Understanding strength exercise intentions and behavior in hematologic cancer survivors: an analysis of the intention-behavior gap

Strength exercise improves many health outcomes in cancer survivors but the prevalence and correlates of strength exercise have not been well-described. Moreover, no study has examined the critical intention-behavior gap for exercise in cancer survivors.

The aims of this study are to quantify the intention-behavior gap for strength exercise in hematologic cancer survivors (HCS) and examine correlates of both intention formation and translation using the multi-process action control framework (M-PAC).

A random sample of 2100 HCS in Alberta, Canada, were mailed a survey assessing strength exercise behavior, the M-PAC, and demographic/medical variables. Separate logistic regressions were used to analyze the relationships between the correlates and intention formation and translation.

Surveys were completed by 606 HCS with 58 % (n = 353) intending to do strength exercise. HCS who were not retired (OR = 1.56, p = 0.001), were highly educated (OR = 1.32, p = 0.001), and had a favorable attitude (OR = 1.56, p < 0.001), descriptive norm (OR = 1.38, p = 0.006), injunctive norm (OR = 1.45, p = 0.004), and perceived control (OR = 1.38, p < 0.001), were more likely to form an exercise intention. Of those with an exercise intention, 51 % (n = 181) reported regular strength exercise. HCS with a detailed plan (OR = 1.86, p < 0.001), favorable attitude (OR = 1.68, p = 0.001), sense of obligation (OR = 1.38, p = 0.010), and self-regulated their affinity for competing activities (OR = 1.35, p = 0.012), were more likely to translate their intention into behavior.

Just over half of HCS intended to do strength exercise and only half of intenders translated that intention into behavior.

Interventions targeting both intention formation and translation may provide the best approach for increasing strength exercise in HCS.