Reliability and validity of the Kinect V2 for the assessment of lower extremity rehabilitation exercises.

•Kinect V2 can reliably assess simple lower limb exercises, like the squat.•Reliability decreases with increasing complexity of the lower limb movement task.•Especially small movement amplitudes result in poor reliability.•Restricted validity for hip and knee angles and positions during some exercises.•An application in the field of early orthopedic rehabilitation is so far limited.