This study will be an 8-week randomized controlled trial examining the effects of a YouTube-delivered aerobic and muscle strengthening physical activity intervention on university students' physical activity, fitness, sleep quality, and psychosocial health outcomes. Participants will be randomized into 1 of 2 groups: (1) intervention group (receive twice-weekly YouTube videos [1 aerobic workout video; 1 muscle-strengthening workout video] for 8 weeks); or (2) control group (receive twice-weekly YouTube videos with general health information [no physical activity-related information or workouts] for 8 weeks). Baseline (0 weeks), mid-point (4 weeks), and post-test (8 weeks) testing will take place and the following outcome measures will be assessed at these time points: participants' free-living (7-day) objectively-measured physical activity and sleep quality data will be collected; anthropometric measures (height, weight, percent body fat); cardiorespiratory and muscular fitness; and psychosocial assessments (perceived physical activity barriers and social support).

Inclusion Criteria:

• 18-35 years of age; able to participate in aerobic and muscle-strengthening exercise; healthy (i.e., no diseases or clinical/mental health conditions which will prevent physical activity participation); does not meet minimum physical activity guidelines criteria for aerobic (≥ 150 minutes per week of moderate-to-vigorous intensity physical activity) and muscle-strengthening (≥ 2 days per week; 8-10 exercises for all major muscle groups) physical activity at time of enrollment; willing to be randomized to the intervention or control group.

Exclusion Criteria:

• less than 18 years old or greater than 35 years old; physical or mental health contradictions which do not allow participants to participate in physical activity; exceed minimum aerobic or muscle-strengthening physical activity guideline recommendations; unwilling to be randomized to either intervention or control group.