The role of implicit and explicit components of exerciser self-schema in the prediction of exercise behaviour

ObjectivesThis study investigated implicit and explicit components of exerciser self-schema and their role in the prediction of exercise behaviour. In addition, the effect of implicit and explicit exerciser self-schema on intention to exercise was examined. Moderation and mediation effects involving exerciser self-schema, in both its implicit and explicit forms, were investigated.MethodMembers of fitness centres and other regular exercisers (N = 98, n_males = 37, n_females = 65) completed a written questionnaire to measure explicit exerciser self-schema and exercise intentions. An exercise Implicit Association Test (IAT) was also administered to measure implicit exerciser self-schema. Actual exercise occurrence was measured one week and two weeks following the initial testing phase.ResultsCorrelations indicated that implicit and explicit components of exerciser self-schema were related but distinct constructs. Hierarchical regression analysis revealed that high levels of both implicit and explicit exerciser self-schema improved absolute levels of exercise behaviour. Regression analyses examining the possibility that self-schema moderated the intention–behaviour relationship were not significant for implicit or explicit forms of self-schema. Forced entry regression analyses provided evidence for explicit exerciser self-schema being mediated by intention in its relationship with behaviour.ConclusionsIt is beneficial to consider both implicit and explicit exerciser self-schema when attempting to understand and predict exercise behaviour. Both implicit and explicit exercise self-schema have a direct effect on behaviour, although explicit self-schema also indirectly influences behaviour via intention to exercise.     

Basic dimensions of work design: new inputs to functional flexibility

Although a lot of research has been developed during the last century in the field of human work design, the results seem to be unsatisfactory. Nowadays, there is renewed interest in this field but it is not producing any new results. This is the main reason why, in our investigation, we have tried to determine the real variables that truly affect the human work design. We have carried out two empirical researches involving 660 and 310 companies, obtaining from both exactly the same results, four factors that confirm the conclusions reached in previous research: demand-adaptation, flexibility-polyvalence, improvement-autonomy and conciliation-participation. We can add that these factors are independent from the environment and the type of technology used by the companies, which does not occur if the size of the enterprise is taken into account.     

Spanish adaptation of the Stepparent Role Strain Index

Stepparent role strain refers to the fragile position of these family members in stepfamilies due to the lack of clear social expectations about their roles. This ambiguity facilitates family conflict and a lack of stepparents' integration into the family system. The aim of this paper is to adapt a pioneer measure of stepparent role strain--the Stepparent Role Strain Index of Whitsett and Land (1992)--in a Spanish sample and to analyze its construct validity. The final instrument is made up of 26 items which have good internal consistency (alpha = .89) and an underlying six-factor structure, explaining 64.50% of the total variance.     

Children's recall and source monitoring of a repeated event using a timeline as an interview aid

Investigators sometimes use timelines (visual depictions of time) to help children identify temporal information from experienced events or details from a particular instance of a repeated event. However, little is actually known about the efficacy of this visual aid on children's memories. Six‐ to 9‐year‐olds participated in four occurrences of a repeated event and were later interviewed with or without the use of a timeline. Children in the timeline condition were less accurate and made more source‐monitoring errors than those in the control condition. For items that appeared consistently throughout the events, a suggestibility effect was more evident for older children who used the timeline than those who did not. Overall, there was no clear evidence in support of the visual aid. Despite its popularity, our findings suggest that timelines should be further examined to establish whether, and under what circumstances, they might be used in investigative contexts.     

预见性的本体论指归

囿于认识论或价值论范围,把有关预见性的一切解释置于本体论解释的视野之外,预见性的本体论根据之追究就会被无端地“搁置”起来,从而处在被“荒漠化”的境地,本体论意义之显现也就会被严实地“遮蔽”起来,即使偶有论及也只处在被“边缘化”的地带。本文由自我认识的诠解引发关于自我认识的预见性研究的本体论和方法论意义,进而集中解说自我认识何以具有预见性,自我认识的预见性有什么特点和表现形式,其存在变化是否具有客观基础暨本体论指归。     

The metabolic and cognitive energy costs of stabilising a high-energy interlimb coordination task

Kinematic (relative phase error), metabolic (oxygen consumption, heart rate) and attentional (baseline and cycling reaction times) variables were measured while participants practised a high energy-demanding, intrinsically unstable 90 degrees relative phase coordination pattern on independent bicycle ergometers. The variables were found to be strongly inter-correlated, suggesting a link between emerging performance stability with practice and minimal metabolic and attentional cost. The effects of practice of 90 degrees relative phase coordination on the performance of in-phase (0 degrees-phase) and antiphase (180 degrees-phase) coordination were investigated by measuring the relative phase attractor layouts and recording the metabolic and attentional cost of the three coordination patterns before and after practice. The attentional variables did not differ significantly between coordination patterns and did not change with practice. Before practice, the coordination performance was most accurate and stable for in-phase cycling, with antiphase next and 90 degrees-phase the poorest. However, metabolic cost was lower for antiphase than either in-phase or 90 degrees-phase cycling, and the pre-practice attractor layout deviated from that predicted on the basis of dynamic stability as an attractor state, revealing an attraction to antiphase cycling. After practice of 90 degrees-phase cycling, in-phase cycling remained the most accurate and stable, with 90 degrees-phase next and antiphase the poorest, but antiphase retained the lowest metabolic energy cost. The attractor layout had changed, with new attractors formed at the practised 90 degrees-phase pattern and its symmetrical partner of 270 degrees-phase. Considering both the pre- and post-practice results, attractors were formed at either a low metabolic energy cost but less stable (antiphase) pattern or at a more stable but higher metabolic energy cost (90 degrees-phase) pattern, but in neither case at the most stable and accurate (in-phase) pattern. The results suggest that energetic factors affect coordination dynamics and that coordination modes lower in metabolic energy expenditure may compete with dynamically stable modes.     

Practice effects on coordination and control,metabolic energy expenditure,and muscle activation

One defining characteristic of skilled motor performance is the ability to complete the task with minimum energy expenditure. This experiment was designed to examine practice effects on coordination and control, metabolic energy expenditure, and muscle activation. Participants rowed an ergometer at 100 W for ten 16-min sessions. Oxygen consumption and perceived exertion (central and peripheral) declined significantly with practice and movement economy improved (reliably) by 9%. There was an associated but non-significant reduction in heart rate. Stroke rate decreased significantly. Peak forces applied to the ergometer handle were significantly less variable following practice and increased stability of the post-practice movement pattern was also revealed in more tightly clustered plots of hip velocity against horizontal displacement. Over practice trials muscle activation decreased, as revealed in integrated EMG data from the vastus lateralis and biceps brachii, and coherence analysis revealed the muscle activation patterns became more tightly coordinated. The results showed that practice reduced the metabolic energy cost of performance and practice-related refinements to coordination and control were also associated with significant reductions in muscle activation.     

Adapting to Context in Community-Based Participatory Research: “Participatory Starting Points” in a Chinese Immigrant Worker Community

Community-based participatory research (CBPR) is increasingly being used to better understand and improve the health of diverse communities. A key strength of this research orientation is its adaptability to community contexts and characteristics. To date, however, few studies explicitly discuss adaptations made to CBPR principles and processes in response to community context and partners’ needs. Using data from our CBPR study, the San Francisco Chinatown Restaurant Worker Health and Safety Project, and drawing from literature on immigrant political incorporation, we examine the links between the contexts of the Chinese immigrant worker community, adaptations made by our collaborative, and study outcomes. In particular, we explore the concepts of contexts of reception and participatory starting points, which may be especially relevant for partnerships with immigrant communities whose members have historically had lower rates of civic and political participation in the US. We discuss contextual findings such as worker partner accounts of language barriers, economic and social marginalization, and civic skills and participation, as well as subsequent adaptations made by the partnership. We also describe the relative effectiveness of these adaptations in yielding equitable participation and building partners’ capacity. We conclude by sharing lessons learned and their implications for CBPR and partnerships with immigrant communities more broadly.     

Experimental evidence of relaxation arising from the motion of geometrical kinks on screw dislocations in iron

Abstract

Internal friction measurements with a superimposed bias stress have provided evidence for geometrical kink migration on screw dislocations in iron. This intrinsic process causes a relaxation phenomenon in internal friction which has been identified with the occurrence of a subpeak (below 20 K) of the α-peak. The effect of different bias stress has allowed us to evaluate the kink migration energy, E ^m _k ? 0·001eV.