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Physical activity has been shown to benefit cancer survivors' physical functioning, emotional wellbeing, and symptoms. Physical activity may be of particular benefit to survivors of endometrial cancer because they are more likely to be obese and sedentary than the general population, as these are risk factors for the disease, and thus experience a number of related co-morbid health problems. However, there is little research systematically studying mechanisms of physical activity adherence in cancer survivor populations. This paper describes the design of the Steps to Health study, which applies a Social Cognitive Theory-based model of endometrial cancer survivors' adoption and maintenance of exercise in the context of an intervention to increase walking or other moderate intensity cardiovascular activity. In Steps to Health we will test the influence of self-efficacy and outcome expectations on adherence to exercise recommendations, as well as studying the determinants of self-efficacy. Endometrial cancer survivors who are at least 6 months post-treatment are provided with an intervention involving print materials and telephone counseling, and complete assessments of fitness, activity, self-efficacy and outcome expectations, and determinants of self-efficacy every two months for a six month period. In addition to testing an innovative model, the Steps to Health study employs multiple assessment methods, including ecological momentary assessment, implicit tests of cognitive variables, and ambulatory monitoring of physical activity. The study results can be used to develop more effective interventions for increasing physical activity in sedentary cancer survivors by taking into account the full complement of sources of self-efficacy information and outcome expectations. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptPsychol Sport Exerc. Author manuscript; available in PMC 2012 January 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptPhysical activity benefits cancer survivors' physical and psychological functioning, as evidenced by the growing body of research on this topic (Ahmed, Thomas, Yee, & Schmitz, 2006;Basen-Engquist et al., 2006;Courneya, 2001Courneya, , 2003 Courneya & Christine M. Friedenreich, 1999;Courneya, Keats, & Turner, 2000;Courneya et al., 2007;Daley et al., 2007;Fairey, Courneya, Field, & Mackey, 2002;Friedenreich & Courneya, 1996;Galvao & Newton, 2005;Knols, Aaronson, Uebelhart, Fransen, & Aufdemkampe, 2005;Ohira, Schmitz, Ahmed, & Yee, 2006;Pinto & Maruyama, 1999;Schmitz et al., ...

For cancer survivors, who also often present with co-existing health conditions, exercise testing is often performed using submaximal protocols incorporating linear heart rate response for estimating cardiorespiratory capacity and assessing exercise tolerance. However, use of beta-blockers medications, during sub-maximal protocols based on linear HR response can be problematic. Rating of perceived exertion (RPE), which takes into account an individual’s overall perception of effort, can be used as a complementary tool that does not rely solely on heart rate response to increased workload. We compared heart rate response (VO2HR) and self-rating of perceived exertion (VO2RPE) in a graded submaximal exercise test (GXT) in 93 endometrial cancer survivors. Results of the GXT were stratified according to whether participants were taking beta-blocker (BB) medications or not (non-BB). Among non-BB participants, there was no difference between the mean VO2HR and the mean VO2RPE estimates of cardiorespiratory capacity (mlO2/ /kg/min), (20.4 and 19.3, respectively; p = 0.166). Among BB participants, the mean VO2HR approached significant difference than the mean VO2RPE, (21.7 mlO2/ /kg/min and 17.6 mlO2/ /kg/min, respectively; p = 0.087). Bland-Altman plots for both methods showed a proportional bias for the non-BB group; but not the BB group. Our results suggest that sub-maximal protocols based on Borg’s Rating of Perceived exertion (RPE) produce differing results from sub-maximal protocols based on HR response when applied to clinical population taking BB medications. Using RPE instead of HR for participants on BB medications, may be a better method for assessing exercise tolerance for estimating cardiorespiratory capacity in sub-maximal exercise testing.

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