The purpose of this study was to examine variability in overarm throwing velocity and spatial output error at various percentages of maximum to test the prediction of an inverted-U function as predicted by impulse-variability theory and a speed-accuracy trade-off as predicted by Fitts’ Law Thirty subjects (16 skilled, 14 unskilled) were instructed to throw a tennis ball at seven percentages of their maximum velocity (40–100%) in random order (9 trials per condition) at a target 30 feet away. Throwing velocity was measured with a radar gun and interpreted as an index of overall systemic power output. Within-subject throwing velocity variability was examined using within-subjects repeated-measures ANOVAs (7 repeated conditions) with built-in polynomial contrasts. Spatial error was analyzed using mixed model regression. Results indicated a quadratic fit with variability in throwing velocity increasing from 40% up to 60%, where it peaked, and then decreasing at each subsequent interval to maximum (p < .001, η2 = .555). There was no linear relationship between speed and accuracy. Overall, these data support the notion of an inverted-U function in overarm throwing velocity variability as both skilled and unskilled subjects approach maximum effort. However, these data do not support the notion of a speed-accuracy trade-off. The consistent demonstration of an inverted-U function associated with systemic power output variability indicates an enhanced capability to regulate aspects of force production and relative timing between segments as individuals approach maximum effort, even in a complex ballistic skill.
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M.A. Urbin, David Stodden, Rhonda Boros, and David Shannon
Shannon Titus Dieringer, David L. Porretta, and Diane Sainato
The purpose of our study was to determine the effect of music (music with lyrics versus music with lyrics plus instruction) relative to on-task behaviors in preschool children with autism spectrum disorder (ASD) in a gross motor setting. Five preschool children (4 boys, 1 girl) diagnosed with ASD served as participants. A multiple baseline across participants in conjunction with an alternating-treatment design was used. For all participants, music with lyrics plus instruction increased on-task behaviors to a greater extent than did music with lyrics. The results of our study provide a better understanding of the role of music with regard to the behaviors of young children with ASD.
Mark Ward, Sarah Gibney, David O’Callaghan, and Sinead Shannon
Despite the benefits, one in three older adults in Ireland has low activity levels. This study examined associations between the local social and built environment and physical activity of older adults to identify age-friendly factors that support physical activity among the aging population. Data were from the population-representative Healthy and Positive Ageing Initiative Age-Friendly City and Counties Survey (N = 10,540). Physical activity was measured using a short-form of the International Physical Activity Questionnaire. Mixed-effects negative binomial regression models were adjusted for known health and sociodemographic correlates of physical activity. Results are reported as unstandardized beta coefficients (β) with standard errors. Loneliness, community participation, and difficulty in accessing green spaces partially explained the differences in the number of minutes that respondents were physically active. Combined with individual-level behavior change interventions, improvements to the local environment and promoting social connectedness may also be useful in promoting physical activity among older adults.
David C. Nieman, Melanie D. Austin, Shannon M. Chilcote, and Laura Benezra
The purpose of this study was to assess the validity and reliability of the MedGem™ device to measure resting metabolic rate (RMR) in children. Subjects included 59 children (29 boys, 30 girls; mean age, 11.0 ± 0.2 y). Subjects were given 4 RMR tests during 1 test session, cconsisting of 2 Douglas bag and 2 MedGem tests, in random counterbalanced order. No significant differences were found between Douglas bag and MedGem systems for oxygen consumption (209 ± 5 and 213 ± 5 mL/min, respectively, P = 0.106, r = 0.911, mean ± standard deviation absolute difference 3.72 ± 17.40 mL/min) or RMR (1460 ± 39 and 1477 ± 35 kcal/d, P = 0.286, r = 0.909, mean ± standard deviation absolute difference 17.4 ± 124 kcal/d). Standard error of estimates for oxygen consumption and RMR were 17.4 mL/min and 124 kcal/d, respectively. In conclusion, these data indicate that the MedGem is a reliable and valid system for measuring oxygen consumption and RMR in children.
Shannon Halloway, JoEllen Wilbur, Michael E. Schoeny, Pamela A. Semanik, and David X. Marquez
This study examined the combined effects of sedentary behavior and moderate-to-vigorous physical activity (MVPA) on cardiovascular health in older Latinos. In a cross-sectional sample of 147 older, community-dwelling Latinos, time spent in sedentary behavior and MVPA were obtained using accelerometers. Analyses examined the effects of a measure of physical activity that combined levels of sedentary behavior (± 10 daily hours) and MVPA (< 30, 30–150, or > 150 weekly minutes) on cardiovascular health outcomes (blood pressure, BMI, waist circumference, cardiorespiratory fitness). Results suggest that cardiovascular health benefits of MVPA on BMI (p = .005), waist circumference (p = .002), and cardiorespiratory fitness (p = .012) may depend on a participant’s level of sedentary behavior. For all three, health benefits of 30–150 weekly minutes of MVPA were found only for those without excessive sedentary behavior (≥ 10 hr). Sedentary behavior may negatively impact cardiovascular health despite moderate participation in MVPA. Health guidelines should suggest reducing sedentary behavior while increasing MVPA.
Lance Ratcliff, Sareen S. Gropper, B. Douglas White, David M. Shannon, and Kevin W. Huggins
This study compared type of habitual exercise and meal form on diet-induced thermogenesis (DIT) in 29 men age 19–28 yr. Resting metabolic rate (RMR) and DIT response to solid-meal (bar) vs. liquid-meal (shake) ingestion were measured via indirect calorimetry; classifications were sedentary (n = 9), endurance trained (n = 11), or resistance trained (n = 9). Height, weight, and body composition (using bioelectrical impedance) were measured for each subject. Energy expenditure was determined before and every 30 min after meal consumption for 210 min. RMR was significantly (p = .045) higher in the endurance- and resistance-trained groups. However, when expressed per kilogram fat-free mass (FFM; relative RMR), differences were not significant. Both DIT (kcal/min) and relative DIT (kcal · min−1 · kg FFM−1) significantly increased with time (p < .0001) from RMR for each meal form. There was no significant exercise-group effect on DIT or relative DIT. There was a significant (p = .012) effect of meal form on DIT; shakes elicited a higher DIT. This significant difference was not found for relative DIT. There was a significant interaction between group and meal form for DIT (p = .008) and relative DIT (p < .0001). Shakes elicited a significantly greater DIT (p = .0002) and relative DIT (p = .0001) in the resistance-trained group. In the sedentary group, relative DIT from shakes was significantly lower than from bars (p = .019). In conclusion, habitual exercise appears to increase RMR, and meal form may impart changes in relative DIT depending on exercise status.