title: Accuracy of visual estimates of joint angle and angular velocity using criterion movements.
abstract: A descriptive study to document undergraduate physical education majors' (22.8 +/- 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images of the movements were analyzed with Peak Motus to measure actual values of elbow angles and peak angular velocity. Of the subjects 85.7% had speed ratings significantly correlated with true peak elbow angular velocity in all three angular velocity conditions. Few (16.7%) subjects' ratings of elbow angle correlated significantly with actual angles. Analysis of the subjects with good ratings showed the accuracy of visual ratings was significantly related to speed, with decreasing accuracy for slower speeds of movement. The use of criterion movements did not improve the small percentage of novice observers who could accurately estimate body angles during movement.
authors.affiliation: Southern Utah University, USA.
authors.forename: Craig S
authors.initials: CS
authors.lastname: Morrison
authors.forename: Duane
authors.initials: D
authors.lastname: Knudson
authors.forename: Colby
authors.initials: C
authors.lastname: Clayburn
authors.forename: Philip
authors.initials: P
authors.lastname: Haywood
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004551:Elbow Joint / Q000502:physiology; D005260:Female; D006801:Humans; D007600:Judgment; D008297:Male; D009039:Motion Perception; D009068:Movement / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D014743:Videotape Recording; D014796:Visual Perception