172 research outputs found
Support polygons and symmetrical gaits in mammals
No full textCartmill, M., Lemelin, P., Schmitt, D. (2002): Support polygons and symmetrical gaits in mammals. Zoological Journal of the Linnean Society 136 (3): 401-420, DOI: 10.1046/j.1096-3642.2002.00038.x, URL: https://academic.oup.com/zoolinnean/article-lookup/doi/10.1046/j.1096-3642.2002.00038.
Figure 10 in Support polygons and symmetrical gaits in mammals
No full textFigure 10. Running gaits (Sh Sf) in our data, plotted on the Hildebrand diagram. The arrow ('trot line') indicates the diagonality predicted for running gaits (D = 50).Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 413, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
Figure 12 in Support polygons and symmetrical gaits in mammals
No full textFigure 12. Modified Hildebrand diagram for our data set: revised support-polygon model. The relevant duty factor in each case – which is now Sf for L-S, D-C gaits (Rule 2: D = 100 – Sf) and Sh for the others – is plotted against diagonality. The diagonal lines show the distribution predicted for walking gaits by the revised support-pattern model. Compare Figs 3 and 11.Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 415, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
Figure 5 in Support polygons and symmetrical gaits in mammals
No full textFigure 5. Curves of unilateral bipedality (Bu) and diagonal bipedality (Bd) against diagonality (D) for the case where the duty factors of the hind- and forelimbs are equal (Sh = Sf = S). K = S − 50. All variables (Bu, Bd, D, K, S) represent durations expressed as percentages of the stride period (time between two successive falls of the same foot).Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 407, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
Figure 9 in Support polygons and symmetrical gaits in mammals
No full textFigure 9. Diagonality (D) plotted against the duty-factor index. The 100% line, along which Sf = Sh, represents the plane of the Hildebrand diagram, here seen edge-on. The diagonal black line is the bivariate least-squares regression line for all primate data (circles), excluding Callithrix (crosses). Black diamonds represent nonprimate data.Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 412, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
Figure 2 in Support polygons and symmetrical gaits in mammals
No full textFigure 2. Plot of diagonality against (average) duty factor: the Hildebrand diagram. Positions of some mammalian gait types (two-letter codes) are plotted on the diagram. DS, diagonal-sequence walks; LS, lateral-sequence walks; RP, running pace; RT, running trot; WP, walking pace; WT, walking trot.Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 403, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
Figure 1 in Support polygons and symmetrical gaits in mammals
No full textFigure 1. Quadrupedal gaits modelled as though being executed by two people in a horse costume. A, walking pace. The two bipeds are walking exactly in phase (diagonality = 0). B, running pace, shown during aerial phase (with all feet off the ground). The two bipeds are running in phase (diagonality = 0). C, running trot, shown during aerial phase. The two bipeds are running 180 ° out of phase; that is, the hind biped's cycle is running 50% of the cycle period ahead of the front biped's cycle (diagonality = 50). In a pace (A,B), both left feet (or both right feet) strike down together; in a trot (C), diagonally opposite feet strike down together. D, lateral-sequence (L-S) walk. The hind biped's cycle is running 25% of the cycle period ahead of the front biped's cycle (diagonality = 25%). E, diagonal-sequence (D-S) walk. The hind biped's cycle is running 75% of the cycle period ahead of the front biped's cycle (diagonality = 75%). In an L-S walk (D), the left hind footfall is followed by that of the left forefoot; in a D-S walk (E), it is followed by that of the right forefoot.Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 402, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
Osteoarthritis/degenerative joint disease
No full textOsteoarthritis (OA) or degenerative joint disease (DJD) is the most common disorder affecting the joints, affecting 10 percent of men and 18 percent of women over 60 years of age worldwide. OA results from the progressive breakdown of the articular cartilage and from a suite of degenerative and reactive patterns involving various tissues. Such patterns result in modifications of the joint architecture and of the joint segments which are variably visible radiologically and on dry bone. Due to its link with biomechanical stress, OA is studied extensively in paleopathology and bioarchaeology in order to reconstruct general and specific levels of physical activity in past populations. However, the etiological relevance of other factors besides physical activity (e.g. age, sex, and genetics) suggests the need for caution in such biocultural reconstructions, stressing at the same time the value of clinical studies for a better understanding of OA in bioarcheology and paleopathology
Figure 8 in Support polygons and symmetrical gaits in mammals
No full textFigure 8. Values of diagonality predicted from the support-polygon model. Duty factors and graphic conventions as in Figure 4. To minimize overall bipedality while maximizing diagonal bipedality ('2-diag'), a quadruped walking with a lateral-sequence gait (A) should adopt a Dvalue equal to 100 minus the forelimb duty factor (100 − Sf: horizontal arrows). A quadruped using a diagonal-sequence walk (B) should adopt a D-value equal to the hindlimb duty factor (Sh: horizontal arrows). In A, this entails that forefoot liftoffs and ipsilateral hind footfalls should be simultaneous; in B, fore footfalls and ipsilateral hindfoot liftoffs should be simultaneous (vertical arrows). In both A and B, diagonal bipedality ('2-diag') comprises the minimal percentage (64%) of the stride period possible for these duty factors. The animal is supported on 3 legs ('3-ped') for the remaining 36% of the stride period.Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 410, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
Figure 4 in Support polygons and symmetrical gaits in mammals
No full textFigure 4. Support patterns for two gait cycles with similar duty factors but different diagonalities. In each diagram, the horizontal axis represents time, expressed as a percentage of stride period. Horizontal black bars represent stance phase (period of ground contact) for each foot (LH, left hind; LF, left fore; RF, right fore; RH, right hind). Duty factors are 64 for hind feet and 54 for fore feet. Since the gait is symmetrical, LH and RH footfalls differ by exactly 50% of the cycle, as do LF and RF footfalls, and left and right duty factors are the same. Each cycle starts with the LH footfall. Diagonality (percentage of cycle by which LF footfall trails LH footfall) equals 26 in cycle A and 56 in cycle B. Hatched bars below each diagram show periods of different support patterns (by 2 feet on the same side, 2 diagonally opposite feet, 3 feet, and 4 feet) during each cycle. The lengths and timing of these periods can be inferred from the timing of the liftoff and touchdown of each foot (vertical dashed lines), which can in turn be inferred from duty factors and diagonality.Published as part of Cartmill, M., Lemelin, P. & Schmitt, D., 2002, Support polygons and symmetrical gaits in mammals, pp. 401-420 in Zoological Journal of the Linnean Society 136 (3) on page 406, DOI: 10.1046/j.1096-3642.2002.00038.x, http://zenodo.org/record/543690
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