Bone remodeling as a response to exercise in human subjects is described in the literature, although most studies treat exercise as a qualitative factor contributing to bone remodeling. Quantitative description requires assessment of the mechanical loads on the bones. This work describes a generalized lower extremity model that uses existing musculoskeletal modeling techniques to quantify mechanical variables in the femoral neck during exercise. An endurance exercise program consisting of walking, jogging jumping rope, and weight-training was analyzed. Peak femoral neck cortex stresses and strains were high during jogging and squatting, compared to walking, whereas jumping rope and other weight-training exercises produced peak stresses comparable to or lower than walking. Peak stress and strain rates were significantly higher for walking, jumping rope, and jogging than for weight-training. The model should prove useful for any study investigating a quantitative relationship between exercise and bone remodeling.
David D. Anderson, Ben M. Hillberry, Dorothy Teegarden, William R. Proulx, Connie M. Weaver and Tomoaki Yoshikawa
Zakkoyya H. Lewis, Kyriakos S. Markides, Kenneth J. Ottenbacher and Soham Al Snih
We investigated the relationship between physical activity and physical function on the risk of falls over time in a cohort of Mexican-American adults aged 75 and older from the Hispanic Established Population for the Epidemiologic Study of the Elderly (H-EPESE). Participants were divided into four groups according to their level of physical activity and physical function: low physical activity and low physical function (n = 453); low physical activity and high physical function (n = 54); high physical activity and low physical function (n = 307); and high physical activity and high physical function (n = 197). Using generalized linear equation estimation, we showed that participants with high physical activity and low physical function had a greater fall risk over time, followed by the high physical activity and high physical function group. Participants seldom took part in activities that improve physical function. To prevent falls, modifications to physical activity should be made for older Mexican Americans.
Walter E. Davis, William A. Sparrow and Terry Ward
A fractionation technique was employed to determine the locus of reaction time delay in Down syndrome (DS) and other adult subjects with mental retardation (MH). Twenty-three subjects (8 nondisabled, 8 MH, and 7 DS) responded to a light, sound, and combination light/sound signal. Dependent measures of premotor time, motor time, total reaction time, and movement time were obtained during a 20° elbow extension movement and were analyzed separately. As expected, both MH and DS subjects were slower and more variable in their responses than the subjects without disabilities. In turn, DS subjects were significantly slower but not more variable than the MH subjects. There were no significant differences between the DS and MH subjects on movement times. Evidence for both a specific (premotor) and a generalized (both premotor and motor) locus of delay was found. Some difference in signal effect was also found for the DS subjects.
Karen Davranche, Danny Paleresompoulle, Rémy Pernaud, Julie Labarelle and Thierry Hasbroucq
The present study investigated the effects of acute paddling on performance in a typical decision-making task. It was aimed at assessing whether the effects of moderate exercise can be replicated using the feet as response effectors when physical exercise essentially solicits upper-body muscles. Twelve national-level paddling athletes performed a Simon task while paddling at a moderate (75% of maximal heart rate, HRmax) and at very light (40% of HRmax) intensities. The results showed that the effects of moderate exercise can be generalized to exercises involving different response effectors and upper-body muscle groups. They suggest (1) that the activation-suppression hypothesis (Ridderinkhof, 2002) holds when the task is performed with the feet, and (2) that moderate exercise speeds up reaction time and impairs the suppression of direct response activation.
Youngdeok Kim, Ilhyeok Park and Minsoo Kang
The purpose of this study was to investigate rater effects on the TGMD-2 when it applied to children with intellectual disability. A total of 22 children with intellectual disabilities participated in this study. Children’s performances in each of 12 subtests of the TGMD-2 were recorded via video and scored by three adapted physical activity specialists who have expertise in the TGMD-2. Two advanced measurement theories, Generalizability-theory (G-theory) and many-facet Rasch model (MFRM), were applied in data analyses. There were relatively large variances attributed to rater effects on the scores of the TGMD-2 awarded to children with intellectual disabilities. The severity of each rater significantly differed across all subtests of the TGMD-2. There was a set of biased ratings interacted with measurement conditions of the TGMD-2.
Symeon P. Vlachopoulos and Maria A. Gigoudi
This article reports on the development and initial validation of the Amotivation Toward Exercise Scale (ATES), which reflects a taxonomy of older adults’ reasons to refrain from exercise. Drawing on work by Pelletier, Dion, Tuson, and Green-Demers (1999) and Legault, Green-Demers, and Pelletier (2006), these dimensions were the outcome beliefs, capacity beliefs, effort beliefs, and value amotivation beliefs toward exercise. The results supported a 4-factor correlated model that fit the data better than either a unidimensional model or a 4-factor uncorrelated model or a hierarchical model with strong internal reliability for all the subscales. Evidence also emerged for the discriminant validity of the subscale scores. Furthermore, the predictive validity of the subscale scores was supported, and satisfactory measurement invariance was demonstrated across the calibration and validation samples, supporting the generalizability of the scale’s measurement properties.
Roy J. Shephard
A quantitative hypothetico-deductive approach has continued to contribute greatly to advances in biological and medical science. Quantitative methods are adopted over other approaches primarily because they contribute the most new knowledge about biological processes. Nevertheless, investigators make many assumptions when testing a biological hypothesis quantitatively. These assumptions may become invalid unless experiments are designed with great care. Problems arise in relation to formulating appropriate hypotheses, using volunteer samples, controlling the experimental intervention and potentially interfering behaviors, reaching an acceptable level of proof, excluding alternative hypotheses, and generalizing findings beyond the immediate experimental sample. When biologists are aware of these issues, they can take appropriate countermeasures and reach valid conclusions. However, the issues become more critical and resolution is less clear-cut when the same methods are extended from biology to psychology and the social sciences, and from general to special populations. In such situations, case studies and single-subject designs may have continuing relevance.
Luke E. Kelly, James H. Rimmer and Richard A. Ness
The purpose of this investigation was to determine the percent body fat of 553 institutionalized mentally retarded adults, ages 18 to 40 yrs, from the Denton State School in Texas. The subjects included 343 males and 210 females. Their percent body fat was estimated with generalized regression equations. Body density for males was measured by the sum of three skinfolds, two girths, and age. Body density for females was measured by the sum of three skinfolds and age. The results from this study revealed that 45.2% of the males and 50.5% of the females were obese. The percent body fat of the female subjects was significantly greater than that of the male subjects. A post hoc analysis revealed that profoundly mentally retarded subjects had significantly lower percent body fat than those subjects functioning at the severe and mild levels. These findings indicate a serious need for more investigation of the caloric intake and expenditure of this population in an institutional environment.
Ron E. McBride
Six physical education specialists—two elementary, two junior high, and two high school (three males and three females)—were studied in an attempt to discern possible sex-role stereotyping in their classes. Data were triangulated from teacher observations, a sex-role inventory, and junior and senior high school student perceptions of teacher treatment in physical education classes. Results revealed that the female teachers used more managerial cues in their classes and called boys by name more frequently than did male teachers. Two male teachers were classified as being gender typed, but results from students of both sexes revealed no perceived differential treatment in class. From this teacher sample, the results suggest that perhaps the gymnasium is not quite the bastion of gender typing as is often assumed. Due to the small sample size, results were not generalized to a larger population and thus additional research is recommended.
Otávio Luis Piva da Cunha Furtado, Kelly Allums-Featherston, Lauren Joy Lieberman and Gustavo Luis Gutierrez
The authors conducted a systematic literature review on physical activity interventions for children and youth with visual impairment (VI). Five databases were searched to identify studies involving the population of interest and physical activity practices. After evaluating 2,495 records, the authors found 18 original full-text studies published in English they considered eligible. They identified 8 structured exercise-training studies that yielded overall positive effect on physical-fitness and motor-skill outcomes. Five leisure-time-physical-activity and 5 instructional-strategy interventions were also found with promising proposals to engage and instruct children and youth with VI to lead an active lifestyle. However, the current research on physical activity interventions for children and youth with VI is still limited by an absence of high-quality research designs, low sample sizes, use of nonvalidated outcome measures, and lack of generalizability, which need to be addressed in future studies.