Module $2$ Example Question

A motion analysis system was used to track markers placed on skin near the greater trochanter, the

lateral epicondyle of the femur, and the lateral malleoli of the ankle in the sagittal plane during the

stance phase of a fast walk. A using a $2$ link, $2$D model of the leg determine sum of the reaction forces

and moments in the knee and the hip at the instance given near the end of terminal stance. Position,

velocity, and acceleration of the markers, the center of pressure $($CoP$),$ ground reaction force $($GRF$),$ and

segment mass and inertia properties are given below.

Thigh Properties

Mass $=7kg$

CoG $=43\mathrm{.}3\%$ of the distance from H to K $.$

Rotational Inertial about CoG, $Ig=0\mathrm{.}066k{g}^{**}{m}^2$

Shank $+$ Foot Properties

Mass $=4\mathrm{.}3kg$

CoG$=60\mathrm{.}6\%$ of the distance from K to A $.$

Rotational Inertia about CoG, $Ig=0\mathrm{.}088k{g}^{**}{m}^2$

Hip Marker

$H=[396,653]mm$

$H^{}=[1086,-229]m\frac{m}{s}$

$H^{}=[1546,381]m\frac{m}{s^2}$

Knee Marker

$K=[327,364]mm$

$K^{}=[753,-211]m\frac{m}{s}$

$K^{}=[2481,632]m\frac{m}{s^2}$

Ankle Marker

$A=[134,80]mm$

$A^{}=[144,212]m\frac{m}{s}$

$A^{}=[1536,2235]m\frac{m}{s^2}$

CoP$=[310,0]mm$

$GRF=[201,874]N$