============================================================================ ======= ***** *** * * *** * * ======== ======= * * * * * * * ** * ======== ======= * * * ***** ***** * * * ======== ======= * * * * * * * * * ======== ======= ** *** * * * * * * ======== ============================================================================ ReadMe.txt file Version 1.0 ============================================================================ Full body model for Centre Of Mass Position Michael Eames, Belfast 1999 With a little tidying up from Richard Baker Named in honour of Johan Sebastian Bach who worked out his COM-positions with mathematical precision! Whilst every effort has been made to validate this model and ensure that it is free from error, this cannot be guaranteed and users must conduct their own tests to convice themselves of its appropriateness for their particular application. Any corrections or general comments are welcome and should be e-mailed to richard.baker@greenpark.n-i.nhs.uk. ============================================================================ This file comes in a zipped file which includes: Johan.mod (this file) containing basic model. Johan.mp a template parameter file. Johan.mkr a markerset file including support for autolabelling *} ReadMe.txt giving a overview of this software package. Johan.doc a Micorsoft Word '97 version of a paper describing the validation of this model which has been accepted for publication in Human Movement Science. ============================================================================ Introduction ============================================================================ Welcome to Johan. This model calculates the total body centre of mass (CM) using 12 body segments defined from 28 skin markers. The model is written for "Bodybuilder"(Oxford Metrics) in "BodyLanguage". We have validated the model using the second integral of the ground reaction force data, and have shown less than 0.4% height difference between the output from the model and GRF for normal adults, children and children with myelomeningocoele. A paper describing the validation has been accepted for publication in Human Movement Science. ============================================================================ Requirements ============================================================================ This model will not work unless you have BodyBuilder version 3.51 build 116 or higher. You can check this by clicking |help|About BodyBuilder... from within BodyBuilder. Talk to your VICON supplier if you have an earlier version. ============================================================================ Markers ============================================================================ MARKER POSITION (Centre of anatomical landmark, unless otherwise stated) Forehead Glabellum Mastoid (x2) Mastoid process Acromium (x2) Lateral aspect of each acromium Upper arm wand (x2) Mid shaft humerus in line with acromium and lateral epicondyle. Elbow (x2) Lateral epicondyle humerus Radius (x2) Radial styloid process Ulna (x2) Ulnar styloid process ASIS(X2) Ant. Sup. Iliac Crest Sacrum Mid point of PSIS. This must be a skin mounted marker. Use of a wand will introduce errors. Thigh wand(X2) Lower shaft femur in line of Gt trochanter to Lat. condyle. Knee(X2) Lat. condyle femur Tibial wand(X2) Lower shaft of tibia in line of lat. condyle femur to lat. mal. Ankle(X2) lat mal. Heel(X2) Os calcus (neede for static AND dynamic test) Toe(X2) Base of 1st Metatarsal. ============================================================================ Method ============================================================================ Capture data and label markers. To time normalise cycle to 50 frames input frame number of heel strike (left or right) into parameter file ($start), followed by heel strike at end of cycle ($End). For time normalisation ensure $Normalise = 1 (0 = Normalise off). Input age and other parameters (all in mm or degrees). Run Johan model. CofM = Centre of mass (not normalised) CofP = Centre of pelvis (centroid of ASIS and sacral markers). nCofMDiff% = Distance of CofM from the trajectory it would have taken in travelling from its position at the start of the normalisation period to the end of the normalisation period with uniform velocity, normalised to 51 values in time and as a % of height. Value is refereced to mean value over the entire normalistaion period. Good luck................... Michael Eames, meames@dnet.co.uk, October 1998. With a little tidying from Richard Baker, richard.baker@greenpark.n-i.nhs.uk, December 1998