THE MUSCULAR CONTROL OF VERTEBRATE SWIMMING MOVEMENTS
- 1 May 1977
- journal article
- Published by Wiley in Biological Reviews
- Vol. 52 (2) , 181-218
- https://doi.org/10.1111/j.1469-185x.1977.tb01349.x
Abstract
SUMMARY: The succession of hypotheses on the role of myotomal muscle in the generation of swimming movements is described and the conventional concept of ‘waves of contraction’ is shown to be based on a number of misinterpretations. The form of undulatory movements in vertebrate swimmers is characterized by the properties of the sinusoidal oscillation of parts of the body about the axis of progression. An important variable is the relative amplitude of the lateral oscillation of the head end, which can be large in some animals though usually small in most adult aquatic vertebrates. Cinematographic records of swimming animals are examined to determine the forces involved in the generation of waves of bending. A simplified analysis suggests that undulation can be produced by alternation of tension development from side to side without ‘waves of contraction’ passing down the body. Model systems which are able to flex from side to side are considered and two types distinguished ‐ the ‘resistance‐dominated’ which propagates waves of bending from centre to extremities, and the ‘stiffness‐dominated’ which does not. The type to which a model belongs is determined by the interrelationship of its stiffness and resistance, and the power with which it flexes. A model homogeneous in its properties along its length cannot generate longitudinal movement by flexing from side to side. Some degree of unevenness from one end to the other is required for propulsion. Observations of the movements of an ‘ostraciiform model’ are shown to discount previous theories of the hydromechanics of swimming by the oscillation of a stiff tail about a single pivot. A new interpretation is provided. The majority of vertebrate swimmers behave like ‘hybrid oscillators’ which flex from side to side, ‘resistance‐dominated’ posteriorly and ‘stiffness‐dominated’ anteriorly. The origin of the ‘waves of contraction’ suggested by electromyograms of swimming animals is traced to the requirement for a tail of variable stiffness for variable frequency of oscillation and to the need to reduce lateral oscillation of the head. Delayed contraction posteriorly and early contraction anteriorly contribute to these functions. The ability of amphioxus to swim backwards and the inability of most vertebrates to do so is related to their structural organization in the form of ‘hybrid oscillators’. Electromyograms are examined in the light of these mechanical models. A developmental sequence is described for the newt which illustrates the organization of the muscular control of swimming movements and may throw light upon the development of the neural mechanism.This publication has 35 references indexed in Scilit:
- Undulatory swimming with and without waves of contractionNature, 1976
- Central generation of locomotion in the spinal dogfishBrain Research, 1976
- Normal stages of development of the axolotl, Ambystoma mexicanumDevelopmental Biology, 1975
- Large-amplitude elongated-body theory of fish locomotionProceedings of the Royal Society of London. B. Biological Sciences, 1971
- SWIMMING AND THE ORIGIN OF PAIRED APPENDAGESAmerican Zoologist, 1962
- THE LATERAL MUSCULATURE AND THE SWIMMING OF FISHJournal of Zoology, 1956
- Erregungsbildung und Erregungsleitung im FischrückenmarkPflügers Archiv - European Journal of Physiology, 1935
- Directional control of fish movementProceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character, 1933
- The development of reflex mechanisms in amblystomaJournal of Comparative Neurology, 1915
- CHANGES IN THE BEHAVIOR OF THE EEL DURING TRANSFORMTIONAnnals of the New York Academy of Sciences, 1912