Advancements in measurement of human motion

An increasing number of professional disciplines is interested in analysis of human motor behavior to assess its functioning or performance, e.g. rehabilitation medicine, orthopedics, physiotherapy, ergonomics, experimental psychology and sports. Besides observational analysis of human motion, state of the art methods provide accurate measurements of the kinematics of posture and movement, muscle activation patterns and external forces. These measurements enable the use of biomechanical models to provide a comprehensive assessment. Traditionally the most accurate methods apply some sort of video-based marker tracking methods. By tracking data with multiple fixed position cameras, 3D posture and motion data is gathered. Together with muscle activation data (gathered as electromyographic signals) and forces exchanged with the outside world (typically through the feet and measured with force plates in the floor) a complete assessment of performance or problems can be made. This comprises human motor control as well as the mechanical loading of the musculoskeletal system. However, fixed cameras and the fixed force plate limit possible motions and actions of the subject. Also the required stereophotogrammetric equipment requires high investments and a motion analysis session is typically a very time-consuming effort. So analysis of human movement (including gait analysis) is exclusively available to some (academic) laboratories. Currently technical and methodological alternatives are becoming available that form relatively cheap alternatives which are also very easy to apply in (clinical) practice. These methods promise to facilitate accurate motion analysis in any room or even in situations in which the subject is freely roaming about. This Special Interest Group introduces several new developments in miniature sensing and marker-less video motion analysis in a workshop in which all aspects of practical ambulatory or locationindependent motion analysis are discussed.