Optimization and Systems Theory Seminar
Friday, March 13, 1998, 11.00-12.00, Room 3721, Lindstedtsvägen 25

Yssa DeWoody
Department of Mathematics,
Texas Tech. University,
Lubbock, Texas, USA

A direct approach utilizing musculoskeletal dynamics and neuromuscular control to determine stress development in bone

The role of forces produced by the musculotendon units in the stress development of the long bones during gait has not been fully analyzed. It is well known that the musculotendons act as actuators producing the joint torques which drive the body. Although the joint torques required to perform certain motor tasks can be recovered through a kinematic analysis, it remains a difficult problem to determine the actual forces produced by each muscle that resulted in these torques. As a consequence, few studies have focused on the role of individual muscles in the development of stress in the bone.

This study takes a control theoretic approach to the problem. A seven link, eight DOF model of the body is controlled by various muscle groups on each leg to simulate gait. The simulations incorporate Hill-type models of muscles with activation and contraction dynamics controlled through neural inputs. This direct approach allows one to know the exact muscle forces exerted by each musculotendon throughout the gait cycle as well the joint torques and reaction forces at the ankle and knee. Stress and strain computed by finite element analysis on skeletal members will be related to these derived loading conditions. Thus the role of musculoskeletal dynamics and neuromuscular control in the stress development of the tibia during gait can be analyzed.

Calendar of seminars
Last update: March 5, 1998 by Anders Forsgren, andersf@math.kth.se.