Subjective norm. Subjective norm was measured by 5 items rated on a 7-point Likert-type scale. The three items that assesse injunctive norm were preceded by the stem “I think that if I participated in regular PA over the next month, most people who are important to me would be…” followed by response options ranging from 1 ¼ extremely disapproving to 7 ¼ extremely approving, 1 ¼ extremely discouraging to 7 ¼ extremely encouraging, and 1 ¼ extremely unsupportive to 7 ¼ extremely supportive. The two items that assessed descriptive norm were: (1) “I think that over the next month, most people who are important to me will be…” followed by response options ranging from 1 ¼ extremely inactive to 7 ¼ extremely active; and (2) “I think that over the next month, most people who are important to me will themselves participate regularly in PA” followed by response options ranging from 1 ¼ strongly disagree to 7 ¼ strongly agree. Cronbach's alpha coefficients of internal consistency were 0.93 and 0.87 for injunctive and descriptive norms, respectively.