Association between socio-economic status and physical activity is mediated by social support in Brazilian students.

This study evaluated whether the relationship between socioeconomic status (SES) and moderate-to-vigorous physical activity (MVPA) is mediated by social support of peers and parents. A cross-sectional study included students (n = 1182) aged 11 to 18 years who were recruited in 2014 from public schools in Fortaleza, Brazil. Participants completed a questionnaire to assess all variables. Mediation analyses were performed to determine the role of parental support and peer support on the relationship between SES and MVPA. Also, moderated-mediation analyses with estimating of conditional indirect effects were performed in order to identify whether gender is a moderator of the mediating effect. A positive and significant association between SES and MVPA was found among Brazilian students, and social support of parents and peers were significant mediators of this relationship. Conditional indirect effects showed that both parental and peer support had a significant indirect effect among boys; only parental support had a significant indirect effect among girls. These results suggest that improving social support can help reduce the impact of SES on physical activity among Brazilian adolescents.

Accuracy of the vivofit activity tracker.

The purpose of this study was to examine the accuracy of the vivofit activity tracker in assessing energy expenditure and step count. Thirteen participants wore the vivofit activity tracker for five days. Participants were required to independently perform 1 h of self-selected activity each day of the study. On day four, participants came to the lab to undergo BMR and a treadmill-walking task (TWT). On day five, participants completed 1 h of office-type activities. BMR values estimated by the vivofit were not significantly different from the values measured through indirect calorimetry (IC). The vivofit significantly underestimated EE for treadmill walking, but responded to the differences in the inclination. Vivofit underestimated step count for level walking but provided an accurate estimate for incline walking. There was a strong correlation between EE and the exercise intensity. The vivofit activity tracker is on par with similar devices and can be used to track physical activity.

Impact of Nintendo Wii Games on Physical Literacy in Children: Motor Skills, Physical Fitness, Activity Behaviors, and Knowledge.

Physical literacy is the degree of fitness, behaviors, knowledge, and fundamental movement skills (agility, balance, and coordination) a child has to confidently participate in physical activity. Active video games (AVG), like the Nintendo Wii, have emerged as alternatives to traditional physical activity by providing a non-threatening environment to develop physical literacy. This study examined the impact of AVGs on children's (age 6⁻12, N = 15) physical literacy. For six weeks children played one of four pre-selected AVGs (minimum 20 min, twice per week). Pre and post measures of motivation, enjoyment, and physical literacy were completed. Results indicated a near significant improvement in aiming and catching (p = 0.06). Manual dexterity significantly improved in males (p = 0.001), and females felt significantly less pressured to engage in PA (p = 0.008). Overall, there appears to be some positive impact of an AVG intervention on components of physical literacy.

Gender-specific movement strategies using a computer-pointing task.

Females typically demonstrate a movement time advantage for tasks requiring high levels of manual dexterity, whereas males are notably better at targeting activities. According to D. Kimura (2000), the hunter-gatherer hypothesis primarily accounts for those performance advantages; that dichotomy fails, however, when one makes movement outcome predictions for tasks that are not clearly fine-motor or interceptive in nature. Investigators have recently proposed that time constraints (M. Peters, 2005) and gender-specific response style differences (M. Peters & P. Campagnaro, 1996; L. E. Rohr, 2006) affect motor performance. Here, the author used a computer-pointing task measuring both movement error and movement time in 16 participants to further investigate response style differences. Kinematic and linear regression analyses between resultant error and both movement time and task difficulty reinforced the notion that gender-specific movement biases emphasize speed and accuracy, respectively, for men and women.

Reaching patterns across working space: the effects of handedness, task demands, and comfort levels.

Two experiments are reported which examine skill demands, location, and perceived comfort levels for a preferential reaching test with left- and right-handed participants. In Experiment 1, the effect of task demands was examined by having participants perform tasks of varying difficulty with tools (Lift, Pantomime, and Use) that were placed in an array in working space. Preferred hand reaches predominated at the midline and ipsilateral positions, and decreased significantly for contralateral positions, where the frequency of preferred hand reaches increased with task difficulty. In Experiment 2 we developed a new measure (the Comfort Rating Scale) to rate the subjective feeling of comfort for reaching movements. Using the same array of tools and tasks, participants were instructed which hand to use to perform reaching movements, and then rated how the movement felt. The preferred hand was always rated as being comfortable, whereas the non-preferred hand was sensitive to the effects of task demands and tool position. The ratings showed that it was the level of comfort with the non-preferred hand, rather than with the preferred hand, that contributed to the patterns seen on the first study. The Comfort Rating Scale provides new insight into the distribution of reaching movements within working space.

Upper and lower limb reciprocal tapping: evidence for gender biases.

According to D. Kimura's (2000) interpretation of the hunter-gatherer hypothesis, men are better at targeting tasks and women are better at fine-motor tasks because of their evolutionary experiences. The author applied that hypothesis to a lower limb pointing task, a task uninfluenced by hunting and gathering experience throughout history. Participants (39 women, 35 men) completed the P. M. Fitts (1954) task by using both their dominant right hand and foot. Results suggested that for both the upper and lower limbs, men move faster, particularly for the more difficult tasks. The hunter-gatherer hypothesis does not predict those data; rather, linear regression data suggest that gender differences in movement strategies affect motor performance. The author proposes that men and women preferentially adopt distinct strategies emphasizing speed for men and accuracy for women.

Using hand performance measures to predict handedness.

Handedness is defined by the individual's preference to use one hand predominately for unimanual tasks and the ability to perform these tasks more efficiently with one hand (Corey, Hurley, & Foundas, 2001). It is important to use performance variables to measure handedness because they are more objective than traditional hand preference questionnaires (Bryden, Pryde, & Roy, 2000a). The current study develops a predictive model of handedness as measured by the Waterloo Handedness Questionnaire (WHQ) using several performance indicators of handedness. A total of 120 individuals (60 right-handers and 60 left-handers) were asked to complete four performance-based tasks: the Grooved Pegboard (GP), the Annett pegboard (AP), finger tapping (FT), and grip strength (GS) as well as an observational measure of preference, the Wathand Box Test (WBT). Backward linear regression analysis showed that the Wathand Box measure and the laterality quotients for several performance measures (GP place, AP, and FT) combined to act as the most accurate predictors of hand preference. The predictive model of handedness developed is as follows: WHQ = -2.760- - 0.667(GP place) + 0.809(FT) + 0.234(WBT) - 0.748(AP) with an explained variance of 0.836. These results illustrate, as Corey et al. (2001) suggested, that the best predictive model of handedness combines preference measures and several performance measures that tap into different elements of motor performance. By developing this model, it is possible to get an accurate measure of handedness using objective measures.

The performance of left-handed participants on a preferential reaching test.

Previous research in our laboratory has examined the distribution of preferred hand (PH) reaches in working space with right-handed participants. In one study, we examined the effects of tool position and task demands on the frequency of PH reaches with right-handers (Mamolo, Roy, Bryden, & Rohr, 2004). We found that PH reaches were at a maximum within ipsilateral space, and predominated within contralateral space. This was mediated by the task demands, as shown by an increased frequency of PH reaches for the more skill demanding tasks. In the current study, we tested left-handed participants on the same procedure. Five different tools were placed in an array in front of the participant, who was required to reach for, and perform one of three tasks with the tool: Lift the tool; lift and Pantomime its use; or lift and Use the tool on its corresponding object. The results showed that PH reaches were at a maximum within ipsilateral space for all three tasks. Significantly fewer PH reaches were made for tools in contralateral space. In particular, almost no PH reaches were made for the Lift task at the most extreme contralateral position. This indicates the willingness of left-handers to use their non-preferred (i.e., right) hand. One possible explanation supported by these results is that left-handers have adapted to an environment designed for right-handers.

Preference and performance measures of handedness.

Handedness cannot be predicted using a single performance measure, and preference measures of handedness are unreliable because of their subjectivity. This report was designed to examine the relationship between hand performance and hand preference using six different measures: the Waterloo Handedness Questionnaire (a measure of hand preference), the Wathand Box (a performance-based indicator of hand preference), two pegboard tasks, finger tapping, and grip strength and to determine the most accurate performance-based predictor of hand preference as measured by the Waterloo Handedness Questionnaire. Multiple linear regression analysis showed that together, the Wathand Box score and the lateralized place phase of the grooved pegboard task were the most accurate predictors of hand preference.

The effects of skill demands and object position on the distribution of preferred hand reaches.

Performance-based measures of hand preference have been developed as an objective method of examining handedness. Previous research using this method showed that both skill demands and the position of the object in working space affect preferential hand reaching. Specifically, preferred hand reaches predominated in left hemispace, in spite of the biomechanical inefficiency involved in reaching across the body midline. This was mediated by the skill demands, with a higher frequency of preferred hand reaches for tasks requiring more skill. To further examine this issue, we increased the task skill demands. Twenty-two right-handed adults reached for five tools located in an array of five positions in front of them. Participants were required to pick up the tool, pick up and demonstrate how to use it, or pick up and actually use the tool on the materials provided. The results showed that the frequency of right hand reaches was greatest for the tool use condition. This effect was mediated by the position of the object in hemispace, with more right hand reaches occurring for the Use task in left hemispace than the other tasks, in support of our previous work.

Effect of movement termination in single- and dual-phase pointing tasks.

Two experiments are reported that focus on manipulating both the context and the spatial precision of a computer-pointing task. Single goal-directed actions are compared to dual-phase tasks, where participants are required to sequentially attain two goal locations. Results support the idea that for movements in series, movement planning, and online feedback, control can occur simultaneously. Additionally, for single-phase tasks and the final phase of dual-phase tasks, the termination requirement influences the temporal components of the movement. The effects of termination and movement context appear to hold regardless of the spatial precision of the task. This suggests that the effects of spatial precision and movement termination are independent, although both have an impact on the deceleration time for goal-directed movements.