Over the last few decades, the modern domestic pig has been genetically selected to maximise weight and length of back for meat production. Consequently, its body shape has changed and the physical acts of standing up and lying down have become difficult and relatively uncontrolled, even without any modification that housing systems may impose. Confined housing systems restrict the amount of exercise that locomotory muscles perform, and may affect muscular conformation and strength. It is possible, therefore, that confinement will decrease any element of muscular control during standing and lying, even further. The objective of this study was to determine any relationship between muscular conformation and time taken to lie down in sows housed in different dry sow systems.