OBJECTIVE AND HYPOTHESIS:

The objective of this study will be to examine the effects of watching a screen or listening to music while exercising on acute energy intake and expenditure. It is hypothesized that the post-exercise energy compensation will be greater in both conditions with stimuli (i.e., screen and music) compared with the control condition (i.e., exercise alone).

STUDY DESIGN:

Randomized, 3-condition crossover study (within-subjects experimental design).

PARTICIPANTS:

The present study will recruit 25 male adolescents between the ages of 13 and 17 years. Participants will be recruited via advertisements and word of mouth (first come first served approach).

OVERVIEW OF THE STUDY PROTOCOL:

Preliminary Visit The participants will attend one baseline session and three experimental sessions. The preliminary visit will include measurements related to anthropometry (body weight, height, waist circumference) and resting metabolic rate. Participants will also complete questionnaires in order to better characterize them.

Experimental Sessions Each participant will be engaged in each of the following three 30-min experimental conditions followed by an ad libitum lunch: (1) walking/jogging on a treadmill at 60% of VO2 peak while watching a screen (exercise + screen); (2) walking/jogging on a treadmill at 60% of VO2 peak while listening to music (exercise + music); and (3) walking/jogging on a treadmill at 60% of VO2 peak with no other stimulus (control condition).

MEASUREMENTS:

The main measures for this study include: anthropometric measurements, food intake, appetite sensations, energy expenditure, resting metabolic rate, and ratings of perceived exertion.

OUTCOME MEASURES:

The primary outcome measure will be post-exercise energy compensation. The food intake outcome will be assessed by using an ad libitum test meal immediately after the conditions and a dietary record for the remainder of the day. The energy expenditure outcome will be assessed by using an Actical accelerometer until bedtime. The secondary outcome measures will include appetite sensations and the ratings of perceived exertion (OMNI scale).

Inclusion Criteria:

- Male adolescents between 13 and 17 years

Exclusion Criteria:

• Smoking
• Unstable body weight (±4 kg) during the 3 months preceding testing
• Excessive alcohol intake (>15 drinks/week)
• Celiac disease
• Metabolic disease (e.g., thyroid disease, heart disease, diabetes)
• Medication use that could interfere with the outcome variables
• Irregular sleeping pattern (e.g., shift work or working overnight shifts)
• Iinability to comply with the protocol.