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Alicia M. Kissinger-Knox, Nicole J. Norheim, Denise S. Vagt, Kevin P. Mulligan and Frank M. Webbe

also that athletes (all male) reported more symptoms when the examiner was female versus male, although the group sizes for this comparison were fairly small (N = 20–30). 10 With technological advancements, computer-based assessments have been integrated into the process of concussion evaluation and

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Behzat B. Kentel, Mark A. King and Sean R. Mitchell

A torque-driven, subject-specific 3-D computer simulation model of the impact phase of one-handed tennis backhand strokes was evaluated by comparing performance and simulation results. Backhand strokes of an elite subject were recorded on an artificial tennis court. Over the 50-ms period after impact, good agreement was found with an overall RMS difference of 3.3° between matching simulation and performance in terms of joint and racket angles. Consistent with previous experimental research, the evaluation process showed that grip tightness and ball impact location are important factors that affect postimpact racket and arm kinematics. Associated with these factors, the model can be used for a better understanding of the eccentric contraction of the wrist extensors during one-handed backhand ground strokes, a hypothesized mechanism of tennis elbow.

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Susan B. Sisson, Stephanie T. Broyles, Birgitta L. Baker and Peter T. Katzmarzyk

Background:

The purposes were 1) to determine if different leisure-time sedentary behaviors (LTSB), such as TV/video/video game viewing/playing (TV), reading for pleasure (reading), and nonschool computer usage, were associated with childhood overweight status, and 2) to assess the social-ecological correlates of LTSB.

Methods:

The analytic sample was 33,117 (16,952 boys and 16,165 girls) participants from the 2003 National Survey of Children’s Health. The cut-point for excessive TV and nonschool computer usage was ≥ 2 hr/day. High quantities of daily reading for pleasure were classified as ≥ 31 min/day. Weighted descriptive characteristics were calculated on the sample (means ± SE or frequency). Logistic regression models were used to determine if the LTSB were associated with overweight status and to examine social-ecological correlates.

Results:

Over 35% of the sample was overweight. Odds of being overweight were higher in the 2 to 3 hr/day (OR: 1.48, 95% CI: 1.24, 1.76) and ≥ 4 hr/day (OR: 1.52, 95% CI: 1.22, 1.91) daily TV groups compared with none. Reading and nonschool computer usage was not associated with being overweight.

Conclusions:

TV was associated with overweight classification; however, nonschool computer usage and reading were not. Several individual, family, and community correlates were associated with high volumes of daily TV viewing.

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Binh Ba Chu, David Lawson and Geraldine Naughton

This study considered the validation of the Computer Science Applications (CSA) activity monitor (model 7164) for predicting activity energy expenditure (EE). A group of 34 Vietnamese adolescents (aged 11 to 15) performed three 5-minute treadmill trials at 4.5, 6.6, and 8.8 km · h−1. Mean activity counts and heart rate (HR) were significantly changed with the three-speed trials (p > 0.05). An equation to predict EE (kcal · min−1) was developed from activity counts and body mass (BM) from the 24 random subjects in Vietnam and was validated on the remaining 10 subjects. This equation explained 72% of the variability in kcal · min−1 (adjusted R2 = 0.72, SEE = 0.91 kcal · min−1). Consistent with previous studies, the relatively high SEE indicates that the equation is more suited for groups of Vietnamese adolescents rather than individuals.

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Audie A. Atienza, Brian Oliveira, B.J. Fogg and Abby C. King

This pilot investigation used portable electronic diaries to assess the physical activity and other health behaviors of 20 adults age 50+ (mean age = 61 years). Study aims were to examine whether computerized cognitive-behavioral strategies could increase adherence to the assessments, the acceptability of electronic diaries to assess everyday health, and the relationship between computerized physical activity assessments with a standardized physical activity measure. Although approximately two thirds of participants had never used an electronic diary, results indicated that a large majority (83%) reported enjoying the use of the electronic diaries, and most (72%) reported enjoying answering all of the health questions. The cognitive-behavioral strategies employed did not enhance assessment adherence, but electronic-diary-based activity levels corresponded more strongly with the poststudy standardized activity measure than the baseline standardized measure, providing evidence of temporal convergence. Findings suggest that the use of portable electronic technology in physical activity assessment of middle-aged and older adults deserves further study.

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Jolene M. Henning, Michelle Lesperance and Jane D. Harris

Column-editor : Malissa Martin

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Corneel Vandelanotte, Ilse De Bourdeaudhuij, Renaat Philippaerts, Michael Sjöström and James Sallis

Background:

The purpose of this study was to examine the reliability and validity of a newly developed computerized Dutch version of the International Physical Activity Questionnaire (IPAQ).

Methods:

Subjects (N = 53) completed the computerized IPAQ at three specified times. Subjects wore a CSA activity monitor during seven full days and simultaneously completed a 7-d physical activity diary. Finally, respondents filled out a paper and pencil IPAQ.

Results:

Intraclass correlation coefficient ranged from 0.60 to 0.83. Correlations for “total physical activity” between the computerized IPAQ and the CSA activity counts were moderate (min: r = 0.38; kcal: r = 0.43). Correlations with the physical activity diary were also moderate (min: r = 0.39; kcal: r = 0.46). Correlations between the computerized and the paper and pencil IPAQ were high (min: r = 0.80; kcal: r = 0.84).

Conclusions:

The computerized Dutch IPAQ is a reliable and reasonably valid physical activity measurement tool for the general adult population.

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Charles F. Cicciarella and Charles B. Corbin

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Karin G.M. Gerritsen, Anton J. van den Bogert, Manuel Hulliger and Ronald F. Zernicke

The purpose of this study was to investigate, theoretically, to what extent muscle properties could contribute to recovery from perturbations during locomotion. Four models with different actuator properties were created: the FLVT model, which encompassed force-length (FL) and force-velocity (FV) characteristics of human muscles as well as muscle stimulation inputs as functions of time (T); the FLT model, which had muscles without force-velocity characteristics; the FVT model, which had muscles without specific force-length characteristics; and the MT model, which had no muscles but was driven by joint moments (M) as a function of time. Each model was exposed to static and dynamic perturbations and its response was examined. FLVT showed good resistance to both static and dynamic perturbations. FLT was resistant to static perturbation but could not counteract dynamic perturbation, whereas the opposite was found for FVT. MT could not counteract either of the perturbations. Based on the results of the simulations, skeletal muscle force-length-velocity properties, although interactively complex, contribute substantially to the dynamic stability of the musculoskeletal system.