BIOMECHANICAL MOVEMENT SYNERGIES - Biomechanics and Motor Control of Human Movement - page 281

11

BIOMECHANICAL MOVEMENT
SYNERGIES

11.0 INTRODUCTION

Because the neuro-mucsulo-skeletal system is so interconnected and inte-
grated, it is almost impossible to interpret the function of a single variable
at any single joint during the time course of any total body movement. The
various levels of integration were described in Section 1.2 where the first
three levels were involved with neuro-musculo integration to generate the
moment-of-force profile at a given joint. However, the reason for this final
motor profile is not evident until we look at the movement task to see how
the muscles at all joints contribute to the final goal. Also, during any given
movement an individual group of muscles may also have more than one
simultaneous subtask to accomplish.
Biomechanics has evolved as the major discipline that measures and anal-
yses the total body in 3D and, therefore, is capable of identifying total body
movement synergies either during normal everyday tasks or in response to
perturbations, either internal or external in origin. Some very quick examples
will be referenced to illustrate some of these total body analyses.

1. MacKinnon and Winter (1993) reported the total balance control in
the frontal plane during normal walking: the hip abductors responded
proactively to the gravitational and inertial forces acting on the HAT
segment to keep it nearly vertical during single support.
2. Eng et al., (1992) identified the total body responses to total arm volun-
tary movements in the sagittal plane: the hip, knee, and ankle moments