1.
A comparison of two treatment protocols in the management of exercise-associated postural hypotension: a randomised clinical trial.
Anley, C, Noakes, T, Collins, M, Schwellnus, MP
British journal of sports medicine. 2011;(14):1113-8
Abstract
OBJECTIVE To investigate which of two commonly used treatment protocols for exercise-associated postural hypotension (EAPH) resulted in earlier discharge from the medical facility. METHODS This randomised clinical field trial was undertaken at two Ironman Triathlon competitions and one ultra-distance footrace. All collapsed athletes admitted to the medical facilities were considered for the trial. Following clinical assessment and special investigations to confirm the diagnosis of EAPH, 28 athletes were randomly assigned to an oral fluid and Trendelenburg position (OT=14) or an intravenous fluid (IV=14) treatment group. Following admission fluid intake was recorded, and all athletes were assessed clinically (blood pressure, heart rate, level of consciousness) every 15 min until discharge criteria were met. The main measure of outcome was the time to discharge (min). RESULTS On admission, subjects in the OT and IV groups were similar with respect to age, systolic blood pressure, heart rate and serum sodium concentration. There were no significant differences in heart rate, systolic and diastolic blood pressure between groups and over time until discharge. The fluid intake during the treatment period was significantly greater in the IV group (IV 1045 ± 185 ml, OT 204 ± 149 ml; p<0.001). The average time to discharge for the OT group (58 ± 23 min) was similar to that of the IV group (52.5 ± 18 min; p=0.47). CONCLUSION Endurance athletes with EAPH can be treated effectively using the Trendelenburg position and oral fluids and the administration of intravenous fluids does not reduce the time to discharge. The findings of this study support the hypothesis that EAPH is a result of venous pooling due to peripheral vasodilatation, rather than dehydration.
2.
Exploring the mechanisms of physical activity and dietary behavior change in the program x intervention for adolescents.
Lubans, DR, Morgan, PJ, Callister, R, Collins, CE, Plotnikoff, RC
The Journal of adolescent health : official publication of the Society for Adolescent Medicine. 2010;(1):83-91
Abstract
PURPOSE The objective of this investigation was to examine the mechanisms of physical activity and dietary behavior change in the Program X intervention. METHODS Program X involved a clustered randomized controlled design with six schools (N=124 participants, mean age=14.1+/-0.8 years) randomized to intervention or control conditions for the 6-month study period. Physical activity and fruit and vegetable consumption were assessed using pedometers and questionnaires, respectively. The theoretical framework of the intervention was assessed using structural equation modeling, mediation, and moderation analyses. RESULTS The model explained 56% of the variance in physical activity at 6-months, but did not represent a good fit to the data, chi(2)=87.43, df=19, p < .001. The model explaining fruit and vegetable consumption explained 31% of the variance and provided a good fit to the data, chi(2)=12.40, df=10, p=.259. None of the variables satisfied the criteria for mediation or moderation in the physical activity model, but gender moderated the effects of intervention on fruit and vegetable consumption. CONCLUSIONS None of the hypothesized mediators were responsible for behavior change in the Program X intervention. Future studies should address the limitations of existing psychosocial scales and continue to explore the mechanisms of behavior change using model testing, mediation, and moderation analyses.
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A mediation analysis of the ATHENA intervention for female athletes: prevention of athletic-enhancing substance use and unhealthy weight loss behaviors.
Ranby, KW, Aiken, LS, Mackinnon, DP, Elliot, DL, Moe, EL, McGinnis, W, Goldberg, L
Journal of pediatric psychology. 2009;(10):1069-83
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Abstract
OBJECTIVE To explain, through mediation analyses, the mechanisms by which ATHENA (Athletes Targeting Healthy Exercise and Nutrition Alternatives), a primary prevention and health promotion intervention designed to deter unhealthy body shaping behaviors among female high school athletes, produced immediate changes in intentions for unhealthy weight loss and steroid/creatine use, and to examine the link to long-term follow-up intentions and behaviors. METHODS In a randomized trial of 1668 athletes, intervention participants completed coach-led peer-facilitated sessions during their sport season. Participants provided pre-test, immediate post-test, and 9-month follow-up assessments. RESULTS ATHENA decreased intentions for steroid/creatine use and intentions for unhealthy weight loss behaviors at post-test. These effects were most strongly mediated by social norms and self-efficacy for healthy eating. Low post-test intentions were maintained 9 months later and predicted subsequent behavior. CONCLUSIONS ATHENA successfully modified mediators that in turn related to athletic-enhancing substance use and unhealthy weight loss practices. Mediation analyses aid in the understanding of health promotion interventions and inform program development.