Exercise Snacks and Muscular Fitness in Sedentary Young Women

Effects of a 75-Minute Weekly Exercise Snack on Muscular Fitness in Sedentary Young Women

This randomized controlled study examined whether exercise snacks could improve skeletal muscle strength and related physical fitness in sedentary female university students. Eligible participants were sedentary women aged 18 to 25 years who were randomly assigned to an exercise snacks group, a regular exercise group, or a control group. The intervention lasted 8 weeks. The exercise snacks group accumulated short bouts of exercise across the day, while the regular exercise group completed more concentrated exercise sessions three times per week. The control group maintained their usual lifestyle. Muscle strength and related physical fitness were assessed before and after the intervention. The study aimed to evaluate the effectiveness, feasibility, and safety of exercise snacks in a university setting.

Sedentary behavior is common among university students and may contribute to reduced physical fitness and lower skeletal muscle function. Exercise snacks are short bouts of physical activity performed repeatedly throughout the day and may offer a time-efficient strategy for interrupting prolonged sitting.

This single-center randomized controlled study was conducted at Chongqing Normal University. Sedentary female university students aged 18 to 25 years were screened for eligibility. Participants completed baseline assessments and were randomly allocated to an exercise snacks group, a regular exercise group, or a control group.

The intervention lasted 8 weeks. The exercise snacks group performed short exercise bouts distributed throughout the day, with a total weekly exercise volume of approximately 75 minutes. The regular exercise group performed exercise three times per week, with each session lasting approximately 25 minutes. Both intervention groups received exercise guidance, reminders, adherence monitoring, and ratings of perceived exertion through the Tizhiyun mobile application. The control group maintained their usual study and lifestyle routines without additional study-prescribed exercise.

Primary outcomes included isokinetic muscle strength, surface electromyography, and mid-thigh isometric pull performance. Secondary outcomes included standing long jump, knee push-ups, and bodyweight squats to exhaustion. Outcome assessments were conducted at baseline and after the 8-week intervention. Adherence, perceived exertion, and exercise-related adverse events were recorded during the study period.

Inclusion Criteria:

• Female university students aged 18 to 25 years.
• Daily sedentary time of at least 8 hours, assessed using a sedentary behavior questionnaire.
• No contraindications to exercise based on the Physical Activity Readiness Questionnaire.
• No regular exercise participation during the previous 3 months.

Exclusion Criteria:

• Clinical conditions that make participation in exercise inappropriate.
• Substantial body weight fluctuation during the previous 3 months.
• Hypertension, cardiovascular or cerebrovascular disease, or use of related medications.