The Effect of Motor Imagery Practice on an Aiming Task with Attentional Focus Cues.

When one directs their attention to an intended effect (external focus of attention, EFOA), motor performance is generally better than when one directs their attention to their own body movements (internal focus of attention, IFOA). However, the effect of attentional focus is unclear when a skill is practiced through motor imagery (MI) in the absence of physical trials. Participants (N = 30, M = 22.33 yrs, SD = 2.69) in the present study completed three physical trials of a reciprocal aiming task before and (24-h) after MI practice. During MI practice, the EFOA (n = 15) and IFOA (n = 15) groups mentally practiced the task with no physical practice with EFOA-MI or IFOA-MI, respectively, for three consecutive days. Our results showed that both groups significantly improved in accuracy (F1,28 = 6.49, p = .017), supporting the benefit of MI in motor skill acquisition. However, a significant effect of attentional focus was not observed (F1.,28 = 0.445, p = 0.51). We discussed two potential explanations: EFOA/IFOA requires physical trials to affect performance, or individuals must use both EFOA and IFOA in the process of creating imagery of the environment and movements, which may obscure the effect of EFOA and IFOA.

Practice-Not Task Difficulty-Mediated the Focus of Attention Effect on a Speed-Accuracy Tradeoff Task.

External focus (attention to the movement effect) has been found effective in motor performance and learning. However, while some investigators have suggested that the effect of attentional focus varies with task difficulty, others reported external focus benefits regardless of difficulty. We hypothesized that attentional focus effects would vary with practice, due to changes in the individual's processing efficiency. We had three 20-person participant groups (external focus instructions, internal focus instructions, control) practice three difficulty levels of a Fitts reciprocal tapping task over two days. Participants in the external/internal focus groups were instructed to "mentally focus on moving the pen/your hand as fast and accurately as possible," while control participants were instructed to "mentally focus only on doing your best to achieve the task goal." We then analyzed the effect of attentional focus by task difficulty at the initial performance (the beginning of the practice) and after learning (the retention/transfer phase), using movement time (MT) and number of error taps (Err) as performance measures. The internal focus group made more errors than the control group only at the retention/transfer phase. We found no error differences between the external and internal focus groups, and there were no MT differences between any groups. Our primary hypothesis about the differential effect of attentional focus by practice was supported. The attentional focus effect on Err differed in the retention/transfer phase from the immediate phase, suggesting that practice mediated the attentional focus effect. We discuss how information theory may supplement understanding of attentional focus interventions in motor skill acquisition.

The autonomy and focus of attention strategies under distraction: Frequency and sample entropy analyses in a dynamic balance task.

An external focus of attention has been shown to be effective in balance tasks. However, replication in applied settings is limited. The OPTIMAL theory proposes that a combination of autonomy and external focus increases focus to the task goal, and therefore more effective than external focus alone. However, research suggests that the combined effect is limited in discrete skills, and the increased focus effect is only reported by subjective assessment. The present study examined the effect of the combined strategy and its effect of "increased focus" compared to external focus and control groups under distraction. In experiment 1, participants (N = 60) practiced eight 35 s trials on a stabilometer followed by a 10 min-delayed retention test and an auditory distraction transfer test. The combined group chose a tape color to place on a stabilometer and was told to "keep the tapes parallel to the floor," the external focus group was yoked with the combined group, and the control group was told to "do your best". Performance was measured in Root Mean Square Error (RMSE). The increased focus effect was examined by both subjective (distraction score, a question about participants' perceptions) and objective (Mean Power Frequency, MPF, Sample entropy, SampEn) methods. Although participants improved significantly (p < .05), group differences were not observed during retention (p's > 0.05). An increased focus effect of the combined effect was not observed in any variables (p's > 0.05). In experiment 2, the practice duration was extended to replicate previous study designs (i.e., 90s trials; 2 days of practice; 24 h retention test; the number of participants). Consistent with experiment 1, group differences were not evident in RMSE, SampEn, and MPF (p's > 0.05). We suggest that autonomy may be required to be task-relevant, and simply telling to do best may be as useful as external focus or combined strategies in a continuous balance task. Further, the analysis showed that SampEn increased on Day 1 but decreased on Day 2, and MPF decreased within a session, but the average MPF increased by the day. Potential explanations and future directions when utilizing these metrics are discussed.

The effect of attentional focus on movement accuracy in an immersive and interactive virtual reality environment.

The effects of attentional focus (AF) instruction were examined in a reciprocal aiming task implemented in a 3-dimensional, fully immersive virtual environment (VE). Within the VE, participants (N = 19) moved a cube between two targets at two paces (750 ms and 500 ms) while being asked to focus externally (EXF) and internally (INF). Performance accuracy was measured as two-dimensional error and its variability between the center of the target to the center of the cube and one-dimensional bias (undershooting/overshooting behavior in the anteroposterior and mediolateral directions). The results indicated better performance, specifically greater accuracy and lower one-dimensional bias in the anteroposterior direction when adopting an EXF compared to an INF. Our findings reveal that the beneficial effects of an EXF on motor performance are not restricted movements within physical environments only but also work in VE. This has implications for rehabilitation and training protocols in VE.

Effects of an external focus of attention and target occlusion on performance in virtual reality.

The use of virtual reality as a training mechanism continues to gain popularity as equipment becomes more readily available. It is important to not only understand the relationship between virtual reality training and motor learning, but to understand the extent to which practice manipulations enhance performance in virtual reality. One common practice manipulation is adopting an external focus of attention, which has been shown to facilitate motor learning in a variety tasks. The purposes of the present study were to investigate the effectiveness of an external focus of attention and the effects of target occlusion times in virtual reality. Fifty-six participants performed a single-leg long jump during baseline, training, and retention and were randomly assigned to either an external or control group. During baseline and retention, all participants performed the task in both a virtual reality (VR) and real world (RW) environments. Training was all done in VR where participants were provided an external focus cue or no cue. Results revealed that individuals jumped significantly further in RW than VR in both baseline and retention (p < .001). During training, the external group jumped significantly further than control (p < .05). These results suggest that the adoption of an external focus improves performance during training. However, we did not see a benefit of an external focus in retention. These findings should be taken into consideration when using virtual reality as a training tool when performance must be transferred to a real world environment.

The Effects of Using Imagery to Elicit an External Focus of Attention.

Background: An external focus of attention has been shown to be superior to adopting an internal focus of attention in a variety of motor skills. Purpose: To examine the efficacy of directing attention externally toward an imagined object when performing the standing long jump. This form of practice was compared to a group of participants that practiced the same motor skill while directing their attention toward an object that was physically present in the practice environment. Method: All participants performed a series of standing long-jumps on a rubber mat. Participants were randomly assigned to either an external focus condition where they were instructed to jump as close as possible to a cone that was directly in front of them. Or they were assigned to an imagery condition in which they were instructed to jump toward an imagined cone. Following acquisition trials, a 24-hr retention and transfer test was completed by all participants. Results: Significant improvement was demonstrated by both groups during acquisition, retention and transfer phases compared to the baseline measure. However, no significant differences were observed between the two experimental conditions. Conclusion: The findings of this experiment demonstrate that attention directed externally toward a physical object and an imagined object has a similar effect.

The Effects of Attentional Focus Instructions Specific to Body Movements on Movement Quality and Performance.

Contexts: Directing an individual's attention to the effect of the movements (external focus) has been shown to improve performance than directing attention to body movements (internal focus). However, the effect of attentional focus instructions specific to movement quality has not been investigated thoroughly. OBJECTIVE: To compare the effects of internal and external focus instructions specific to body movements. DESIGN: Mixed design, 2 (sex) × 2 (instructions). SETTINGS: Laboratory setting. PARTICIPANTS: A total of 40 participants (males, n = 20; mean [SD]; age = 22.0 [2.19] y; height = 179.33 [5.90] cm; mass = 77.7 [13.04] kg; females, n = 20; age = 22.0 [3.87] y; height = 164.84 [5.80] cm; mass = 71.48 [20.66] kg) were recruited. INTERVENTION: Participants completed 2 consecutive jumps (ie, a forward jump from a height and then a maximal vertical jump) with internal focus and external focus instructions. External focus was elicited by placing pieces of tape on the participants' legs. MAIN OUTCOME MEASURES: Landing quality was measured by the Landing Error Scoring System to assess movement quality, and the vertical jump height was measured by Vertec. RESULTS: The performance results showed that the external focus condition resulted in superior vertical jump height compared with the internal focus condition (P < .05). Although landing quality did not show significant differences between 2 conditions, the effect size (η2 = .09) indicated that landing quality was better when participants adopted an external, rather than an internal focus of attention (P = .07). CONCLUSIONS: The body-oriented instructions can be provided externally by adding artificial external cues and directing attention to them. Importantly, the findings were evident in a qualitative assessment that can be adopted by practitioners. The results suggest that practitioners should adopt an external focus cue for performance and also consider using an external focus for movement quality.

Motor Behavior Literature Fails to Translate: A Preliminary Investigation into Coaching and Focus of Attention in Recreational Distance Runners.

The benefits of using an external focus relative to an internal focus for endurance activities are well documented. However, literature has revealed that internally focused instructions are predominantly adopted in the field, and existing data are limited to highlyskilled level populations. Moreover, athletes' focus of attention during fatigue invoking activities is unknown. The purpose of the current study was to examine what type of feedback and instructions experienced recreational individuals receive and their self-adopted focus of attention when fatigued. Distance runners answered a questionnaire related to instruction and feedback from coaches and thoughts that the athletes experienced while fatigued. The results showed that more than half of the instructions runners received from coaches were internally focused and consisted of both knowledge of performance and knowledge of results. Self-reported focus of runners when fatigued revealed that only 15% of task-related thoughts were externally focused. Despite a large body of motor behavior literature, attentional strategies shown to increase performance and learning were not predominantly present (from coaches or self-adopted) for this population of experienced recreational distance runners.

The Effects of Attentional Focus on Brain Function During a Gross Motor Task.

CONTEXT: Although the beneficial effects of using an external focus of attention are well documented in attainment and performance of movement execution, neural mechanisms underlying external focus' benefits are mostly unknown. OBJECTIVE: To assess brain function during a lower-extremity gross motor movement while manipulating an internal and external focus of attention. DESIGN: Cross-over study. SETTING: Neuroimaging center Participants: A total of 10 healthy subjects (5 males and 5 females) Intervention: Participants completed external and internal focus of attention unilateral left 45° knee extension/flexion movements at a rate of 1.2 Hz laying supine in a magnetic resonance imaging scanner for 4 blocks of 30 seconds interspersed with 30-second rest blocks. During the internal condition, participants were instructed to "squeeze their quadriceps." During the external condition, participants were instructed to "focus on a target" positioned above their tibia. MAIN OUTCOME MEASURES: T1 brain structural imaging was performed for registration of the functional data. For each condition, 3T functional magnetic resonance imaging blood oxygenation level dependent data representing 90 whole-brain volumes were acquired. RESULTS: During the external relative to internal condition, increased activation was detected in the right occipital pole, cuneal cortex, anterior portion of the lingual gyrus, and intracalcarine cortex (Zmax = 4.5-6.2, P < .001). During the internal relative to external condition, increased activation was detected in the left primary motor cortex, left supplementary motor cortex, and cerebellum (Zmax = 3.4-3.5, P < .001). CONCLUSIONS: Current results suggest that an external focus directed toward a visual target produces more brain activity in regions associated with vision and ventral streaming pathways, whereas an internal focus manipulated through instruction increases activation in brain regions that are responsible for motor control. Results from this study serve as baseline information for future prevention and rehabilitation investigations of how manipulating focus of attention can constructively affect neuroplasticity during training and rehabilitation.

The effects of instructional cues on performance and mechanics during a gross motor movement.

Externally focused instructions specific to performance have shown to improve body mechanics (Gokeler et al., 2015; Welling, Benjaminse, Gokeler, & Otten, 2016). However, the effect of using an external focus instruction may have been more profound if the content of the instruction had been relevant to mechanics. Therefore, the present study examined the effects of externally focused instructions specific to performance and externally focused instructions specific to body mechanics on mechanics and performance. Twenty-four adults (n = 12 males; n = 12 females) performed a series of drop jumps following external focus cues that were specific to performance and landing mechanics. Participants completed a drop jump followed by a maximal effort vertical jump. The initial contact, maximal angle, and range of motion at the knee in the sagittal and frontal plane motion were measured for mechanics and the height of the second vertical jump was measured for performance. The results suggest external focus instructions specific to performance are beneficial for performance, but not for improving landing mechanics. This suggests that external focus instructions must be specific to the contents of the instruction.

The Influence of Attentional Focus on Balance Control over Seven Days of Training.

This study examined the training effect of attentional focus (external focus, internal focus, or no focus instructions) on a dynamic balance task. Participants completed baseline balance testing, seven consecutive days of dynamic balance board training, and retention testing 24 hours after the last session. The novel finding of this study was the presence of a training effect on balance control when adopting an external focus relative to an internal focus or no focus instructions. Further, we report the unique observation that more patterned behavior was adopted regardless of the focus instructions. These findings provide insight into how instructions can be altered to enhance human balance control and complement the constrained-action hypothesis.

Postural Control Entropy Is Increased When Adopting an External Focus of Attention.

Falls in older adults are a public health challenge due to their influence on well-being and health-care costs. One way to address this challenge is to discover new methods to enhance postural control in older adults so they are better prepared to maintain an upright stance. Older and younger adults (N = 32) performed a static balance task on a force plate with no instructions, internal focus instructions, or external focus instructions. Center of pressure displacement time series were analyzed using sample entropy and standard deviation. Only the external focus condition significantly increased postural control entropy, which was observed across both age groups. This study showed that an external focus of attention can be used to increase postural control entropy within a single session of testing.

An External Focus of Attention is Effective for Balance Control when Sleep-deprived.

The purpose of our study was to examine if the beneficial effects of an external focus are effective for balance control when sleep-deprived. Sleep-deprived participants (27 hours awake) completed three blocks of five separate 30 second trials on a dynamic balance board. All participants were given internal, external, and control instruction. For the internal focus trials, participants focused on their feet; whereas, for the external focus trials, participants focused on the balance board. Participants' time in balance was significantly greater during the external focus compared to the internal focus and control. These findings suggest that external focus instructions are effective when participants are sleep-deprived.

The effects of low-intensity cycling on cognitive performance following sleep deprivation.

This study examined the effect of 24h of sleep deprivation on cognitive performance and assessed the effect of acute exercise on cognitive performance following sleep deprivation. Young, active, healthy adults (n=24, 14 males) were randomized to control (age=24.7±3.7years, BMI=27.2±7.0) or exercise (age=25.3±3.3years, BMI=25.6±5.1) groups. Cognitive testing included a 5-min psychomotor vigilance task (PVT), three memory tasks with increasing cognitive load, and performance of the PVT a second time. On morning one, cognitive testing followed a typical night's sleep. Following 24-h of sustained wakefulness, cognitive testing was conducted again prior to and after the acute intervention. Participants in the exercise condition performed low-intensity cycling (∼40%HRR) for 15-min and those in the control condition sat quietly on the bike for 15-min. t-Tests revealed sleep deprivation negatively affected performance on the PVT, but did not affect memory performance. Following the acute intervention, there were no cognitive performance differences between the exercise and rested conditions. We provide support for previous literature suggesting that during simple tasks, sleep deprivation has negative effects on cognitive performance. Importantly, in contrast to previous literature which has shown multiple bouts of exercise adding to cognitive detriment when combined with sleep deprivation, our results did not reveal any further detriments to cognitive performance from a single-bout of exercise following sleep deprivation.

Skill-based changes in motor performance from attentional focus manipulations: a kinematic analysis.

In the present paper, expert and novice law enforcement officers performed a handgun shooting task under varied attention-demanding conditions; outcome (i.e. accuracy, consistency) and movement kinematics were measured (i.e. within and between-trial variability (BTV) of forearm and upper arm absolute angle). Using a dual-task paradigm, we directed participants' attention towards either a skill-relevant aspect of movement execution or to a skill-irrelevant distractor and compared their data to a single-task control condition. The results showed that experts' BTV in their upper arm increased during dual-tasks relative to control, but performance was similar across all three conditions. In contrast, novices' performance was poorer during both dual-tasks relative to control, but limited changes in movement kinematics were observed. This data suggests that attention demanding situations trigger experts' ability to adapt their movement pattern to maintain end-point control. The data for novices are less clear. Implications for future research are discussed. Practitioner Summary: Expert and novice law enforcement officials completed a shooting task under baseline and attention-demanding situations. Experts outperformed novices under all conditions, but exhibited increased variability in their upper arm position while shooting during attention-demanding compared to baseline conditions. Novices' movement data remained variable throughout all conditions. The data suggest that experts are able to maintain shooting performance during an attention-demanding situation by adopting a functional movement strategy.

MOTOR IMAGERY, PHYSICAL PRACTICE, AND MEMORY: THE EFFECTS ON PERFORMANCE AND WORKLOAD.

-The theoretical explanations used to explain changes in performance during motor imagery and physical practice conditions are inconsistent when memory retrieval is and is not required. This study measured performance time and workload during acquisition, a retention test requiring memory retrieval, and a retention test not requiring memory retrieval using a key-pressing task. The participants were assigned to physical practice with or without instructions to learn or motor imagery with or without instructions to learn. A diagram of the keys was presented during the practice trials and the first retention test, but was not presented during the second test. The results revealed no effect for the learning instructions or performance changes during the practice phases. However, during both retention tests participants in the physical practice conditions performed significantly faster than those in the motor imagery conditions. Also, higher levels of workload were reported for the motor imagery conditions when the retention test required memory retrieval compared to the other phases. A discussion of the implications of workload on performance is presented with respect to varying practice conditions.

Influence of practice schedules and attention on skill development and retention.

Focus of attention during dual-tasks and practice schedules are important components of motor skill performance and learning; often studied in isolation. The current study required participants to complete a simple key-pressing task under a blocked or random practice schedule. To manipulate attention, participants reported their finger position (i.e., skill-focused attention) or the pitch of an auditory tone (i.e., extraneous attention) while performing two variations of a dual-task key-pressing task. Analyses were conducted at baseline, 10 min and 24h after acquisition. The results revealed that participants in a blocked schedule, extraneous focus condition had significantly faster movement times during retention compared to a blocked schedule, skill focus condition. Furthermore, greatest improvements from baseline to immediate and delayed retention were evident for an extraneous attention compared to the skill-focused attention, regardless of practice schedule. A discussion of the unique benefits an extraneous focus of attention may have on the learning process during dual-task conditions is presented.

Fine and gross motor skills: The effects on skill-focused dual-tasks.

Dual-task methodology often directs participants' attention towards a gross motor skill involved in the execution of a skill, but researchers have not investigated the comparative effects of attention on fine motor skill tasks. Furthermore, there is limited information about participants' subjective perception of workload with respect to task performance. To examine this, the current study administered the NASA-Task Load Index following a simulated shooting dual-task. The task required participants to stand 15 feet from a projector screen which depicted virtual targets and fire a modified Glock 17 handgun equipped with an infrared laser. Participants performed the primary shooting task alone (control), or were also instructed to focus their attention on a gross motor skill relevant to task execution (gross skill-focused) and a fine motor skill relevant to task execution (fine skill-focused). Results revealed that workload was significantly greater during the fine skill-focused task for both skill levels, but performance was only affected for the lesser-skilled participants. Shooting performance for the lesser-skilled participants was greater during the gross skill-focused condition compared to the fine skill-focused condition. Correlational analyses also demonstrated a significant negative relationship between shooting performance and workload during the gross skill-focused task for the higher-skilled participants. A discussion of the relationship between skill type, workload, skill level, and performance in dual-task paradigms is presented.

Interpretation of postural control may change due to data processing techniques.

Postural control is commonly assessed by quantifying center of pressure (CoP) variability during quiet stance. CoP data is traditionally filtered prior to analysis. However, some researchers suggest filtering may lead to undesirable consequences. Further, sampling frequency may also affect CoP analysis, as filtering CoP signals of different sampling frequencies may influence variability metrics. This study examined the influence of sampling frequency and filtering on metrics that index the magnitude and structure of variability in CoP displacement and velocity. Healthy adults (N=8, 27.4±2.6 years) balanced on their right foot for 60s on a force plate. CoP data recorded at 100Hz was then downsampled and/or filtered (2nd order dual-pass 10Hz low-pass Butterworth) to create six different CoP time series for each participant: (1) original, (2) filtered, (3) downsampled to 50Hz, (4) downsampled to 25Hz, (5) downsampled to 50Hz and filtered, and (6) down-sampled to 25Hz and filtered. Data were then analyzed using four common variability metrics (standard deviation [SD], root mean square [RMS], detrended fluctuation analysis α [DFA α], and sample entropy [SampEn]). Data processing techniques did not influence the magnitude of variability (SD and RMS), but did influence the structure of variability (DFA α and SampEn) in CoP displacement. All metrics were influenced by data processing techniques in CoP velocity. Thus, when interpreting changes in CoP variability, one must be careful to identify how much change is driven by the neuromotor system and how much is a function of data processing technique.

Effects of mental practice in novice learners in a serial positioning skill acquisition.

The effects of mental practice in novices were investigated. University students (N = 60) performed a serial aiming task, distributed in 5 groups of 12: mental practice, physical practice, mental-physical practice (first mental then physical practice), physical-mental practice (first physical then mental practice), and a control group that only performed the tests. Participants transported three tennis balls among six containers in a pre-established sequence in a target time. In the acquisition phase and retention test (24 hr. later), the task was the same; in the transfer test, 5 min. after the acquisition phase, sequence and time changed. Six trials were performed in the acquisition phase, and each test consisted of 9 trials. The performance measures were absolute error, constant error, and variable error; a t test and a two-way ANOVA were used to compare the acquisition phase and tests, respectively. Physical practice and both groups of combined conditions presented better performance in tests than the mental practice and control groups. Mental practice without motor experience in the task did not improve motor learning. Prior physical performance is desirable before conducting mental practice.