Physical activity cost in children following an acquired brain injury - a comparative study

Background: Alterations in energy expenditure during activity post head injury has not been investigated due primarily to the difficulty of measurement. Objective: The aim of this study was to compare energy expenditure during activity and body composition of children following acquired brain injury (ABI) with data from a group of normal. controls. Design: Energy expenditure was measured using the Cosmed K4b(2) in a group of 15 children with ABI and a group of 67 normal children during rest and when walking and running. Mean number of steps taken per 3 min run was also recorded and body composition was measured. Results: The energy expended during walking was not significantly different between both groups. A significant difference was found between the two groups in the energy expended during running and also for the number of steps taken as children with ABI took significantly less steps than the normal controls during a 3 min run. Conclusions: Children with ABI exert more energy per activity than healthy controls when controlled for velocity or distance. However, they expend less energy to walk and run when they are free to choose their own desirable, comfortable pace than normal controls. (C) 2003 Elsevier Ltd. All rights reserved.

Associations of location and perceived environmental attributes with walking in neighborhoods

Purpose. Ecological models highlight the importance of environmental influences. We examined associations of coastal versus noncoastal location and perceived environmental attributes with neighborhood walking, total walking, and total activity. Methods. Telephone interviews with 800 faculty and general staff of an Australian university. Results. Men were significantly more likely to walk in their neighborhood if they lived in a coastal location (odds ratio [OR] = 1.66), and they highly rated environmental aesthetics (OR = 1.91), convenience of facilities (OR = 2.20), and access to facilities (OR = 1.98). For women, neighborhood walking was associated with high ratings of convenience (OR = 3.78) but was significantly less likely if they had high ratings for access (OR = 0.48). For total walking and total physical activity, few significant associations emerged. Conclusions. Environmental attributes were related to walking in the neighborhood but not to more general activity indices. Understanding gender-specific environmental correlates of physical activity should be a priority.

Axonal regeneration and lack of astrocytic gliosis in EphA4-deficient mice

Spinal cord injury usually results in permanent paralysis because of lack of regrowth of damaged neurons. Here we demonstrate that adult mice lacking EphA4 (-/-), a molecule essential for correct guidance of spinal cord axons during development, exhibit axonal regeneration and functional recovery after spinal cord hemisection. Anterograde and retrograde tracing showed that axons from multiple pathways, including corticospinal and rubrospinal tracts, crossed the lesion site. EphA4 -/- mice recovered stride length, the ability to walk on and climb a grid, and the ability to grasp with the affected hindpaw within 1-3 months of injury. EphA4 expression was upregulated on astrocytes at the lesion site in wild-type mice, whereas astrocytic gliosis and the glial scar were greatly reduced in lesioned EphA4-/- spinal cords. EphA4 -/- astrocytes failed to respond to the inflammatory cytokines, interferon-gamma or leukemia inhibitory factor, in vitro. Neurons grown on wild-type astrocytes extended shorter neurites than on EphA4 -/- astrocytes, but longer neurites when the astrocyte EphA4 was blocked by monomeric EphrinA5-Fc. Thus, EphA4 regulates two important features of spinal cord injury, axonal inhibition, and astrocytic gliosis.

Routine physiotherapy does not induce cardiorespiratory training effect post-stroke

Background and Purpose. Cardiorespiratory fitness is increasingly being recognized as an impairment requiring physiotherapy intervention after stroke. The present study seeks to investigate if routine physiotherapy treatment is capable of inducing a cardiorespiratory training effect and if stroke patients attending physiotherapy who are unable to walk experience less cardiorespiratory stress during physiotherapy when compared to those who are able to walk. Method. A descriptive, observational study, with heart rate monitoring and video-recording of physiotherapy rehabilitation, was conducted. Thirty consecutive stroke patients from a geriatric and rehabilitation unit of a tertiary metropolitan hospital, admitted for rehabilitation, and requiring physiotherapy were included in the study. The main measures of the study were duration (time) and intensity (percentage of heart rate reserve) of standing and walking activities during physiotherapy rehabilitation for non-walking and walking stroke patients. Results. Stroke patients spent an average of 21 minutes participating in standing and walking activities that were capable of inducing a cardiorespiratory training effect. Stroke patients who were able to walk spent longer in these activities during physiotherapy rehabilitation than non-walking stroke patients (p < 0.05). An average intensity of 24% heart rate reserve (HRR) during standing and walking activities was insufficient to result in a cardiorespiratory training effect, with a maximum of 35% achieved for the stroke patients able to walk and 30% for those unable to walk. Conclusions. Routine physiotherapy rehabilitation had insufficient duration and intensity to result in a cardiorespiratory training effect in our group of stroke patients. Copyright © 2006 John Wiley & Sons, Ltd.

Socio-demographic variations in walking for transport and for recreation or exercise among adult Australians

Background: Walking is integral to strategies to promote physical activity. We identified socio-demographic variations in walking for transport, and for recreation or exercise. Methods: Representative population data (n = 3392) from Australia were collected using computer assisted telephone interviewing, to examine adults’ participation in moderate- or brisk-paced walking for transport and walking for recreation or exercise; walking “sufficient” to meet the current public health guideline (> 150 min/wk); and, the contributions of total walking to meeting the guideline for total physical activity. Results: Rates of sufficient walking for transport (10% for men, 9% for women) were lower than those for walking for recreation or exercise (14% for both genders). Few socio-demographic differences emerged. Men over age 60 y were significantly less likely (OR = 0.40) to walk for transport; men age 45 to 59 y were more likely (OR = 1.56) to walk for recreation or exercise. Walking contributed more toward meeting the current public health guideline among women (15% to 21%) than among men (6% to 8%). Conclusions: There is potential for socially equitable increases in participation, through a focus on both walking for transport and on walking for recreation or exercise; attention to gender differences would be helpful.

Effect of Australia's walk to work day campaign on adults' active commuting and physical activity behavior

Purpose. To determine whether Australia's Walk to Work Day media campaign resulted in behavioural change among targeted groups. Methods. Pre- and postcampaign telephone surveys of a cohort of adults aged 18 to 65 years (n = 1100, 55% response rate) were randomly sampled from Australian major melropolitan areas. Tests for dependent samples were applied (McNemax chi(2) or paired t-test). Results. Among participants who did not usually actively commute to work was a significant decrease in car only use an increase in walking combined with public transport. Among those who were employed was a significant increase in total time walking (+16 min/wk; t [780] = 2.04, p < .05) and in other moderate physical activity (+120 min/wk; t [1087] = 4.76, p < .005), resulting in a significant decrease in the proportion who were inactive (chi(2) (1) = 6.1, p < .05). Conclusion. Although nonexperimental, the Walk to Work Day initiative elicited short-term changes in targeted behaviors among target groups. Reinforcement by integrating worksite health promotion strategies may be required for sustained effects.

Scaling and non-scaling of muscle activity, kinematics, and dynamics in sit-ups with different degrees of difficulty

The purpose of this study was to investigate how the CNS adjusts motor patterns for variants of a complex axial movement-the situp. Adjustments were induced by changing the support surface contact and mass distribution of the body. Healthy adults performed straight-legged sit-ups, 3 s in duration, with support added to or removed from the lumbar trunk, or with mass added to the head or to the legs. Each of these interventions either increased or decreased the difficulty of the task. The study addressed the extent to which changes in sit-up difficulty are compensated by scaling of muscle activity, kinematics, and dynamics versus the extent to which they are compensated by changing discretely the motor pattern. The analysis of muscle activity, kinematics, and dynamics focused on the first 30-40% of the sit-up-the trunk flexion phase-since this is the most critical part of the movement. Our results demonstrate that, in some respects, sit-up kinematics and dynamics scaled with difficulty, but in other respects, they did not. Muscle activity also scaled, in many respects, but in more difficult sit-ups, abdominal flexor activity decreased instead of increased. Non-scaling changes in these parameters suggest that complex movements, such as the sit-up, may require discrete changes in motor pattern in order to deal with large loads, which challenge the available leverage. (C) 2005 Elsevier Ltd. All rights reserved.

The emergence of order in random walk resource discovery protocols

While others have attempted to determine, by way of mathematical formulae, optimal resource duplication strategies for random walk protocols, this paper is concerned with studying the emergent effects of dynamic resource propagation and replication. In particular, we show, via modelling and experimentation, that under any given decay (purge) rate the number of nodes that have knowledge of particular resource converges to a fixed point or a limit cycle. We also show that even for high rates of decay - that is, when few nodes have knowledge of a particular resource - the number of hops required to find that resource is small.

Using Q-methodology to study the metaphors of consumption for mobile phone users

Even before business has really come to grips with the intricacies of incorporating emarketing and e-commerce into their organisational strategies, they are now being encouraged to make significant investments in developing capabilities for mobile phone marketing. Fuelled once again by huge profit predictions reminiscent of the mid-1990s when speaking of e-commerce (Anckar and D’Incau 2002) marketers are tapping into this mobility. So, instead of having to drive consumers to web sites through the ‘sit and search’ context, marketers are now exploring ways to develop strategies to deliver relevant and timely information in a ‘roam and receive’ context directly to their potential customers anywhere, anytime, any place (Mort and Drennan 2002).

Not if but when: Out-group reactions to the timing of disclosure of an individual's same-sex attractions

One factor that research suggests impedes positive contact between outgroup members is the experience of anxiety that can occur when anticipating negative consequences of such interactions. Research examining attitudes and behaviour towards same-sex attracted individuals indicates that this intergroup anxiety is particularly evident when the anticipated interaction involves members of the same gender. The current studies investigate the effect of timing of disclosure of a person’s same-sex attractions in an effort to identify a means of reducing this anxiety. Study 1 uses a hypothetical scenario to gain insight into participants’ stated preferences for early or delayed knowledge of a person’s sexual orientation. Results reveal an association between experiencing close contact with gay individuals of the same gender in real life (but not opposite gender), and a preference for early disclosure. Results from an experimental study concur with these findings. After a face-to-face interaction task with a confederate of the same gender, participants sit further from the confederate for the late disclosure condition when compared with the early disclosure and no disclosure control. Future studies investigating the interaction between timing of disclosure of same-sex attractions and the intimacy of disclosure (casual vs. intimate), are discussed.