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Biological Mechanisms as Models
for Mimicking: Sarcomere Design,
Arrangement and Muscle Function

Kenneth Meijer, Juan C. Moreno, and Hans H.C.M. Savelberg

CONTENTS
2.1 Introduction ............................................................................................................................................ 41
2.2 Muscle Function..................................................................................................................................... 43
2.3 The Functional Units.............................................................................................................................. 44
2.3.1 The Sarcomere .......................................................................................................................... 45
2.4 Muscle Design........................................................................................................................................ 47
2.4.1 Not all Sarcomeres Are Alike...................................................................................................47
2.4.2 Rearranging the Sarcomeres, Muscle Morphology.................................................................. 49
2.5 Muscle Adaptation ................................................................................................................................. 50
2.6 Biomimetics of Muscle Design.............................................................................................................. 51
2.7 Summary ................................................................................................................................................ 53
References......................................................................................................................................................... 53

2.1 INTRODUCTION

We marvel at the extraordinary performances of animals. The animal kingdom provides us with
inspiring examples of species that move seemingly effortless in unstructured, unpredictable,
and ever-changing environments. To appreciate the beauty and the complexity of the motion
of animals, one just has to think of a gazelle trying to escape a cheetah on the Serengeti
plains. Both animals display a remarkable maneuverability, while running at maximum speed over
a bumpy terrain covered by obstacles. Their performance is shaped by their evolution driven by
the need to outperform the other in the struggle for survival. Their abilities outdo that of any human-
made device and it is not surprising that humans have tried to develop devices that mimic animal
locomotion.
As far back as the 15th century people have designed and built machines in an effort to copy
aspects of animal locomotion (Breazeal and Bar-Cohen, 2003). The resulting designs were great
illustrations of the technological ‘‘state of the art’’ of those times. None of these designs, however,
yielded performances that came close to mimicking the agility and performance of biological
locomotion. The most likely explanation for this is that those devices were engineered using
materials with very different properties compared to biological materials. Only recently, with the

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