Assessing lumbar stabilization from point-light and normal video displays of manual lifting

Routinely, physical therapists use visual observation to assess qualitatively a patient's performance. The literature, however, indicates that assessments of gait and lumbar stabilization from visual observation are at best only moderately reliable. Point-light video displays have been used to study the visual perception of human motion. The present purpose was to examine the reliability of assessments made by a physical therapist when viewing point light and normal video displays of subjects performing a lifting task. Three physical therapists assessed lumbar stabilization by viewing normal and point-light displays of 25 subjects who lifted an 8-lb. milkcrate from floor to waist height. Greater agreement of the therapists' ratings of lumbar stabilization was achieved on assessments made from point-light displays than on those made from normal displays. This finding suggests that the use of point-light displays may improve the reliability of qualitative assessments of performance on motor tasks.