AbstractIn this paper, a ten-joint 3-D kinematic model has been developed by carefully st.udymg the anatomy of the lower limb during bicycling for understandmg and analyzmg the complex motions of the joints. An optimization algorithm has also been developed and used to compute the Joint vanables and find the numerical solution. In order to simulate the indeterminate kinematic system, random vectors of multinormal distribution have been generated and statistical means and variances have been obtained from these random vector samples. The validity of the developed model has been checked by comparing the results with that of experim.ental measurements. The model developed has good desirability to descnbe the hmb and IS more accurate than 2-D models to predict the motion of lower extremities.