Ali bin Hanzalah narrates from his father that Sayyiduna Umar (may Allah be pleased with him) said: "A man is not answerable for himself when he is starved, bound or beaten."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 15107
Al-Qasim bin Abd al-Rahman (may Allah have mercy on him) narrates from Qadi Shurayh (may Allah have mercy on him) that confinement, beating, shackling and threatening are coercion.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 15108