Because of the growing demand of geriatric rehabilitation, objective and clear indication decisions are needed with respect to limited financial resources. The aim of an interdisciplinary consensus group was to critically evaluate the most commonly used tests of functional performance of the lower limbs and to recommend useful tests to document progress of inpatient rehabilitation. Assessment of standing, walking, walking with a dual-task, sit-to-stand transfer, lying-to-sit-to-stand transfer, and stair climbing were recommended to document functional performance of the lower limbs and to describe rehabilitation targets. Future research is needed, because reasonably validated assessment tools do not exist for all of these domains. In addition to a standardized assessment of physical capacity, physical activity and participation with regard to the International Classification of Functioning, Disability, and Health (ICF) context have to be assessed. Body fixed sensors seem to be a promising assessment tool to objectively document progress in rehabilitation.