Lipid peroxides can be both a product and an initiator of oxidant stress. Conceivably, exercise can either increase concentrations of lipid peroxides (by causing oxidant stress), or decrease them (by accelerating peroxide breakdown). The net effect could depend on exercise intensity and nutritional intake of antioxidants. The present study examined the response of serum lipid peroxides to the combination of moderate intensity, weight resistance exercise plus intake of soy protein, a source of antioxidant phytochemicals. Recreationally trained, young adult men (N = 18) consumed soy protein or antioxidant-poor whey protein for 4 weeks (40 g protein/d) before a session of moderate intensity, weight resistance exercise. In the soy group, exercise decreased values for serum lipid peroxides at 5 min, 3 h, and 24 h post-exercise. The whey group showed the depression only at 24 h. In both the soy and whey groups, a small rise was seen for interleukin-8, which is consistent with the idea that the exercise session induced a moderate muscle stress. In summary, a moderate intensity, weight resistance exercise session, despite inducing mild inflammation, depressed plasma serum peroxide values, especially when combined with 4 weeks of soy consumption.
Stephen Hill, Wesley Box and Robert A. DiSilvestro
Stephen Hills, Matthew Walker and Marlene Dixon
For sport for development practitioners, a theory of change document is a critical first step to map how program inputs yield the desired program outcomes. Yet, in our experience, this document is rarely created in practice. Accordingly, this study makes use of the case of an award-winning sport for development charity that expanded their operations from India to London to illustrate the pejorative implications resulting from failing to create a theory of change. A mixed-methods, quasi-experimental approach was utilized to understand program mechanisms, program processes, and how these influenced the aggregate participant experience. The quantitative analyses yielded no significant effects. Triangulating the qualitative data revealed that personal, social, health, and economic education was a competing product to the program. The limited effects are attributed to a failure to identify and attempt to assuage a local social problem. In addition, alignments with stakeholder expectations, program context, and legal requirements were also derailing. A discussion of the results, implications, and recommendations for establishing and implementing a theory of change are provided.
Stephen Hill-Haas, Greg Rowsell, Aaron Coutts and Brian Dawson
Stephen Samendinger, Christopher R. Hill, Teri J. Hepler and Deborah L. Feltz
Background: The positive role of self-efficacy in directing a wide range of health-related interventions has been well documented, including those targeting an increase in physical activity. However, rarely do researchers control the influence of past performance and past self-efficacy perception ratings when exploring the interaction of self-efficacy and performance, allowing for a refined understanding of this relationship and the unique contribution of each factor. Methods: A residualized past performance, residualized self-efficacy hierarchical regression model was used to examine the effect of prior past performance and pre-exercise self-efficacy on performance with a health-related task (12 aerobic exercise cycling sessions). Results: The previous day’s residualized performance was a significant predictor of performance, as was same-day residualized self-efficacy (P < .001). However, residualized self-efficacy became a stronger predictor over time. Conclusions: While maintaining a consistent level of moderate–vigorous physical activity over 12 exercise sessions, participants increased their ratings of task self-efficacy, explaining an increasing portion of the variance in the self-efficacy–performance relationship days 9 to 12.
Christopher R. Hill, Deborah L. Feltz, Stephen Samendinger and Karin A. Pfeiffer
Previous reviews have highlighted the importance of self-efficacy beliefs in maintaining adequate levels of childhood physical activity (PA), but variable findings with different age groups and measures of PA indicate the need to quantify the extant literature. The purpose of this meta-analysis was to estimate the relationship between adolescents’ barrier self-efficacy (BSE) and PA behavior using a random-effects model and to examine age and type of PA measurement as potential relationship moderators. A systematic online database review yielded 38 articles up to June 2018. A small to moderate correlation between BSE beliefs and PA was noted, although the variability was considerable. Age and measurement timing were not significant moderators, but the type of measurement was a significant relationship moderator. This meta-analysis emphasizes the importance of BSE as a psychosocial correlate to PA behavior in young people. There is a need for further BSE–PA research with attention to measurement technique and developmental differences.