Patricia L. Weir

Effects of model's skill level and model's knowledge of results on the performance of a dart throwing task

Abstract The experiment was designed to examine how the effects of the models skill level and the models knowledge of results affected performance of an aiming task. Thirty novice, female dart throwers were randomly assigned to six conditions: four groups to complete a 2×2 factorial of models skill level (skilled vs. unskilled) and models knowledge of results (KR vs. No-KR), plus two control groups: one to control for the number of prior task experiences and one to control for the number of practice trials. Practice resulted in more accurate (AE) initial performance than did merely observing a model, and observing a model was not better than receiving no prior task experiences. Subjects observing the skilled model required the models knowledge of results to perform with the same degree of accuracy (AE) as that obtained from observing the unskilled model. Observing the unskilled model resulted in a more consistent (VE) performance throughout practice. There were no performance changes over a 24-hour retention interval. These findings provide preliminary support for the contention that a correct model may not be the best for creating an accurate conceptual representation; and that the effects of observing a model are short lived.

Gender, age, and sport differences in relative age effects among US Masters swimming and track and field athletes

Abstract A relative age effect has been identified in Masters sports (Medic, Starkes, & Young, 2007). Since gender, age, and type of sport have been found to influence the relative age effect in youth sports (Musch & Grondin, 2001), we examined how these three variables influenced possible relative age effects among Masters swimmers and track and field athletes. Using archived data between 1996 and 2006, frequency of participation entries and record-setting performances at the US Masters championships were examined as a function of an individuals constituent year within any 5-year age category. Study 1 investigated the frequency of Master athletes who participated; Study 2 examined the frequency of performance records that were set across constituent years within an age category, while accounting for the distribution of participation frequencies. Results showed that a participation-related relative age effect in Masters sports is stronger for males, that it becomes progressively stronger with each successive decade of life, and that it does not differ across track and field and swimming. In addition, a performance-related relative age effect in Masters sport seems to be stronger for swimming than track and field, but it does not differ across gender and decades of life.

Do or Decline? Comparing the Effects of Physical Inactivity on Biopsychosocial Components of Successful Aging

Research has shown that physical activity (PA) is associated with overall successful aging (SA), but it is unknown whether PA promotes each SA component in similar ways. This cross-sectional population-based cohort study investigates SA in adults aged 60 years+ using data from the Canadian Community Health Survey ( N = 12,042). Multivariate comparisons showed that, compared to those who were PA, physical inactivity was a much stronger associate of functional limitations than either chronic disease or being socially unengaged with life. This effect was not found for moderately active participants. Findings reinforce that PA, even at moderate levels, is an efficient way of optimizing biopsychosocial health, particularly functional health, in later life.

Age-related differences in prehension: the influence of task goals.

A single study is reported in which the influence of age and task goal on reaching and grasping movements were examined. Ten young and 10 elderly subjects reached and grasped a disk (4.5-cm diameter) and then either (a) placed it in a well, (b) placed It in a box, or (c) threw it in a box, all located 30 cm to the left of the disk. The reach-to-grasp movements were analyzed over two phases: the approach to capture the disk and the transporting of the disk. Differential effects were observed over the two phases as a function of age. Over the approach, the movement times of the elderly subjects were comparable with those of the young subjects, but their relative deceleration and hand enclosing times took longer. During object transport, however, the elderly subjects moved more slowly than the young subjects did, but there were no differences in relative timing. In both phases, the precision required of the task influenced the duration of movement and the relative timing of arm deceleration, suggesting that subjects accurately anticipated the demands of the task. Those results, which are discussed in relation to hardware and software limitations on performance, suggest that the age-related differences reflect changes in the use of software strategies over the two phases of movement.

Universal Design: A Step toward Successful Aging

The concept of aging successfully has become increasingly important as demographics shift towards an aging population. Successful aging has been defined to include (1) a low probability of disease and disease-related disability; (2) a high level of physical and cognitive functioning; and (3) an active engagement in life. The built environment can create opportunities or constraints for seniors to participate in social and productive activities. Universally designed spaces are more easily accessed and used by a spectrum of people without specialized adaptations. Thus, a universally designed environment creates opportunities for older adults to participate in these activities without the stigmatization associated with adapted or accessible designs. Providing older adults with specific universal design options (e.g., lever handle faucets) has the potential to increase the ease of completing activities of daily living, which promotes a continual engagement in life. Literature regarding universal design is promising; however, its theory requires further attention from professionals designing the built environment, evidence of the significance of its application from academics, and the embracement of its core principles from society. Overall, universal design has the potential to provide a stepping stone toward successful aging.

Successful Aging across the Years Does One Model Fit Everyone

Rowe and Kahn’s (1987, 1998) model of successful aging (SA) implies a balance among: (1) low probability of disease and disease-related disability; (2) high cognitive and physical functioning; and (3) active engagement with life. This study assessed the relationship of age to the components of SA across the sixth, seventh and eighth decades of life in Canadian seniors (N = 14,749). Age was a significant predictor of disease-related disability and impaired physical functioning, but age had little impact on engagement. Despite health-related changes, these data suggest that the majority of older Canadians are maintaining connections with their community.

Determination of the just noticeable difference (JND) in trunk posture perception

The purpose of this study was to assess the ability of subjects to detect a visual difference between trunk postures. Three groups of participants, ranging from novices to experts, were required to make perceptual discriminations between two trunk postures from a series of image pairs on a computer screen. Images were presented for flexion and lateral bending motions from three different reference postures in both ascending and descending directions. Overall, direction played the largest role, interacting with all other variables. Subjects were most sensitive to changes in the ascending direction, where differences were detected at an average of 2°. In the descending direction, subjects detected differences at an average of 7° between postures. These data have implications for the usability and design of posture matching-based biomechanical software interfaces and the accuracy of peak and cumulative load estimates from models that utilize such interfaces to acquire segment posture inputs.

Monocular and Binocular Vision in the Control of Goal-Directed Movement

Abstract In the present research the authors examined the time course of binocular integration in goal-directed aiming and grasping. With liquid-crystal goggles, the authors manipulated vision independently to the right and left eyes of 10 students during movement preparation and movement execution. Contrary to earlier findings reported in catching experiments (I. Olivier, D. J. Weeks, K. L. Ricker, J. Lyons, & D. Elliott, 1998), neither a temporal nor a spatial binocular advantage was obtained in 1 grasping and 2 aiming studies. That result suggests that, at least in some circumstances, monocular vision is sufficient for the precise control of limb movements. In a final aiming experiment involving 3-dimen- sional spatial variability and no trial-to-trial visual feedback about performance, binocular vision was associated with greater spatial accuracy. Binocular superiority appeared to be most pronounced when participants were unable to adjust their limb control strategy or procedure on the basis of terminal feedback about performance.

Determining the optimal size for posture categories used in video-based posture assessment methods

Currently, there are no standards for the development of posture classification systems used in observation-based ergonomic posture assessment methods. This study was conducted to determine if an optimal posture category size for different body segments and posture views could be established by examining the trade-off between magnitude of error and the number of posture category misclassification errors made. Three groups (trunk flexion/extension and lateral bend; shoulder flexion/extension and adduction/abduction; elbow flexion/extension) of 30 participants each selected postures they perceived to correctly represent the video image shown on a computer screen. For each view, 10 images were presented for five different posture category sizes, three times each. The optimal posture category sizes established were 30° for trunk, shoulder and elbow flexion/extension, 30° for shoulder adduction/abduction and 15° for trunk lateral bend, suggesting that posture category size should be based on the body segment and view of the image being assessed. Across all conditions, the posture category sizes were comparable to those used in published ergonomic tools.

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.