- T Xl A Find The X And Y Coordinates Of The Center Of Mass Of The Foot And Leg Use Table 3 1 63 B Find The X And Y V 1 (41.07 KiB) Viewed 40 times
- T Xl A Find The X And Y Coordinates Of The Center Of Mass Of The Foot And Leg Use Table 3 1 63 B Find The X And Y V 2 (23.95 KiB) Viewed 40 times
- T Xl A Find The X And Y Coordinates Of The Center Of Mass Of The Foot And Leg Use Table 3 1 63 B Find The X And Y V 3 (52.5 KiB) Viewed 40 times
- T Xl A Find The X And Y Coordinates Of The Center Of Mass Of The Foot And Leg Use Table 3 1 63 B Find The X And Y V 4 (68.73 KiB) Viewed 40 times
C) Find the length of the Leg (femoral condyles/medial malleolus) from the table above, and use Table 3.1.163 to find the height of the subject. D) If the mass of the subject is 80 kg, find the mass of the Foot and Leg and its moment of inertia about its center of mus (use Table 3.1/63).
50 Chapter 2 Loads and Motion in the Musculoskeletal System FIGURE 2.11 Average seg ment lengths as a function of height (Figure 3.1 from Winter, D.A, Biomechanic and Motor Control of Human Movement. Wiley Interscience, New York, 1990.) O 0.936- 0.870H 0.816 0.630H- 0.405H 1377H ⠀ -0.174H -0.191H- 0.055H Foot breadth 0.130H 1854-01454- 1+0.1524- Foot leng 0.299 0.720H 0530 0.108 0.520M Mathematical models for mass properties By assuming that the major body segments correspond roughly to some common shapes, standard formalac for simple shapes can be combined with anatomical measurements and known density information to predict mass properties. Various models have been proposed that use ellipsoids, truncated cones, or ellipsoidal cylinders (Figure 2.12). Estimates of individual segment parameters can be obtained from estimates average density and measured lengths and diameters. Obviously, the model could a refined by defining more complex solid shapes to model the segments. For example truncated ellipsoidal cones, instead of truncated circular cones, could be used for the limb segments. For the trunk segments, an alternative is to use a composite volume, such as a stadium solid, defined as a solid with cross sections composed of rectangles completed with semicircles on each end. The mathematical approach represents a sig nificant idealization, but it can easily be programmed, and it can-readily handle three-dimensional problems, whereas most of the experimental data is limited to the sagittal plane. EXAMPLE 2.6 Question Cons who is riding in a initial angular acc Solution To sol hip, and the entire a single unit. A fre We will also resaltant forces ac to internal forces This means that th me for conven the hip jount center then use the previc only unknown will egment parameter With the afo about the hip joint The hip joint acceleration of the
explicit appearance of unknown P is fixed (not moving) at the P and the foregoing equa point eem. Besides the cases for the at there is a third situation where simple form, specifically when bottom line of this discussion is che musculoskeletal system, you te the moment equation about a uation is more complicated than on the body is used as the refer and Geometric Properties mical properties to be specified for clude the masses of the segments or quasi-static problem. Dynamics for the segments. If muscle forces geomlemic parameters describing on are often described by locating nt. In order to arrive at useful pa cal data alone, or on empirical in amber of investigators have meas es or cadavers. Mass distribution ters, and mass moments of iner- have been used to develop empir meters for a given subject on the ght and height. Table 2.3 was a m various studies. o know segment lengths. Some av by Drillis and Contini and are su verages from small populations of ure describing various attempts to the data for individual subjects. se numbers, there is a reasonable model have a corresponding level of iomechanics models). If you are hing to do is to get answers for se w much the uncertainties can affect TABLE 2.3 Anthropometric Data Segment Hand Form Upper am Fonem and hand Toralarm Foot Leg Foot and leg Tocal leg Head and neck Shoulder Thorax Abdomen Pelvis Thox Wrist axiscle middle finger bow axilar styloid Glohamal bow Chow axilid Gimurallar styloid Lateral malled maal Femoral condylesdial malleolus Greater troch femoral condyles Femoral condylemedial maleoha Gestertrochass medial malleus C7-11 and str car canal Soclavicular jo lemobumelacia C7-T1/T12-L1 and diaphrag T12-LA-LS L-Sigra trochanter (7-7144-L5* abdomen Abdon T12-L1 and pelvis Track trochanter Greater crochaste Trnk BAT glenohumeral joi Greater trochanted brad onck glenohumeral join Greaser trochas glenohumeral join Greater trochante HAT Segment Weigh Total Body Weghs 0.006 M 0.016 M 0.028 M 0.022 M 0.050 M 0.0145 M 00465 M 0.100 M 0.061 M 0.161 M 0.081 M 0216 PC 0.139 LC 0.142LC 0.355 LC 0.281 PC 0.497 M 0.578 MC 0678 MC 0.678 Section 2.3 The Metal Dynamic Problem Center of Mal Segm Length 0494 P 0297 0.587 1.16 Proxinal Dial ColG Provinal Dial Density 0.506 0.577 M 0.430 0.570P 0.303 0.536 0.436 0.5647 0.322 0.542 0.482 0318 0.468 0.827 0.565P 0.645 0.3967 0.530 0470 0.368 0.490 DAYOP G475 0.5677 0.302 0.528 0.433 0.433 05677 0.323 0.540 0.606 0347 0.416 0.735 0.447 0553 P 0.336 0.560 -PC 0.495 1.116 1.000 0.712 02 0.50 0.507 0.18 0.44 0.56 0.105 0.395 0.63 6.37 0.27 0.50 0.66 0.626 1.142 0.73 0.50 1 Radion of Ceration Segment Length 034P 0.303 0.374 PC 0.496 9.647 M 1.13 0.645M 2.07 1.14 1.11 1.30 1.29 1.05 0.903 1.456 0.643 M 0.653 M 0.572 P 0.650 P <-I 1 0.830 06074 4.795 0421 PC 1.09 1.06 LII 1.04 0.92 = I 1.01 1.03 NOTE These are pro relacive to the length been de gater cher and the global in S Table 3.11 WDA, Rics and Motor Control of Human Mount Wy , New York, 1990 JM Demper via Miler and Neon Bochnics of Sport, Les and Feign Phid, 1973. 2 pria Pop of Hun Motion Pice-Hall, Eaglewood C, NJ, 1971. L, Dari Ping Mai, Precice Hall, , Engiwood C, NJ, 1971. C Ca Pf