The goal of this study was to evaluate the performance of a single video camera system for measuring shoulder rotation during computer work, and to quantify the work and postural space within which the system performs optimally. Shoulder rotation angles calculated using the video system were compared with angles calculated using an active infrared LED three-dimensional motion analysis system while 10 adult volunteers simulated postures for two different trials: typical of normal computer work (freestyle) and with forced shoulder abduction (constrained). Average and absolute errors were calculated to determine the accuracy and precision of the system, respectively, for each trial, for each position, and for both the right and left hands. For the right hand, mean values for the average and absolute errors were –1 and 0 degrees, respectively. Only the absolute error increased significantly to 12 degrees for the constrained posture compared with freestyle. During normal computer work, the video system provided shoulder rotation angle values similar to those of a three-dimensional system, thus making it a viable and simple instrument to use in field studies.
Jennifer L. Bruno, Zhizhong Li, Matthieu Trudeau, Sachin M. Raina and Jack T. Dennerlein
This study assessed the effectiveness of computer-assisted instruction in teaching tennis rules and strategies. The subjects were enrolled in two beginning tennis classes at The Pennsylvania State University. The control group (n=24) received instruction by traditional means. The experimental group (n=19) received no instruction on tennis rules and strategies during regular class periods but did interact with computer-assisted tutorials during two scheduled classes. A written test was used to measure learning and was administered during pretest, posttest, and retest. A two-factor analysis of variance with repeated measures on one factor (ANOVR) was employed to determine significant differences between mean performances. The between-groups analysis and the interaction analysis were not significant, but the within-group analysis revealed an F ratio of 99.72 (p<.001). It was concluded that both groups learned tennis rules and strategies significantly from the pretest to the posttest, their learning performance on the retest differed significantly from pretest administration but not from posttest to the retest, and there was no significant difference between the performance of either group on all three testing occasions.
Jeffrey J. Martin, Nate McCaughtry, Pamela Kulinna, Donetta Cothran and Roberta Faust
The purpose of our study was to examine the impact of mentoring-based professional development on physical education teachers’ efficacy. Experienced mentor teachers were paired (n = 15) with inexperienced protégé teachers (n = 15) at the beginning of a yearlong intervention study. It was hypothesized that teachers would increase their efficacy to use pedometers and computers to enhance instruction, and reduce their computer anxiety. Repeated-measures ANOVAs for mentors and protégés revealed a variety of significant main effects. We found increases in computer and pedometer efficacy. A second set of repeated-measures ANOVAs based on mentors’, protégés’, and control groups’ scores revealed a significant interaction for computer efficacy, indicating that both mentors and protégés significantly increased their computer efficacy compared with the control group. Finally, a significant interaction effect was also found for pedometer efficacy, again indicating that both groups significantly increased their efficacy compared with control teachers.
David J. Sanderson
The purpose of this experiment was to assess the efficacy of using real-time generated computer feedback of a selected biomechanical variable, force, for modifying the pattern-of-force application of inexperienced cyclists while they cycled at a steady rate (60 rpm) and power output (approximately 112 watts). Positive results would imply that the technique of using biomechanical variables as augmented feedback could be applied in a learning study in such a way to train for the enhancement of performance of cyclists. This approach differs from the traditional one of using novices performing novel tasks. Even though the cyclists were inexperienced, they nonetheless knew how to cycle and thus modifications of the pattern of force application were made to an already existing complex skill.
Semyon Slobounov, William Kraemer, Wayne Sebastianelli, Robert Simon and Shannon Poole
The primary purpose of this paper was to demonstrate how modem motion tracking technologies, i.e., the Hock of Birds, and computer visualization graphics may be used in a clinical setting. The idea that joint injury reduces proprioception was investigated, and data for injured subjects were compared to data for noninjured subjects (subjects in all experiments were college students). Two experiments showed that there were no significant losses in joint position sense in knee-injured subjects, and both injured and noninjured groups visually overestimated knee movements. However, injured subjects showed no significant differences when visual reproduction data were compared with actual movement data. In addition, these data indicated that injured subjects may have greater potential for apprehension than noninjured subjects, at least in terms of visual estimation of movement ranges. This is an idea that needs further testing.
Kate Ridley, Jim Dollman and Tim Olds
The aim was to develop and trial a computer delivered multimedia 1-day physical activity questionnaire (CDPAQ) and to compare this with an equivalent hard copy version (HC). Thirty male and female subjects (11.96 ± 0.53 years) were used to assess the validity of the questionnaires by comparing Caltrac counts and heart rate (HR) data with physical activity recalls. Pearson product-moment correlations between the CDPAQ and HR and Caltrac counts ranged from r = 0.36 to 0.63 (p < .05). For the HC, correlations ranged from r = 0.25 to 0.48 (p < .05). While the CDPAQ displayed consistently higher validity correlations, the differences failed to reach statistical significance. Both questionnaires demonstrated high test-retest reliability (r = 0.98, p = .0001). The multimedia features of the CDPAQ may assist children in remembering and characterizing physical activity. The data processing features of the CDPAQ also provide considerable time-saving benefits.
B. Robert Carlson and Thomas L. McKenzie
Data gathering for research on teaching in physical education appears to be heading into a new era, an era in which electronic data collection tools will merge with older measurement techniques to make the processes of storing, analyzing, and transporting data more efficient. The rapid development of microcomputing technology has reached the stage in which portable computers are now practical as state-of-the-art tools for on-site research projects. This article addresses one of the most critical problems for doing research on teaching using time based variables. In the past, when duration recording was the observational technique, there were two ways to collect data: either through multiple stop watches or through interval recording. Both methods have their limitations—one in the manipulation of the several watches and the other in converting interval data to accurate units of time. Outlined in this article is a microcomputer program for on-site duration coding, data analysis, permanent storage, and mainframe support for research on teaching physical education. The system is complex by design but practical to use. It produces total observation time, total time by category, frequency by category, mean length of occurrence, and the percent of total time each category was observed.
MeLisa Creamer, Heather R. Bowles, Belinda von Hofe, Kelley Pettee Gabriel, Harold W. Kohl III and Adrian Bauman
Computer-assisted techniques may be a useful way to enhance physical activity surveillance and increase accuracy of reported behaviors.
Evaluate the reliability and validity of a physical activity (PA) self-report instrument administered by telephone and internet.
The telephone-administered Active Australia Survey was adapted into 2 forms for internet self-administration: survey questions only (internet-text) and with videos demonstrating intensity (internet-video). Data were collected from 158 adults (20–69 years, 61% female) assigned to telephone (telephone-interview) (n = 56), internet-text (n = 51), or internet-video (n = 51). Participants wore an accelerometer and completed a logbook for 7 days. Test-retest reliability was assessed using intraclass correlation coefficients (ICC). Convergent validity was assessed using Spearman correlations.
Strong test-retest reliability was observed for PA variables in the internet-text (ICC = 0.69 to 0.88), internet-video (ICC = 0.66 to 0.79), and telephone-interview (ICC = 0.69 to 0.92) groups (P-values < 0.001). For total PA, correlations (ρ) between the survey and Actigraph+logbook were ρ = 0.47 for the internet-text group, ρ = 0.57 for the internet-video group, and ρ = 0.65 for the telephone-interview group. For vigorous-intensity activity, the correlations between the survey and Actigraph+logbook were 0.52 for internet-text, 0.57 for internet-video, and 0.65 for telephone-interview (P < .05).
Internet-video of the survey had similar test-retest reliability and convergent validity when compared with the telephone-interview, and should continue to be developed.
Klaus Schneider and Ronald F. Zernicke
With a validated mathematical model of the head-neck consisting of nine rigid bodies (skull, seven cervical vertebrae, and torso), we simulated head impacts to estimate the injury risk associated with soccer heading. Experimental data from head-linear accelerations during soccer heading were used to validate the nine-body head-neck model for short duration impact loading of the head. In the computer simulations, the mass ratios between head mass and impacting body mass, the velocity of the impacting body, and the impact elasticity were varied. Head-linear and angular accelerations were compared to standard head-injury tolerance levels, and the injury risk specifically related to soccer heading was estimated. Based on our choice of tolerance levels in general, our simulations showed that injury risk from angular head accelerations was greater than from linear head accelerations, and compared to frontal impacts, lateral impacts had greater angular and less linear head accelerations. During soccer heading, our simulations indicated an unacceptable injury risk caused by angular head accelerations for frontal and lateral impacts at relatively low impact velocities for children, and at medium range impact velocities for adults. For linear head accelerations, injury risk existed for frontal and lateral impacts at medium range to relatively larger impact velocities for children, while no injury risk was shown for adults throughout the entire velocity range. For injury prevention, we suggest that head-injury risk can be reduced most substantially by increasing the mass ratio between head and impacting body. In soccer with children, the mass of the impacting body has to be adjusted to the reduced head mass of a child, that is, it must be clearly communicated to parents, coaches, and youngsters to only use smaller soccer balls.
Hugh Trenchard, Andrew Renfree and Derek M. Peters
Drafting in cycling influences collective behavior of pelotons. Although evidence for collective behavior in competitive running events exists, it is not clear if this results from energetic savings conferred by drafting. This study modeled the effects of drafting on behavior in elite 10,000-m runners.
Using performance data from a men’s elite 10,000-m track running event, computer simulations were constructed using Netlogo 5.1 to test the effects of 3 different drafting quantities on collective behavior: no drafting, drafting to 3 m behind with up to ~8% energy savings (a realistic running draft), and drafting up to 3 m behind with up to 38% energy savings (a realistic cycling draft). Three measures of collective behavior were analyzed in each condition: mean speed, mean group stretch (distance between first- and last-placed runner), and runner-convergence ratio (RCR), which represents the degree of drafting benefit obtained by the follower in a pair of coupled runners.
Mean speeds were 6.32 ± 0.28, 5.57 ± 0.18, and 5.51 ± 0.13 m/s in the cycling-draft, runner-draft, and no-draft conditions, respectively (all P < .001). RCR was lower in the cycling-draft condition but did not differ between the other 2. Mean stretch did not differ between conditions.
Collective behaviors observed in running events cannot be fully explained through energetic savings conferred by realistic drafting benefits. They may therefore result from other, possibly psychological, processes. The benefits or otherwise of engaging in such behavior are as yet unclear.