Repeatability of an optimised lower body model.
The optimisation technique, optimised lower-limb gait analysis (OLGA), is described together with a preliminary study of repeatability compared to an implementation of the Newington-Helen Hayes gait model. The study of repeatability used a single healthy subject, three physiotherapists as observers and provided approximately 100 gait cycles. Improvement in intra- and inter-observer repeatability of the lower limb model was found for OLGA, indicated by significantly lower standard deviations (S.D.s) in local marker co-ordinate (a measure of rigidity of the marker attachment), together with reduced S.D. in the estimated length of the bone segments. The S.D. in the inter-hip distance measured by OLGA (N = 25) was found to be only 2.4 mm. The repeatability of clinically significant output variables (joint angles, forces and moments) was also improved, with the inter-observer variations for joint angles and forces being significantly lower for OLGA. Euler angle component cross-talk effects frequently reported at the hip, knee and ankle were also successfully reduced by OLGA, this being the chief cause of the improvement in inter-observer repeatability.
Charlton
I W
IW
Vicon Motion Systems Ltd., 14 Minns Business Park, West Way, Oxford OX2 OJB, UK. i.charlton@vicon.com
Tate
P
P
Smyth
P
P
Roren
L
L
D000465:Algorithms; D000843:Ankle Joint / Q000033:anatomy & histology / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006615:Hip / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology / Q000502:physiology*; D008962:Models, Theoretical; D015588:Observer Variation; D015203:Reproducibility of Results