset unique in terms of the study of barriers to participation. While the vast majority of older adults participated in physical activity, 9.4% did not. The relationships between nonparticipation, barriers, self-reported health status, and chronic health conditions were determined using binary logistic regression. The main findings suggest that traditional barriers and self-reported health status are not responsible for nonparticipation. Nonparticipation was best predicted by chronic health conditions suggesting a disconnect between self-reported health status and underlying health conditions. The data are clear in suggesting that barriers are not the limiting factor and physical activity programming must be focused on meeting the health needs of our aging population.

Effects of attentional focus and age on suprapostural task performance and postural control.

Purpose: Suprapostural task performance (manual tracking) and postural control (sway and frequency) were examined as a function of attentional focus, age, and tracking difficulty. Given the performance benefits often found under external focus conditions, it was hypothesized that external focus instructions would promote superior tracking and reduced postural sway for both age groups, most notably as a function of tracking difficulty. Method: Postural sway, frequency of postural adjustments, and tracking accuracy under two levels of task difficulty were assessed for younger (M age = 20.98 years) and older (M age = 70.80 years) participants while they manually tracked a pursuit-rotor target. Participants received instructions to focus on either their actions (internal focus) or the effect of their actions (external focus). Results: Analyses revealed a beneficial effect of an external focus on suprapostural performance on the less-difficult (0.5 Hz) tracking task, and this performance was associated with a modest improvement in medial-lateral postural sway. Conclusion: The findings offer limited support for external focus-of-attention benefits under a mildly challenging tracking task. While older adults tend to adopt a conservative postural control strategy regardless of tracking task difficulty, external focus instructions on a suprapostural task promoted a modest, beneficial shift in postural control.