Development of the Impact of Physical Activity Scale.

Despite evidence that exercise has physical and mental benefits, there is still a high dropout rate. One reason for why people struggle to maintain consistency in their workout programs is self-efficacy, the cognitive mechanism that predicts behavioral intention. Given that emotional arousal plays an important role in self-efficacy, we developed the Impact of Physical Activity (IPA) scale to investigate how positive and negative affect influence commitment to exercise. The findings demonstrate good internal reliability of the scale, as well as convergent and divergent validity with optimism and depression. The IPA also had good predictive validity of physical self-efficacy.