Abstract
With increases in physical activity (PA) levels of females (Schultz, 2004), research has focused on how menstrual hormones affect performance (e.g., Janse de Jonge, 2003). Limited research has examined how the menstrual cycle may relate to PA participation (Croteau et al., 2015; Held, 2013). This study explored how the components of the Theory of Planned Behavior (TPB: attitudes, subjective norms, perceived behavioral control (PBC), intention) and self-reported PA varied throughout the menstrual cycle while considering oral contraceptive use (OC). Females (N=21) completed a diary daily (M=36.6 days) via text message. Participants reported body temperature (identification of menstrual, proliferative, and secretory phases), time spent in the previous days' PA, intention, attitude, subjective norms, and PBC. Using multilevel modelling, each component of the TPB was predicted using two dummy variables reflecting the cycle phase, the use of OC as well as the interaction between phase and OC use. Interactions between OC use and being in the menstrual phase (i.e., experiencing menstruation) were identified for attitude (p=.02), norms (p=.04), and approached significance for PBC (p=.10). For attitude and PBC, lower perceptions occurred during menstruation for those not on OC but did not differ for OC users. Norms for PA were higher during menstruation for OC users but did not differ for non OC users. There were no differences for intention and PA. OC users generally displayed positive perceptions toward PA during menstruation than those not on OC, which suggests a consideration of the menstrual cycle and OC use when exploring perceptions towards PA.
