Using a lifespan approach, the authors investigated developmental features of the control of ballistic aiming arm movements by manipulating movement complexity, response uncertainty, and the use of precues. Four different age groups of participants (6- and 9-year-old boys and girls and 24- and 73-year-old men and women, 20 participants in each age group) performed 7 types of rapid aiming arm movements on the surface of a digitizer. Their movement characteristics such as movement velocity, normalized jerk, relative timing, movement linearity, and intersegment intervals were profiled. Analyses of variance with repeated measures were conducted on age and task effects in varying movement complexity (Study 1), response uncertainty (Study 2), and precue use (Study 3) conditions. Young children and senior adults had slower, more variant, less smooth, and less linear arm movements than older children and young adults. Increasing the number of movement segments resulted in slower and more variant responses. Movement accuracy demands or response uncertainty interacted with age so that the 6- and 74-year-old participants had poorer performances but responded similarly to the varying treatments. Even though older children and young adults had better performances than young children and senior adults, their arm movement performance declined when response uncertainty increased. The analyses suggested that young children's and senior adults' performances are poorer because less of their movement is under central control, and they therefore use on-line adjustments. In addition, older children and young adults use a valid precue more effectively to prepare for subsequent movements than do young children and senior adults, suggesting that older children and young adults are more capable of organizing motor responses than are young children and senior adults.

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Frequent violations of the assumption that data are normally distributed occur in exercise science and other life and behavioral sciences. When this assumption is violated, parametric statistical analyses may be inappropriate for data analysis. We provide a rationale for using a generalized form of nonparametric analyses based on the Puri and Sen (1985) L treated as a chi 2 approximation. If data do not meet the assumption of normality, this nonparametric approach has substantial power and is easy to use. An advantage of this generalized technique is that ranked data may be used in standard parametric statistical programs widely available on desktop and mainframe computers, for example, regression, analysis of variance (ANOVA), multivariate analysis of variance (MANOVA) within BioMed, SAS, SPSS. Once the data are ranked and analyzed with these programs, the only adjustment required is to use a standard formula to calculate the nonparametric test statistic, L, instead of the parametric test statistic (e.g., F). Thus, rank-order nonparametric models become parallel with their parametric counterparts allowing the researcher to select between them based on characteristics of the data distribution. Examples of this approach are provided using data from exercise science for regression, ANOVA (including repeated measures) and MANOVA techniques from SPSSPC. Using these procedures, researchers can easily examine data distributions and make an appropriate decision about parametric or nonparametric analyses while continuing to use their regular statistical packages.

Purpose:Guided by Stodden et al.’s (2008) conceptual model, the purpose of this study was to examine the associations among perceived competence, actual motor competence (MC), physical activity (PA), and cardiorespiratory fitness in elementary children. The group differences were also investigated as a function of MC levels.Methods:A correlational research design was used in this study. There were 262 children (Mage = 10.87, SD = .77) recruited from three schools in the southern U.S. Students’ MC was objectively measured based on a process-oriented assessment (PE Metrics, NASPE, 2010). Students self-reported perceived competence and leisure-time PA. Then, the Progressive Aerobic Cardiovascular Endurance Run (PACER) and pedometers were used to measure students’ cardiorespiratory fitness and in-class PA, respectively.Results:The structural equation modeling analysis supported the significant indirect effect of the MC on cardiorespiratory fitness and PA through perceived competence. The MANCOVA yielded a significant main effect for MC groups after controlling for sex [Wilks’s Lambda = .838, F = 12.15 (4, 251), p < .001, η2 = .16]. Regardless of sex, children with low MC demonstrated lower perceived competence, PA, and cardiorespiratory fitness compared with children with higher MC (p < .001).Discussion:Development of students’ competence beliefs in PE and certain movement patterns should be emphasized, especially during middle childhood. High quality PE programs must be aligned with national standards, with particular attention to enhancing skill acquisition (standard 1) and PE-motivation (i.e., perceived competence; standard 5).