Analysis of mediation and reciprocal effects of changes in weight, self-esteem, and exercise in a behavioral weight loss treatment

Improving the treatment of obesity remains a critical challenge. Several health behaviour change models, often based on a social-cognitive framework, have been used to design weight management interventions (Baranowski et al., 2003). However, most interventions have only produced modest weight reductions (Wadden et al., 2002) and socialcognitive variables have shown limited power to predict weight outcomes (Palmeira et al., 2007). Other predictors, and possibl alte nati e e planatory models, are needed to better understand the mechanisms by which weight loss and other obesity treatment-outcomes are brought about (Baranowski, 2006). Self-esteem is one of these possible mechanisms, because is commonly reported to change during the treatment, although these changes are not necessarily associated with weight loss (Blaine et al., 2007; Maciejewski et al., 2005). This possibility should be more evident if the program integrates regular exercise, as it promotes improvements in subjective well-being (Biddle & Mutrie, 2001), with possible influences on long-term behavioral adherence (e.g. diet, exercise). Following the reciprocal effects model tenets (Marsh & Craven, 2006), we expect that the influences between changes in weight, selfesteem and exercise to be reciprocal and might present one of the mechanisms by which obesity treatments can be improved.

Reported Use of Anabolic Steroids and Ergogenic Substances in Gym/Health Club Settings: Associations with Psychosocial and Exercise Behavior Factors

The industry of ergogenic supplements is increasing rapidly (Cole et al., 2003). Supplements may constitute an important aid for some vigourous exercise routines, but they may also be used as a hypothetical mean to achieve increases in muscular mass. This supposed effect of suplements can lead to its use by individuals who have high levels of drive for muscularity, a condition that is known to be associated with muscular dismorphy (or as it has been called recently vigorexia, Pope et al., 1997). Another psychological factor which can influence supplement consumption is exercise dependence, a borderline problem, as most studies present a prevalence of less than 10% in regular exercisers (Palmeira & Matos, 2006). Symptoms like tolerance or continuity could lead to the use of ergogenic aids to maintain the exercise levels. Also of interest for the understanding of the use of suplements are exercise frequency, volume and intensity, which could explain the ratesof consumption on a more physicological level.

Confirmatory Factor Analysis of the Behavioural Regulation in Exercise Questionnaire – Portuguese Version

Exercise constitutes one of the pillars of a healthy lifestyle (USDHHS, 1996). Paradoxically, more than 40% of Europeans are sedentary (Eurobarometer 213, 2004), although some interventions, at both community and individual levels, have been established to improve this situation. Some of these interventions are based on Self-Determination Theory (SDT: Deci & Ryan, 1985), which state that more internalized types of behaviour regulation lead to feelings of selfdetermination in one’s chosen activities and, consequently, to greater likelihood of behavioural adherence. Today, SDT is one of the most popular approaches to the study of exercise, thus the cross-cultural validation of instruments that can measure its constructs is a necessary step to further advance in the study of exercise motivation.