A remotely delivered, peer-led intervention to improve physical activity and quality of life in younger breast cancer survivors.

Younger breast cancer survivors (YBCS) consistently report poorer quality of life (QOL) than older survivors. Increasing physical activity (PA) may improve QOL, but this has been understudied in YBCS. This single arm pilot study evaluated the feasibility and acceptability of a 3-month, peer-delivered, remote intervention to increase PA and improve QOL in YBCS. Data were collected from October 2019 - July 2020. Participants (n = 34, 43.1 ± 5.5 years old, 46 ± 34.4 months post-diagnosis, BMI = 30.2 ± 7.4 kg/m2) completed six video sessions with a trained peer mentor; self-monitored PA with a Fitbit activity tracker; and interacted with a private Fitbit Community for social support. At baseline, 3-and 6-months, participants completed QOL questionnaires and PA was measured through accelerometer (moderate-to-vigorous PA [MVPA]) and self-report (strength and flexibility). A parallel mixed-methods approach (qualitative interviews and quantitative satisfaction survey at 3-months) explored intervention feasibility and acceptability. One-way repeated-measures ANOVAs examined impacts on PA and QOL at 3-and 6-months. The intervention was feasible as evidenced by efficient recruitment, high retention, and adherence to intervention components. Remote delivery, working with a peer mentor, and using Fitbit tools were highly acceptable. From baseline to 3-months, participants increased time spent in objectively measured MVPA, strength, and flexibility exercises, and reported meaningful improvements to body image, fatigue, anxiety, and emotional support. A fully remote, peer-to-peer intervention is an acceptable and promising strategy to increase PA and improve QOL in YBCS. Refinements to the intervention and its delivery should be further assessed in future studies, toward the goal of disseminating an evidence-based, scalable intervention to the growing number of YBCS.Trial registration Prospectively registered as NCT04064892.

Comparison of blood flow restriction devices and their effect on quadriceps muscle activation.

OBJECTIVES: Blood flow restriction training (BFRT) provides an alternative approach to traditional strength training. The purpose of this study was to determine differences in quadriceps muscle activation, subject reported pain, and perceived exertion between three exercise conditions: low-load resistance BFRT with (1) regulated and (2) standardized devices, and (3) high-load resistance exercise without BFRT. DESIGN: Randomized cross over study. SETTING: XX University Biomechanics laboratory. PARTICIPANTS: Thirty-four healthy subjects (18 male/16 female) each completed three randomized sessions of knee extensions using Delfi's Personalized Tourniquet System (R) at 30% of 1 repetition maximum (1RM), the B-Strong™ device (S) at 30% 1RM, and high-load resistance exercise (HL) at 80% 1RM. MAIN OUTCOME MEASURES: Quadriceps EMG activity, numeric pain rating scale (NPRS), and perceived exertion (OMNI-RES) were recorded. RESULTS: Average and peak EMG were greater in HL sessions than both S and R (p < .001). NPRS was greater in the R sessions compared to both S (p < .001) and HL (p < .001). OMNI-RES was greater in the R sessions compared to S (p < .02) and HL (p < .001). No differences (p > .05) in average or peak EMG activation were found between S and R sessions. CONCLUSIONS: Quadriceps EMG amplitude was greater during high-load resistance exercise versus low-load BFR exercise and there were no differences in EMG findings between BFRT devices.

Stand Up Now: A Sedentary Behavior Intervention in Older Adults of Moderate to Low Physical Function.

OBJECTIVES: To examine the efficacy of an the intervention Stand Up Now (SUN) to reduce sedentary behavior (SB) and improve physical function and mobility. METHODS: SUN included two groups: (a) focused on reducing total SB (SUNSL) and (b) focused on increasing sit-to-stand (STS) transitions (SUNSTS). The participants (N = 71; Mage = 87 ± 7 years) had 12 weekly health coaching sessions. SB, physical function, and mobility were measured at the baseline, 6, and 12 weeks via the activPAL, Short Physical Performance Battery, and the 8-foot up and go, respectively. Linear mixed models examined the outcome variables over time. RESULTS: Both groups decreased sedentary time (1.3 ± 0.3 hr, p < .001), increased standing time (0.5 ± 0.2 hr, p < .02), and improved physical function (1.5 ± 0.4 points, p < .001) from the baseline to 6 weeks, and they maintained it at 12 weeks. SUNSTS increased STS transitions (5.4 ± 4.1, p < .001), while SUNSL had no changes (0.5 ± 3.1, p > .9). There were no changes in mobility for either group (0.5 ± 1.5 s, p > .05). DISCUSSION: SUN demonstrates the efficacy to improve SB and physical function in older adults.

Motivation for Physical Activity among U.S. Adolescents: A Self-Determination Theory Perspective.

BACKGROUND: Promoting adolescent physical activity is crucial as this marks a time when physical activity rates decline. PURPOSE: This study examined motivation for physical activity from a self-determination theory (SDT) perspective in a large sample of adolescents in the USA across three settings: in school, out of school, and on weekends. METHODS: Participants (N = 1,661) were adolescents from the National Cancer Institute's Family Life, Activity, Sun, Health, and Eating study. Participants had a mean age of 14.47 (standard deviation = 1.61) and were 50.2% female. In this national sample balanced to match the U.S. population on several key demographics, 64.2% were non-Hispanic White. Analyses included three linear regression models in which estimated weekly minutes of moderate-to-vigorous physical activity (MVPA) in school, out of school, and on weekends were entered as dependent variables. Five forms of motivation (intrinsic, integrated, identified, introjected, and external) were entered simultaneously as independent variables. Age, body mass index, gender, and race/ethnicity were also included as covariates. RESULTS: All models were significant. For MVPA in school, external regulation, introjected regulation, identified regulation, and intrinsic motivation were positively associated with MVPA. For MVPA out of school, external regulation, introjected regulation, identified regulation, integrated regulation, and intrinsic motivation were positively associated with MVPA. For MVPA on weekends, integrated regulation, and intrinsic motivation were positively associated with MVPA. CONCLUSIONS: The relationship between motivation and MVPA varies across settings. These findings have important implications for motivating adolescents to engage in physical activity and may inform future interventions aimed at increasing physical activity.

Effects of a Community-Based Exercise Program on Older Adults' Physical Function, Activities of Daily Living, and Exercise Self-Efficacy: Feeling Fit Club.

Community-based exercise programs have demonstrated feasibility, yet many lack controlled studies examining their efficacy. This study examined the efficacy of a community-based exercise program, using a controlled design. Participants (N = 262, Mage = 74.0 years, SD = 8.4) were women (77%) and men recruited from senior centers served by the county Area Agency on Aging. Intervention participants (n = 133) were newly enrolled in classes. Controls (n = 129) were recruited from matched sites not offering classes. Validated measures of physical function, exercise self-efficacy, balance, and activities of daily living (ADL) confidence were administered at baseline and 3 months. Significant improvements in upper and lower body strength, aerobic endurance, mobility, exercise self-efficacy, and balance were found in the exercisers but not controls. No changes in ADL confidence occurred in exercisers, while significant decreases occurred in controls. Findings support the efficacy of the county-wide program. Building an evidence base for community-delivered programs should provide impetus for increased dissemination through state and national agencies thereby increasing program impact.

An Autoimmune Protocol Diet Improves Patient-Reported Quality of Life in Inflammatory Bowel Disease.

BACKGROUND: Prior studies suggest dietary modification may improve clinical response or remission rates in patients with inflammatory bowel disease (IBD). Our aim was to examine whether an autoimmune protocol diet improves quality of life in patients with active Crohn disease (CD) and ulcerative colitis (UC). METHODS: We conducted an uncontrolled clinical trial of the autoimmune protocol diet in adult patients with active IBD (Harvey-Bradshaw Index ≥ 5 for CD or partial Mayo score ≥ 3 for UC, and erosions/ulcers on endoscopy and/or elevated fecal calprotectin). The dietary intervention consisted of a 6-week elimination phase, followed by a 5-week maintenance phase. Short Inflammatory Bowel Disease Questionnaire (SIBDQ) was completed at baseline, and weeks 3, 6, 9, and 11. RESULTS: The final cohort included 6 UC and 9 CD participants. Mean SIBDQ score improved significantly from baseline (46.5) to weeks 3 (54.0, P = 0.02), 6 (53.3, P = 0.02), 9 (62.0, P = 0.03), and 11 (60.5, P = 0.05). Among participants completing all 5 surveys, mean SIBDQ increased from 46.5 to 61.5 by week 11 (P = 0.03). By week 3, participants experienced significant improvements in bowel movement frequency (36%, P = 0.04), stress (28%, P = 0.01), and ability to perform leisure/sport activities (29%, P = 0.02). Effects were not significantly different between CD and UC participants. CONCLUSIONS: Dietary modification can improve quality of life as early as week 3 in patients with active IBD. Larger randomized controlled trials are needed to examine dietary interventions in IBD.

BTrackS Balance Test for Concussion Management is Resistant to Practice Effects.

OBJECTIVE: Recent guidelines advocate for ongoing balance testing in the assessment of management of concussion injuries. This study sought to determine whether the Balance Tracking System (BTrackS) provides stable balance results over repeated administration and, thus, is a reliable tool for concussion management. DESIGN: Repeated measures and test-retest reliability. SETTING: University Biomechanics Laboratory. PARTICIPANTS: Random sample of 20 healthy young adults. INTERVENTIONS: Force plate balance testing using BTrackS on days 1, 3, 8, and 15. MAIN OUTCOME MEASURES: Practice-induced changes in the average center of pressure excursion over 4 repeated administrations of the BTrackS Balance Test (BBT). Test-retest reliability of center of pressure excursion from day 1 to day 15. RESULTS: No significant practice-induced balance differences were found across testing days (P > 0.4), and test-retest reliability of the BBT was excellent from day 1 to day 15 (R 0.92). CONCLUSIONS: These findings indicate that the BBT does not elicit a practice effect over repeat administrations. BTrackS provides excellent reliability and objectivity, which can increase clinician accuracy when monitoring sport-related concussions.

The Association Between Self-Reported Adherence to Physical Activity Recommendations and Criteria for Maintaining Physical Independence of Older Adults.

While physical activity (PA) improves functions for activities of daily living, little is known of the association between meeting published PA Guidelines for Americans (PAGA) and meeting published physical function guidelines for maintaining independence. The purpose of this study was to examine the association between meeting the PAGA and meeting independence criteria on the Senior Fitness Tests (SFT). Older adults (N = 265) completed SFTs, assessing cardiorespiratory fitness, lower and upper body strength, mobility, and self-reported aerobic and resistance PA. Chi-square tests and logistic regressions examined associations between meeting PAGA and SFT independence criteria. A significant relationship was found between meeting aerobic PAGA and cardiorespiratory and upper body SFT criteria; a significant relationship was found between meeting resistance PAGA and upper body strength criteria. Although research suggests that PAGA are effective in maintaining fitness in older adults when PA is structured and monitored, mixed results were found for self-reported PA and SFT criteria.

Validity and Reliability of a Portable Balance Tracking System, BTrackS, in Older Adults.

BACKGROUND AND PURPOSE: Falls are the leading cause of disability, injury, hospital admission, and injury-related death among older adults. Balance limitations have consistently been identified as predictors of falls and increased fall risk. Field measures of balance are limited by issues of subjectivity, ceiling effects, and low sensitivity to change. The gold standard for measuring balance is the force plate; however, its field use is untenable due to high cost and lack of portability. Thus, a critical need is observed for valid objective field measures of balance to accurately assess balance and identify limitations over time. The purpose of this study was to examine the concurrent validity and 3-day test-retest reliability of Balance Tracking System (BTrackS) in community-dwelling older adults. Minimal detectable change values were also calculated to reflect changes in balance beyond measurement error. METHODS: Postural sway data were collected from community-dwelling older adults (N = 49, mean [SD] age = 71.3 [7.3] years) with a force plate and BTrackS in multitrial eyes open (EO) and eyes closed (EC) static balance conditions. Force sensors transmitted BTrackS data via a USB to a computer running custom software. Three approaches to concurrent validity were taken including calculation of Pearson product moment correlation coefficients, repeated-measures ANOVAs, and Bland-Altman plots. Three-day test-retest reliability of BTrackS was examined in a second sample of 47 community-dwelling older adults (mean [SD] age = 75.8 [7.7] years) using intraclass correlation coefficients and MDC values at 95% CI (MDC95) were calculated. RESULTS: BTrackS demonstrated good validity using Pearson product moment correlations (r > 0.90). Repeated-measures ANOVA and Bland-Altman plots indicated some BTrackS bias with center of pressure (COP) values higher than FP COP values in the EO (mean [SD] bias = 4.0 [6.8]) and EC (mean [SD] bias = 9.6 [12.3]) conditions. Test-retest reliability using intraclass correlation coefficients (ICC2.1 was excellent (0.83) and calculated MDC95 for EO (9.6 cm) and EC (19.4 cm) and suggested that postural sway changes of these amounts are meaningful. DISCUSSION: BTrackS showed some bias with values exceeding force plate values in both EO and EC conditions. Excellent test-retest reliability and resulting MDC95 values indicated that BTrackS has the potential to identify meaningful changes in balance that may warrant intervention. CONCLUSION: BTrackS is an objective measure of balance that can be used to monitor balance in community-dwelling older adults over time. It can reliably identify changes that may require further attention (eg, fall-prevention strategies, declines in physical function) and shows promise for assessing intervention efficacy in this growing segment of the population.

Relationships between physical activity, food choices, gender and BMI in Southern Californian teenagers.

Given the increased prevalence of pediatric obesity and risk of developing chronic disease, there has been great interest in preventing these conditions during childhood by focusing on healthy lifestyle habits, including nutritious eating and physical activity (PA). The purpose of this study was to determine the relationship between PA, body mass index (BMI) and food choices in adolescent males and females. This cross-sectional study, using a survey questionnaire, evaluated 1212 Southern Californian adolescents' self-reported PA, BMI and food frequency. Results revealed that even though males are more active than females, they have higher BMI percentile values (p < 0.05). Females consumed salad, vegetables and fruit more frequently than males (p < 0.05), where males consumed hamburgers, pizza, red meat, processed meat, eggs, fish, fruit juice, soda and whole milk more frequently than females (p < 0.05). Overweight/obese teens consumed red meat, processed meat and cheese more frequently than healthy weight teens (p < 0.05), yet there was no difference in PA between healthy and overweight/obese teens. These results demonstrate that higher levels of PA may not counteract an unhealthy diet. Even though PA provides numerous metabolic and health benefits, this study suggests that healthy food choices may have a protective effect against overweight and obesity. Healthy food choices, along with PA, should be advocated to improve adolescent health by encouraging maintenance of a healthy weight into adulthood.

A Longitudinal Assessment Of Standing Balance In Healthy Adults.

Background/Study Context: The study was a longitudinal assessment of age-related changes in standing balance and response strategy usage in healthy adults. METHODS: Balance of 17 individuals with a mean age of 44.5 years was assessed and then reassessed 19.5 years later. Participants stood on computer-controlled dual-force platforms enclosed by a visual surround and completed six tests in which visual and/or somatosensory information was systematically degraded or eliminated. RESULTS: Results for each test and a weighted composite balance score revealed no significant change in postural control over the time period studied. However, response strategy scores indicated some significant change with age. Specifically, compensatory movement corrections about the ankle complex increased when standing on a stable support surface with and without vision, and hip-centered corrections were prominent when standing on an unstable surface with eyes open or closed. CONCLUSION: Increased reliance on response strategy usage with time is interpreted as a compensatory adjustment to age-related increases in postural instability and accounts for the absence of any change in standing balance under different conditions of sensory input.

Understanding the Capacity for Exercise in Post-Bariatric Patients.

PURPOSE: The aim of this study is to conduct a pilot randomized trial testing an exercise program specifically adapted for post-bariatric patients. METHODS: A total of 51 post-bariatric patients, 6-24 months post-surgery, were randomly assigned to usual care control (n = 25) or the exercise intervention (n = 26). The intervention included twice weekly 60-min group exercise classes with functional strength, flexibility, and aerobic activities; at least 3 days per week of self-directed exercise; daily pedometer; recording of steps and activities; and weekly telephone counseling. There was also a 6-month maintenance period. RESULTS: Patients were 49 ± 12 years old, 84 % female, 59 % non-Hispanic white, with a BMI of 32.9 ± 5.7 kg/m2 and percent excess BMI loss since surgery of 56 ± 35 %. Patients were 14 ± 5 months post-surgery. A total of 44 patients (86 %) completed both phases of the program and all assessments. The following measures improved significantly for intervention participants with no significant change in control participants: yards walked in 6 min, seconds for 8-foot up-and-go, number of arm curls, and distance in inches for chair sit-and-reach. Intervention changes remained after 6 months of maintenance. CONCLUSIONS: When compared to patients in usual care, a specially adapted exercise program for post-bariatric patients resulted in significant improvements in objectively monitored health outcomes. This program was delivered in a clinical setting and could be implemented in a variety of settings to improve health outcomes for post-bariatric patients.

Wii Fit exer-game training improves sensory weighting and dynamic balance in healthy young adults.

The Nintendo Wii Fit is a balance training tool that is growing in popularity due to its ease of access and cost-effectiveness. While considerable evidence now exists demonstrating the efficacy of the Wii Fit, no study to date has determined the specific mechanism underlying Wii Fit balance improvement. This paucity of knowledge was addressed in the present study using the NeuroCom Balance Manager's Sensory Organization Test (SOT) and Limits of Stability (LOS) test. These well-recognized posturography assessments, respectively, measure sensory weighting and dynamic stability mechanisms of balance. Forty healthy, young participants were recruited into two groups: Wii Fit Balance Intervention (WFBI) (n=20) and Control (CON) (n=20). Balance training consisted of seven Wii Fit exer-games played over the course of six consecutive weeks (2-4×/week, 30-45min/day). The WFBI group performed Neurocom testing before and after the intervention, while the CON group was tested along a similar timeline with no intervention. Mixed-design ANOVAs found significant interactions for testing time point and condition 5 of the SOT (p<0.02), endpoint excursion (p<0.01), movement velocity (p<0.02), and response time (p<0.01). These effects were such that greater improvements were seen for the WFBI group following Wii Fit training. These findings suggest that individuals with known issues regarding the processing of multiple sources of sensory information and/or who have limited functional bases of support may benefit most from Wii Fit balance training.

An alternative to the balance error scoring system: using a low-cost balance board to improve the validity/reliability of sports-related concussion balance testing.

OBJECTIVE: Recent guidelines advocate sports medicine professionals to use balance tests to assess sensorimotor status in the management of concussions. The present study sought to determine whether a low-cost balance board could provide a valid, reliable, and objective means of performing this balance testing. DESIGN: Criterion validity testing relative to a gold standard and 7 day test-retest reliability. SETTING: University biomechanics laboratory. PARTICIPANTS: Thirty healthy young adults. ASSESSMENT OF RISK FACTORS: Balance ability was assessed on 2 days separated by 1 week using (1) a gold standard measure (ie, scientific grade force plate), (2) a low-cost Nintendo Wii Balance Board (WBB), and (3) the Balance Error Scoring System (BESS). MAIN OUTCOME MEASURES: Validity of the WBB center of pressure path length and BESS scores were determined relative to the force plate data. Test-retest reliability was established based on intraclass correlation coefficients. RESULTS: Composite scores for the WBB had excellent validity (r = 0.99) and test-retest reliability (R = 0.88). Both the validity (r = 0.10-0.52) and test-retest reliability (r = 0.61-0.78) were lower for the BESS. CONCLUSIONS: These findings demonstrate that a low-cost balance board can provide improved balance testing accuracy/reliability compared with the BESS. CLINICAL RELEVANCE: This approach provides a potentially more valid/reliable, yet affordable, means of assessing sports-related concussion compared with current methods.

Using step cadence goals to increase moderate-to-vigorous-intensity physical activity.

BACKGROUND: Increasing moderate-to-vigorous-intensity physical activity (MVPA) is an important public health goal. Pedometers are evidence-based devices for increasing daily activity, but studies have not evaluated the comparative efficacy of step cadence goals for increasing MVPA. PURPOSE: This study aimed to evaluate the efficacy of three pedometer-based step goals for increasing MVPA. METHODS: Latina women (n = 180; 18-55 yr, mean body mass index = 31.1, SD = 6.5) were recruited to 12 community centers, which were randomly assigned to one of three conditions. Each group received an identical 12-wk theory-based physical activity (PA) intervention that differed only on the type of daily step goal: 1) a self-selected goal (SELF); 2) a goal of 10,000 steps per day (FREQUENCY); or 3) a goal of 3000 steps in 30 min (CADENCE). Accelerometer-based PA was measured at baseline and after 12 wk. RESULTS: Adjusted multilevel pattern-mixture models using generalized estimating equations revealed that participants in the CADENCE condition engaged in similar levels of postintervention MVPA to those in the SELF and FREQUENCY goal conditions. However, MVPA of participants in the CADENCE condition was more likely to occur in bouts lasting greater than 10 consecutive minutes compared with the MVPA of participants in the SELF (P = 0.01) or FREQUENCY (P = 0001) conditions. CONCLUSIONS: PA interventions should consider including a step cadence goal to help individuals accumulate bout-based MVPA and meet national PA guidelines.

Children with heavy prenatal alcohol exposure experience reduced control of isotonic force.

BACKGROUND: Heavy prenatal alcohol exposure can result in diverse and extensive damage to the central nervous system, including the cerebellum, basal ganglia, and cerebral cortex. Given that these brain regions are involved in the generation and maintenance of motor force, we predicted that prenatal alcohol exposure would adversely affect this parameter of motor control. We previously reported that children with gestational alcohol exposure experience significant deficits in regulating isometric (i.e., constant) force. The purpose of this study was to determine whether these children exhibit similar deficits when producing isotonic (i.e., graded) force. METHODS: Children with heavy prenatal alcohol exposure and typically developing children completed a series of isotonic force contractions by exerting force on a load cell to match a criterion target force displayed on a computer monitor. Two levels of target force (5 or 20% of maximum voluntary force) were investigated in combination with varying levels of visual feedback. RESULTS: Compared with control children, children with heavy prenatal alcohol exposure generated isotonic force signals that were less accurate, more variable, and less complex in the time domain. Specifically, interactions were found between group and visual feedback for response accuracy and signal complexity, suggesting that these children have greater difficulty altering their motor output when visual feedback is low. CONCLUSIONS: These data suggest that prenatal alcohol exposure produces deficits in regulating isotonic force, which presumably result from alcohol-related damage to developing brain regions involved in motor control. These children will most likely experience difficulty performing basic motor skills and daily functional skills that require coordination of finely graded force. Therapeutic strategies designed to increase feedback and, consequently, facilitate visual-motor integration could improve isotonic force production in these children.

Evaluation of a multi-component group exercise program for adults with arthritis: Fitness and Exercise for People with Arthritis (FEPA).

BACKGROUND: Research supports the favorable effects of exercise on physical and psychosocial outcomes in those with arthritis. Few easily disseminated, multi-component, arthritis-specific programs have been evaluated using both physical function and psychosocial measures. Fitness and Exercise for People with Arthritis (FEPA) is a new community-based, 3-month, instructor supervised multi-component exercise program for individuals with arthritis designed to increase strength, flexibility, balance, and aerobic conditioning, while emphasizing joint-protection and proper biomechanics. PURPOSE: To conduct a preliminary evaluation of the effects of the FEPA program on physical function and arthritis-related outcomes in individuals with arthritis. METHOD: Middle-aged (n = 31, M(age) = 54.8 ± 7.2) and older (n = 79, M(age) = 76.0 ± 6.6) adults with arthritis completed the instructor led FEPA program in community senior centers, churches, and adult education settings. Changes in physical function, measured using the arm curl, back-scratch test, 8-foot up-and-go, and 6 min walk and self-reported arthritis-related pain, perceived physical function, affect, and self-efficacy for symptom management were assessed using RM ANOVA. RESULTS: Significant improvements (ps < .05) in all physical function measures were found in the older group. In the middle-aged group, significant improvements (ps < .05) were found in the 8-foot up-and-go and 6 min walk. Self-reported physical function, pain perceptions, and self-efficacy for pain management significantly improved (ps < .05) in middle-aged participants, while only self-reported pain perceptions significantly improved in the older group. CONCLUSIONS: FEPA shows promise for improving health-related outcomes in those with arthritis, and has potential for sustainability in community settings.

Children with heavy prenatal alcohol exposure exhibit deficits when regulating isometric force.

BACKGROUND: Production of isometric (i.e., constant) force is an essential component of performing everyday functional tasks, yet no studies have investigated how this type of force is regulated in children with confirmed histories of heavy prenatal alcohol exposure. METHODS: Children 7 to 17 years old with heavy prenatal alcohol exposure (n = 25) and without exposure (n = 18) applied force to a load cell to generate an isometric force that matched a criterion target force displayed on a computer monitor. Two levels of target force were investigated in combination with 3 levels of visual feedback frequency that appeared on the computer monitor as a series of yellow dots. Force was maintained for 20 seconds and participants completed 6 trials per test condition. RESULTS: Root-mean-square error, signal-to-noise ratio, and sample entropy indexed response accuracy, response variability, and signal complexity, respectively. The analyses revealed that in comparison with controls, children with gestational ethanol exposure were significantly less accurate and more variable in regulating their force output and generated a response signal with greater regularity and less complexity in the time domain. CONCLUSIONS: Children with prenatal alcohol exposure experience significant deficits in isometric force production that may impede their ability to perform basic motor skills and activities in everyday tasks.

Co-regulation of movement speed and accuracy by children with heavy prenatal alcohol exposure.

The study investigated how children with heavy prenatal alcohol exposure regulate movement speed and accuracy during goal-directed movements. 16 children ages 7 to 17 years with confirmed histories of heavy in utero alcohol exposure, and 21 nonalcohol-exposed control children completed a series of reciprocal tapping movements between two spatial targets. 5 different targets sets were presented, representing a range of task difficulty between 2 and 6 bits of information. Estimates of percent error rate, movement time, slope, and linear fit of the resulting curve confirmed that for goal-directed, reciprocal tapping responses, performance of the group with prenatal alcohol exposure was described by a linear function, as predicted by Fitts' law, by sacrificing movement accuracy. The index of performance was the same for the two groups: it initially increased, then leveled off for more difficult movements.