In the current investigation, a quasi-experimental design was used. The outcomes of weight loss (as evaluated by BMI), PA involvement, and motivation regulation for exercise behaviors were measured over three time periods. Participants self-selected their condition (intervention or control). The changes in the outcome variables from baseline that occurred right after the intervention were recorded in the data collection at Time 1. The durability of any changes in the outcome variables from baseline to Time 1 was assessed by Time 2 data collection. Based on a power analysis with a fixed power (), five variables (k = 5), and a modest effect size (r = 0.25), a target sample size (n = 91) was determined for each cohort.
= 0.80) for a specified alpha level (p .05) in accordance with Cohen's (1992) suggestions. At least 182 people would be enrolled at the time the trial was finished, assuming that recruiting was effective during the whole study.
Participants (N = 88) were selected from The Club at White Oaks in Niagara-on-the-Lake, Ontario, after receiving approval from the Brock University Research Ethics Board (File: 11-096; see Appendix A). The participants who had signed up for the club's yearly 12 week weight loss challenge were used to draw participants in the weight loss intervention (n = 42) via email and personal contact. The Challenge started on January 9 and ended on March 31. Recruitment for the "do as you do" control condition (n = 46) took place through club poster advertisements (see Appendix B). Each participant received a letter of information (see Appendix C) and an informed consent form after initial contact (see Appendix D). The informed consent explicitly noted that challenge participants could leave the current experiment at any time.
without having an impact on their commitment to the challenge.
Each participant filled out a Physical Activity Readiness Questionnaire after receiving consent (PAR-Q; see Appendix E). Two participants were asked to obtain a doctor's approval before participating in the study after answering "yes" to one of the seven questions. Participants were asked whether they preferred a male or female Canadian Society of Exercise Physiology (CSEP) assessor at the beginning of the data collection session. The chosen CSEP assessor conducted the participants' body composition and anthropometric measurements in a confidential assessment office within the facility. After that, participants were instructed to complete a questionnaire package (see Appendix F), which included questions about demographic and lifestyle details, a self-reported PA measure, and a motivational rules for exercise measure. The questionnaire packet took about 20 to 30 minutes to complete, and the lead investigator was on hand to address any issues that might have come up throughout the assessment session.
Measures
facts on lifestyle and demographics. We gathered pertinent demographic, medical, and weight-control information. The following information was collected: gender, marital status, education, employment status, ethnicity, and four current medical conditions. To evaluate the participants' history of weight control, five items were created (example: "Have you tried to lose weight in the past 12 months?"). Finally, participants took a single-item test to evaluate the Transtheoretical Model's stages of transformation for PA (DiClemente & Prochaska, 1998).
Body weight and height. Seca scales calibrated to standards were used to measure each participant's weight (kg), and a Gulick tape was used to measure their height (m).
mounted measurement on a wall. Then, each participant's BMI was determined using the following formula:
BMI is calculated as follows: (kg/m2) (CSEP, 2010).
Exercise as reported by the individual. Self-reported PA involvement was assessed using a modified version of the Godin Leisure Time Exercise Questionnaire (LTEQ; Godin & Shepard, 1985). For the purposes of this study, the LTEQ was changed to measure exercise time in 10-minute intervals rather than the original 15-minute intervals. This change was made to better conform to the most recent Canadian PA recommendations. Support for the construct validity of test results has been discovered in other investigations utilizing a similar version of the LTEQ (Trinh, Plotnikoff, Rhodes, North, & Courneya, 2011; Karvinen, Raedeke, Arastu, & Allison, 2011). The modified LTEQ (Godin & Shepard, 1985) is a three-item self-report LTPA measure that evaluates the frequency and duration of mild (easy walking, yoga), moderate (regular cycling, easy swimming), and vigorous (heavy lifting, aerobics) PA performed in bouts of 10 minutes or longer throughout an average week. In order to be consistent with the recommended intensities in Canada's PA guidelines, scores for the moderate and vigorous PA were used in the current study. The total MVPA was determined by dividing each value by its
With the following formula, determine the energy expenditure in matching MET: [(Moderate
5) + (Difficult 9)] (1985, Godin & Shepard).
Validity and dependability of the LTEQ. Numerous research have validated the LTEQ scores, which have been found to compare favorably with other self-report measures for PA and to correlate with physical fitness markers that are expected as a result of more regular exercise involvement (Trinh et al., 2011; Karvinen et al., 2011). (Jacobs, Ainsworth, Hartman, & Leon, 1993). The LTEQ is simple to use and provides ratings between
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Using numerous test administrations, this device appears to be reliable over time (Rhodes, Courneya, Blanchard, & Plotnikoff, 2007).
Exercise Motivational Regulation. A 23-item self-report tool called the Behavioural Regulation in Exercise Questionnaire (BREQ-2R; Markland & Tobin, 2004; Wilson, Rodgers, Loitz, & Scime, 2006) was created to evaluate motivational regulations in line with SDT (Deci & Ryan, 2002). Six subscales evaluating amotivation, external, introjected, identifiable, integrated, and intrinsic regulations are included in the BREQ-2R. They range from 0 (not true for me) to 4 on a 5-point scale (very true for me). The BREQ-2R was transformed into a 19-item instrument for the current study by removing the motivation-related items. Each item with the stem "Why do you exercise?" was followed by a response prompt for participants. Examples of such statements were "I exercise because others tell me to" (extrinsic regulation), "I feel like a failure when I haven't worked out in a while" (introjected regulation), "I get restless if I don't exercise regularly" (identified regulation), "I exercise because it is consistent with my values" (integrated regulation), or "I enjoy my exercise sessions" (intrinsic motivation).
A modified version of the BREQ-2 is the BREQ-2R. Scores from the BREQ-2 have shown structural validity and construct validity (Markland & Tobin, 2004). (Wilson & Rodgers, 2004). The "integrated" motivational regulation is measured by the BREQ-2R. (assimilation of identified values and goals with other aspects of the self). The addition of the integrated subscale does not seem to have an impact on the reliability of BREQ-2 responses, and a community sample of exercisers has shown that test results are construct valid (Wilson et al., 2006). Additionally, the integrated regulation subscale exhibits internal consistency, reliability, and temporal stability, enabling the evaluation of integrated regulation in an exercise environment (Duncan, Hall, Wilson, &
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Wilson et al., 2006; Wilson & Jenny, 2010).
Participants were booked for their Time 1 session, which took place 12 weeks after the baseline measurements were finished. They were also informed that they would get a phone call one week before the appointment to remind them to show up. After the baseline data collection was complete, the participants in the intervention condition were matched with a Precision Nutrition coach and Personal Trainer to begin their weekly coaching sessions. They were also given the necessary information to access the additional educational programming that was made available to them as part of the weight loss challenge. The control group was told to "do as they do" for the following 12 weeks.
The Intervention Condition for the Weight Loss Challenge
The Club at White Oaks offered a yearly weight loss challenge to the general membership that included pre- and post-challenge body composition and anthropometric measurements, weekly nutrition and exercise coaching sessions4, provided by a Can-Fit-Pro (CFP) certified Personal Trainer and Precision Nutrition (PN) coach, and bi-weekly educational programming5 that alternated between healthy cooking demonstrations led by a certified chef and educational seminars led by a registered dietitian. The weight loss challenge has a three-month price tag of $170 each month. At a recognition event conducted a week after the Challenge's conclusion, the top three finishers (those who lost the most weight) of the intervention condition received monetary rewards3. For more information on the intervention, refer to the research flowchart in Appendix G.
The Control Condition: The Weight Loss Challenge
The general membership of the same club's non-weight loss participants served as the pool from which the participants in the control condition were drawn.
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challenge. Participants in the control condition were told to "do as they do" throughout the investigation. While not having access to the instructional programs provided as part of the weight loss challenge, some control condition participants may have continued to use the personal training services provided at the club.
The same CSEP assessor examined participants' weight (kg) and height (m) at the conclusion of the 12-week weight reduction challenge during the data collecting period post-intervention (i.e., Time 1). Each participant likewise filled out the identical questionnaire package, minus the sections on demographics and way of life. Each participant was given a time slot for their Time 2 visit, which was held 14 weeks after the Time 1 data collection, and was informed that, once more, telephone reminders would be given one week in advance. After that, participants in both groups were told to "do as they do" for the following 14 weeks.
Analysis of Data
The process of data analysis was sequential. The data was initially checked for outliers and missing values, and its consistency with statistical assumptions. The variables related to demographic and lifestyle data were then examined using
for each condition, as well as for completers versus non-completers, the appropriate non-parametric (for example, 2) or parametric (for example, t-test) statistic. internal consistency estimates
Each subscale of the BREQ-2R was given a (Coefficient; Cronbach, 1951) value for each time point. At baseline, Time 1, and Time 2, Pearson bivariate correlations between the variables of interest were calculated. The use of change scores across time allowed for the examination of association patterns. By using the baseline value to run linear regression analysis on each variable of interest, standardized residuals were first computed.
as the uncontrolled factor. The standardized residual for that variable was then created from the difference between the predicted and actual values (Zumbo, 2007). To find patterns of linkages between change scores (), Pearson bivariate correlations were computed between the standardized residuals of pertinent research variables. The study variables measuring BMI, PA, and behavioral regulations consistent with OIT were then subjected to a series of mixed model Analysis of Variance (ANOVAs) with one between groups variable (intervention or control) and one within groups variable (Time) to examine differences between conditions and changes over time. Effect size estimates (p2) were interpreted in addition to null hypothesis significance tests. Effect sizes of.01,.06, and.14 were categorized as modest, medium, and big, respectively, by Stevens (1996).