Latar Belakang. DKI Jakarta memiliki tingkat ketidakaktifan tertinggi di Indonesia (55,7%). Mahasiswa rentan terhadap gaya hidup sedentari karena tekanan akademik. Intensi aktivitas fisik dipengaruhi oleh sikap, norma subjektif, persepsi kontrol, dan dukungan sosial di media sosial.
Tujuan. Studi ini meneliti hubungan antara dukungan sosial di Instagram dan faktor TPB dengan intensi aktivitas fisik pada mahasiswa di DKI Jakarta.
Metode. Studi cross-sectional pada November 2024 melibatkan 376 responden untuk meneliti intensi aktivitas fisik, sikap, norma subjektif, persepsi kontrol perilaku, dan dukungan sosial di Instagram menggunakan kerangka Theory of Planned Behavior (TPB). Data dianalisis secara univariat dan bivariat dengan uji chi-square.
Hasil. Mayoritas responden memiliki intensi aktivitas fisik tinggi sikap positif, norma subjektif positif, persepsi kontrol perilaku tinggi, serta dukungan sosial di Instagram yang cukup terhadap aktivitas fisik. Sikap, norma subjektif, persepsi kontrol perilaku, dan dukungan sosial di Instagram memiliki hubungan positif yang signifikan dengan intensi aktivitas fisik (p-value <0.001). Dukungan sosial di Instagram, serta faktor TPB, memengaruhi intensi aktivitas fisik pada mahasiswa di DKI Jakarta. Upaya promosi kesehatan dan intervensi perlu dirancang lebih spesifik melalui media sosial untuk membangun kebiasaan aktivitas fisik yang baik pada mahasiswa.

Background: Physical activity is essential for health, with WHO recommending 150 minutes of moderate to vigorous exercise per week to prevent chronic diseases. The 2023 SKI data indicates that DKI Jakarta has the highest inactivity rate (55.7%). University students are particularly prone to sedentary lifestyles due to academic pressures. Physical activity intention, influenced by attitudes, subjective norms, perceived control, and social support—especially via Instagram—plays a crucial role in predicting behavior. This study explores the relationship between Instagram social support and physical activity intention among students in DKI Jakarta. Methods: A cross-sectional study in November 2024 involving 376 respondents examined physical activity intention, attitudes, subjective norms, perceived behavioral control, and social support on Instagram using the Theory of Planned Behavior (TPB) framework. Data were analyzed univariately and bivariately using the chi-square test. Results: Most respondents showed high physical activity intention (58%). Additionally, they demonstrated positive attitudes, positive subjective norms, high perceived behavioral control, and sufficient Instagram social support regarding physical activity. Attitudes, subjective norms, perceived behavioral control, and Instagram social support had a significant positive relationship with physical activity intention (p-value <0.001). Conclusion: Social support on Instagram, along with attitudes, perceived behavioral control, and subjective norms, influences physical activity intention among students in DKI Jakarta. Health promotion efforts and interventions should be tailored through social media to foster better physical activity habits among students.