MCAT Practice Test 11

Promoting Physical Activity on Campus

¹Researchers compared three strategies for increasing daily walking among sedentary university students, defined as those averaging fewer than 7,000 steps per day at baseline.

²Two hundred students wore activity trackers for 12 weeks and were randomly assigned to four arms (n = 50). Control participants received the tracker and step feedback only. Reward participants earned points, exchangeable for cafeteria credit, on every day they reached 10,000 steps during weeks 1–6. Modeling participants watched weekly videos in which students similar in age and starting fitness described how they gradually increased their walking and were shown reaching step goals. Commitment participants, in week 1, recorded a short video posted on a campus health website urging other students to walk more, and then listed recent occasions when they had chosen to drive or sit instead of walk. All participants received a flat $20 for completing the study. All interventions ended after week 6. Trackers synced automatically, so step counts did not depend on self-report.

³Mean daily step counts are shown in Figure 1; the standard error was about 0.3 thousand steps at each time point. From baseline to week 12, self-efficacy for exercise (7-point scale) rose by 1.4 points in the modeling arm, 0.6 in the commitment arm, 0.2 in the reward arm and 0.1 in the control arm.

⁴Enjoyment of walking, a measure of intrinsic motivation, fell in the reward arm from 4.8 at baseline to 3.9 at week 12 and was unchanged in the other arms. In exit interviews, reward participants often described walking as "something I did for the points."