| Text messages can encourage people to carry out their plans, but it is unknown if text messages can encourage people to form plans. The primary objective of our study was to determine whether text messages could promote physical activity plan formation. We determined if text messages about planning increased planning more than text messages about physical activity. We examined whether messages tailored to suit the individual message recipient were especially effective in encouraging planning. Furthermore, we determined if planning was maintained over time. The secondary objective of the study was to determine whether text messages about planning could promote physical activity and strengthen the physical activity intention-behaviour relationship. Participants were inactive adults (n=239, Mage=30.7+/-4.8yrs) with access to email and text messaging. Participants received generic messages about physical activity, generic messages about planning, or tailored messages about planning. Each week for two months, participants were emailed a tool to plan their physical activity. Whether participants used this tool was assessed at baseline (T0), after one month of receiving text messages (T1) and after an additional month without text messages (T2). There were no differences in planning between groups that received messages about planning or physical activity at T1 or T2, ps>.05. More participants who received tailored text messages about planning made at least one plan by T1 than participants who received generic messages about planning, chi2(1)=3.889, p.05. For all groups, planning was maintained from T0 to T1, ps>.05, but decreased from T1 to T2, McNemars chi2(1)>17.455, ps<.001. Physical activity increased over the intervention, ps.05. The strength of the intention-behaviour relationship did not differ between participants who planned and those who did not, p>.05. There seems to be little advantage to sending messages about planning relative to messages about physical activity for persuading planning behaviour. Regardless of content of the messages, planning may not be sustained over time. |
