Intervention effects of exercise self-regulation on physical exercise and eating fruits and vegetables: a longitudinal study in orthopedic and cardiac rehabilitation

OBJECTIVE

The primary objective of this study was to unveil the mechanisms by which an exercise self-regulation intervention affects physical exercise in a rehabilitation context. The second aim was to investigate whether the intervention led to changes in fruit and vegetable intake that was not targeted in the intervention. Finally, it was tested whether changes in exercise habit strength may explain such a transfer effect.

METHOD

A quasi-experimental design was conducted in Germany between 2009 and 2011 with 725 rehabilitation patients. Patients received either a self-regulation intervention or an online questionnaire. Six weeks after discharge, self-reported changes in exercise and dietary behaviors, exercise habit strength, and cognitions were measured. QUANTITATIVE RESULTS: The exercise self-regulation intervention led to a higher increment in exercise behavior, exercise habit strength, and fruit and vegetable intake than the control condition. Changes in physical exercise were mediated by changes in action control (slope=0.04; 99% CI=0.01 to 0.06) and satisfaction (slope=0.05; 99% CI:=0.02 to 0.08), but not in action planning. Changes in fruit and vegetable intake were mediated by changes in exercise habit strength (slope=0.05; 99% CI=0.01 to 0.08).

CONCLUSION

Interventions could be optimized if they aim at fostering exercise habits. This in turn may also facilitate transfer effects from one health behavior to the other.

Validity of a stage algorithm for physical activity in participants recruited from orthopedic and cardiac rehabilitation clinics

OBJECTIVE

For stage-matched interventions, individuals must be classified with respect to their previous behaviors and in conjunction with their future intentions. A novel procedure for the assessment of stages in physical activity was developed. For this, individuals' activity and their regarding intentions were compared with recommended levels of activity. The aim was to examine the psychometric properties.

DESIGN

In a cross-sectional study, stages were assessed in 366 study participants (84 in cardiac and 282 in orthopedic rehabilitation) in terms of their previous physical activity and their intention to perform recommended activity levels in the future.

MAIN OUTCOME MEASURES

Stages of change were compared to self-reported behavior, intention, planning, self-efficacy, risk perception, pros, cons, and social support. Misclassification, sensitivity, specificity, receiver operating characteristic (ROC) curves, non-linear trends, and planned contrasts were computed.

RESULTS

In comparison to previous studies, sensitivity (44%-99%) was high and specificity was similar or low (3%-88%), depending on the type of validation outcome selected. When using less demanding criteria (i.e., less intensive activity), measurement quality decreased, although not always significantly. Applying contrast analyses, more than half of the predicted stage differences were confirmed. No main differences between orthopedic and cardiac, ambulant and stationary rehabilitation appeared and no interactions were found.

CONCLUSION

The stage algorithm proved to have acceptable measurement qualities in study participants recruited in both cardiac and orthopedic rehabilitation. Especially in detecting Intenders and Actors the stage algorithm performed well. Mechanisms of adopting and maintaining recommended activity levels seem to operate equally in both groups.

Förderung von körperlicher Aktivität im betrieblichen Kontext

Zusammenfassung. Theoriebasierte Interventionen zur Förderung von körperlicher Aktivität können auf Stadien der Verhaltensänderung maßgeschneidert werden. Die Grundlage hierfür liefern Stadienmodelle. Diese nehmen an, dass für den erfolgreichen Übergang von einem Stadium zum nächsten unterschiedliche sozial-kognitive Variablen bedeutsam sind. Ziel der Studie war es, stadienspezifische Effekte von stadienpassenden Interventionen auf körperliche Aktivität und sozial-kognitive Prädiktoren im betrieblichen Kontext zu untersuchen. 839 Mitarbeiter eines Großunternehmens wurden randomisiert einer stadienpassenden Intervention und einer stadien-unspezifischen Standardmaßnahme zugewiesen. Vor der Intervention sowie vier Wochen später wurden Zielsetzung, Planung und körperliche Aktivität erfasst. Die Datenanalyse erfolgte mittels Varianzanalyse mit Messwiederholung. Die stadienpassenden Interventionen erhöhten die stadienspezifischen Variablen effektiver als die Standardmaßnahme. Stadienpassende Interventionen scheinen effektiver zu sein als stadien-unspezifische Standardmaßnahmen. Neben Verhaltensmaßen sollten auch Veränderungen in sozial-kognitiven Variablen zur Evaluation von Interventionen herangezogen werden.