Shaelyn M. Strachan

Sensitivity to reward: implications for overeating and overweight

Sensitivity to reward (STR)-a personality trait firmly rooted in the neurobiology of the mesolimbic dopamine system-has been strongly implicated in the risk for addiction. This construct describes the ability to derive pleasure or reward from natural reinforcers like food, and from pharmacologic rewards like addictive drugs. Recently experts in the field of addiction research have acknowledged that psychomotor stimulant drugs are no longer at the heart of all addictions, and that brain circuits can also be deranged with natural rewards like food. The present study tested a model in which STR was expected to relate positively to overeating, which in turn would be associated with higher body weight in woman aged 25-45 years. As predicted, STR was correlated positively with measures of emotional overeating. Also, overweight woman were significantly more sensitive to reward than those of normal weight. Interestingly, however, the obese woman (Body Mass Index>30) were more anhedonic than the overweight woman (Body Mass Index>25<30). These findings are discussed in the context of neuroadaptations to overactivity of brain reward circuits. Results also indicate that STR may serve as a risk factor for overeating and overweight, especially in cultures such as ours where palatable, calorically-dense food is plentiful.

Healthy-eater Identity and Self-efficacy Predict Healthy Eating Behavior: A Prospective View

Identity and Self-efficacy Theories were used to examine the relationship between healthy-eater identity, self-efficacy for healthy eating and healthy eating. Measures of healthy-eater identity, perception of healthy eating, nutrition knowledge, self-efficacy for both intake of fruits and vegetables and foods of low nutritional value were completed by 101 university students and staff. Two weeks later, participants recalled recent consumption of (a) fruits and vegetables and (b) foods of low nutritional value. For both eating outcomes, healthy-eater identity was a significant predictor after controlling for nutrition knowledge. The addition of self-efficacy improved prediction in the case of both eating outcomes.

Reactions to a Perceived Challenge to Identity: A Focus on Exercise and Healthy Eating

Based upon Identity and Social Cognitive theories, two studies examined reactions to challenges to exercise identity (Study 1) and healthy-eater identity (Study 2). For both studies, participants responded to a perceived challenge relative to the health behavior in terms of affect, intentions, self-regulatory efficacy and generated self-regulatory strategies. High identity participants in both studies showed the theory-based, hypothesized response pattern suggesting they were seeking identity-behavior congruency and this response pattern was stronger than exhibited by moderate identity individuals. Collectively, findings support the compatible use of Identity and Social Cognitive theories in studying identity and suggest that identities may be important in understanding health behavior regulation.

Strength of Exercise Identity and Identity-Exercise Consistency Affective and Social Cognitive Relationships

This study examined Identity Theory hypotheses about identity—behaviour consistency. Exercise-identity strength and judgments about consistency were hypothesized to relate to perceptions of percent consistency and frequency of vigorous exercise. Identity strength and percent consistency were hypothesized to interact in their relationship with affective reactions to extent of consistency. Measures of exercise-identity strength, perceived consistency, exercise frequency, self-regulatory efficacy and consistency-related affect were completed by 528 exercisers. Exercise-identity strength and consistency judgments related to percent consistency and exercise frequency. Exercise-identity strength and percent consistency interacted in their relationship with consistency-related affect and also were related to self- regulatory efficacy.

Narratives of Athletic Identity After Acquiring a Permanent Physical Disability

Individuals with acquired physical disabilities report lower levels of athletic identity. The objective of this study was to further explore why athletic identity may be lost or (re)developed after acquiring a physical disability. Seven women and four men (range = 28-60 years) participated in approximately 1-hour-long semistructured interviews; data were subjected to a narrative analysis. The structural analysis revealed three narrative types. The nonathlete narrative described physical changes in the body as reasons for diminished athletic identity. The athlete as a future self primarily focused on present sport behavior and performance goals such that behavior changes diminished athletic identity. The present self as athlete narrative type focused on the aspects of their present sport involvement, such as feedback from other athletes and skill development, which supported their athletic identity. Implications of these narrative types with respect to sport promotion among people with acquired physical disabilities are discussed.

Varying the cause of a challenge to exercise identity behaviour: reactions of individuals of differing identity strength.

Research shows that people with stronger exercise identity (EXID) exhibit greater negative affect and self-regulatory efficacy (SRE) when behaviour is inconsistent with identity. However, related attributions have not been examined. Using social cognitive and identity theories, we examined causes of failing to exercise. In a two (EXID: stronger, weaker) by two (Cause: personally-controllable, situational) design, participants (N = 224) were randomized to Cause and read a condition-relevant no-exercise vignette. MANOVA revealed main effects for Cause and EXID, p’s < .001. Participants explaining their Cause differed on attributional dimensions, and stronger EXID participants reported greater negative affect and higher SRE, p’s < .001.

‘Don't be scared, you don't have to wear your lifejacket’: using the theory of planned behaviour to understand lifejacket usage in Tuktoyaktuk, Northwest Territories, Canada

Water related activities result in a large number of fatalities annually throughout Canada, especially in the Canadian north, where drowning rates are up to ten times the national average. This study used participant observation, semi-structured interviews, and archival research to understand why residents of Tuktoyaktuk, Northwest Territories (NWT) rarely wear lifejackets. Three themes emerged. Firstly residents largely perceive lifejackets to be inaccessible, secondly drownings are attributed to factors other than failing to wear a lifejacket and thirdly lifejacket use is not encouraged by important individuals in the community. It is suggested that successful lifejacket promotion for this population requires drowning prevention programmes that move away from simplistic approaches that encourage people to wear lifejackets and instead must utilise an approach that addresses each component of the theory of planned behaviour (TPB).

Testing a longitudinal integrated self-efficacy and self-determination theory model for physical activity post-cardiac rehabilitation

Self-determination theory and self-efficacy theory are prominent theories in the physical activity literature, and studies have begun integrating their concepts. Sweet, Fortier, Strachan and Blanchard (2012) have integrated these two theories in a cross-sectional study. Therefore, this study sought to test a longitudinal integrated model to predict physical activity at the end of a 4-month cardiac rehabilitation program based on theory, research and Sweet et al.’s cross-sectional model. Participants from two cardiac rehabilitation programs (N=109) answered validated self-report questionnaires at baseline, two and four months. Data were analyzed using Amos to assess the path analysis and model fit. Prior to integration, perceived competence and self-efficacy were combined, and labeled as confidence. After controlling for 2-month physical activity and cardiac rehabilitation site, no motivational variables significantly predicted residual change in 4-month physical activity. Although confidence at two months did not predict residual change in 4-month physical activity, it had a strong positive relationship with 2-month physical activity (β=0.30, P<0.001). The overall model retained good fit indices. In conclusion, results diverged from theoretical predictions of physical activity, but self-determination and self-efficacy theory were still partially supported. Because the model had good fit, this study demonstrated that theoretical integration is feasible.

Sedentary Behavior, Cadence, and Physical Activity Outcomes after Knee Arthroplasty.

Purpose This study comprehensively examined sedentary behavior and physical activity patterns in people with severe knee osteoarthritis awaiting total knee arthroplasty (TKA) and in individuals after TKA. Methods Preoperative (n = 32, mean ± SD = 69.9 ± 5.3 yr) and 1-yr postoperative participants with TKA (n = 38, 67.9 ± 7.3 yr) wore ActiGraph GT3X+ activity monitors for 6.8 ± 0.6 d. Total sedentary time, time in long sedentary bouts (≥30 min), and physical activity outcomes (steps, time in moderate-to-vigorous physical activity [MVPA], cadence) were examined. Results There were no differences between pre- and postoperative groups for total sedentary time (9.3 ± 1.4 vs 9.2 ± 1.4 h·d−1, P = 0.62) and number of long sedentary bouts per day (median [interquartile range] = 3.4 [1.9] vs 3.1 [2.0], P = 0.37). Daily steps, peak 30-min cadence, and peak 1-min cadence values were greater in people after TKA compared with those awaiting surgery (5935 [3316] vs 3724 [2338], 55.6 [31.0] vs 35.9 [19.3], and 91.5 ± 20.6 vs 70.0 ± 23.7, respectively, all P < 0.01). There were no differences in lifestyle MVPA between groups. The number of bouts of Freedson MVPA was greater in postoperative participants, but the differences were not substantial (one bout per week). Conclusion Patients report less knee pain and improved function after TKA; however, sedentary behavior does not differ and physical activity is only marginally increased compared with those awaiting surgery. After TKA, daily walking at slow, moderate, and brisk paces and engagement in MVPA do not match levels seen in healthy older adults, which, when combined with high levels of sedentary behavior, leaves patients at increased risk for physical disability and cardiovascular disease.

Understanding variations in exercise-identity strength through identity theory and self-determination theory

Using identity theory and self-determination theory (SDT), this study examined whether exercise-identity strength was associated with behavioural regulations for exercise (including integrated regulation). Further, this study assessed whether exercise identity and behavioural regulations interacted in their relationship with the self-regulation of exercise. This study was observational involving self-report. Data were collected at two time points, 1 month apart. Community exercisers (N = 100; mean age = 32.71 years) completed validated measures of identity strength, behavioural regulations, and self-regulation relative to exercise. As hypothesized, exercise identity was most significantly correlated (p < 0.001) with the more self-determined forms of behavioural regulation including identified (r = 0.72), integrated (r = 0.82), and intrinsic (r = 0.58) regulations. Further, identified regulation moderated the relationship between exercise identity and self-regulation (p < 0.001). Overall, this study suggests that variations in exercise-identity strength may be characterized by differential regulation of exercise. Further, exercise-identity strength and identified regulation may interact in their relation to exercise self-regulation. Finally, results support the complementary use of identity theory and SDT; ideas to advance this line of inquiry are discussed.