The relationship between sport commitment and physical self-concept: Evidence for the self-enhancement hypothesis among adolescent females.

Perceptions of physical self-concept are critical to physical activity participation. In line with the reciprocal effects model of causal ordering (REM), higher perceptions of physical self-concept can function as a facilitator to physical activity, and can arise as a result of engaging in physical activity. While this relationship has been predominantly tested in physical activity contexts, directional tests between physical self-concept and sport specific outcomes are limited. The current study aimed to evaluate the generalizability of the REM to sport commitment and physical self-concept in youth athletes. Over 24 months, adolescent females (N = 215) completed self-report questionnaires at Time 1 (T1) and two years later (Time 2; T2). Using structural equation modeling, the reciprocal effects model demonstrated that the path leading from T1 physical self-concept to T2 sport commitment was significant (p = .02), whereas the path leading from T1 sport commitment to T2 physical self-concept was not significant (p = .23). The results suggest a unidirectional relationship and may underscore the importance of focusing on the physical self-concept in the development of strategies geared towards improving adolescent female's sport participation.

Changes in body-related self-conscious emotions over time among youth female athletes.

The current study explored change in body-related self-conscious emotions (e.g., shame, guilt, authentic pride, hubristic pride) over three years, and tested body surveillance, age, weight status, years in sport, and competitive status as baseline predictors of change. Adolescent females engaged in organized sport (N = 518 at baseline, Mage = 14.02, SD = 1.38 years) completed a self-report survey once a year for three years (n = 293 and n = 215 in Years 2 and 3, respectively). Based on the unconditional latent growth model, body-related shame and guilt increased over time, and authentic and hubristic pride decreased over time. There was substantial between-person variability in the intercepts for all emotions and slopes for shame, guilt, and hubristic pride. In the conditional parallel process latent growth model, body surveillance predicted shallower change in shame and guilt over time. Female athletes high in body surveillance also reported higher body-related shame and guilt and lower authentic and hubristic pride at baseline. These findings highlight the importance of studying changes in self-conscious emotions over time in sport, and demonstrate that body surveillance may be an important factor to explore in interventions early in development.

Haematopoiesis in molluscs: A review of haemocyte development and function in gastropods, cephalopods and bivalves.

Haematopoiesis is a process that is responsible for generating sufficient numbers of blood cells in the circulation and in tissues. It is central to maintenance of homeostasis within an animal, and is critical for defense against infection. While haematopoiesis is common to all animals possessing a circulatory system, the specific mechanisms and ultimate products of haematopoietic events vary greatly. Our understanding of this process in non-vertebrate organisms is primarily derived from those species that serve as developmental and immunological models, with sparse investigations having been carried out in other organisms spanning the metazoa. As research into the regulation of immune and blood cell development advances, we have begun to gain insight into haematopoietic events in a wider array of animals, including the molluscs. What began in the early 1900's as observational studies on the morphological characteristics of circulating immune cells has now advanced to mechanistic investigations of the cytokines, growth factors, receptors, signalling pathways, and patterns of gene expression that regulate molluscan haemocyte development. Emerging is a picture of an incredible diversity of developmental processes and outcomes that parallels the biological diversity observed within the different classes of the phylum Mollusca. However, our understanding of haematopoiesis in molluscs stems primarily from the three most-studied classes, the Gastropoda, Cephalopoda and Bivalvia. While these represent perhaps the molluscs of greatest economic and medical importance, the fact that our information is limited to only 3 of the 9 extant classes in the phylum highlights the need for further investigation in this area. In this review, we summarize the existing literature that defines haematopoiesis and its products in gastropods, cephalopods and bivalves.