Explaining Sedentary Behavior With Planning (the Revised HAPA Model)
Explaining Sedentary Behavior With Planning (the Revised HAPA Model)
This study would investigate the effects of forming action plans on a reduction of sedentary
 behaviors. Participants will be randomly assigned to either active control group (education
 on sedentary behaviors and physical activity) or the intervention group (forming action plans
 referring to replacing sedentary activities with physical activity. The effects of the
 intervention will be evaluated at the 2-month follow-up and at the 8-month follow-up.
The effects of three sessions (3 education sessions versus 3 education sessions+ forming
 plans to replace sedentary behavior with physical activity) will be investigated among
 participants from three age groups: adolescents (12-17 years old), adults (18-60 years old),
 and older adults (>60 years old). Compared to education only, forming plans about how to
 replace time spent on sedentary activities with physical activity is expected to result in a
 significantly larger change (a reduction) of sedentary time at the follow-up. Accelerometers
 will be used to evaluate short-term and mid-term changes in total sedentary time and the
 relative proportion of time spent on sedentary behavior vs light-intensity and
 moderate-to-vigorous- intensity physical activity.

 Additionally, the study will observe changes in if the cognitions included in the Health
 Action Process Approach model (HAPA), such risk perception, self-efficacy, outcome
 expectancies, intention, action control, as well as changes in behavioral habit, presence of
 sedentary behavior cues in physical environment, and physical activity behavior. The
 observations will be conducted three times, at the baseline (before the intervention), the
 2-month follow up, and at the 8-month follow-up.
Inclusion Criteria:

 -  not meeting physical activity guidelines proposed by the World Health Organization

 Exclusion Criteria:

 -  any existing diseases with contraindications for moderate intensity physical activity,
 confirmed by patient's primary care physician or a specialist in cardiovascular
 diseases/endocrinology/rehabilitation medicine providing care for the patient during
 the recruitment and follow-ups