Muscular Changes in the First 12 Weeks After Stroke.

The investigators will use 3D freehand ultrasound to investigate changes in muscle morphology of the paretic m. rectus femoris and m. gastrocnemius medialis during the first 3 months after stroke. Additionally, 2D ultrasound and surface EMG will be synchronized to examine muscle activation and morphological changes resulting from this activation. Clinical tests will be conducted on the same test occasions to objectify lower limb impairment and gait recovery. As such, the investigators will explore the relationship between the muscle specific changes and functional recovery.