Key Message
This study assessed the impact of partial and total COVID-19 lockdowns on physical activity and sedentary behavior in Chilean adults aged 18–44 years. Although total physical activity and sitting time did not significantly differ between lockdown types, moderate physical activity was significantly lower during total lockdowns, particularly among females. A positive association between household area and moderate activity suggests that public health strategies should consider gender and living conditions to mitigate the negative effects of prolonged restricted movement.