A Physiological Analysis of Walking in the American Lobster (Homarus americanus)

摘要: The normal, unrestrained, forward walking of the lobster was studied with a closed-circuit television system and video-tape recorder. A frame-by-frame analysis undertaken measurements made unilateral stepping sequences, contralateral ipsilateral phase relations between pairs legs, movements at leg joints primarily involved in their differences each four pereiopods. order expressed terms probability any following other it found that while there is preferred order, considerable variation from dominant pattern. commonest deviations gait are those involving simplest types re-ordering sequence. Pairs legs show strong tendency to alternate but all can occur. Similarly, relations, possible do pereiopods anterior posterior were have respectively, pulling action, combined rowing action pushing action. same parameters recorded animals on transparent, driven treadmill and, as no significant comparisons results freely moving animals, subsequent obtained where more detailed study manipulation could readily be made. third pereiopod during forwards involves major about two whereas move three joints. Detailed intra-leg activity therefore confined simpler considerably simplified problems collecting analysing data. Measurements angles swept out by movement. Electromyograms six muscles responsible for these movement transducers placed duration bursts interrelation different muscle measured computer-aided determine characteristic features inter-burst stepping. While variability step step, overall relatively phase-constant over wide range frequencies. When some key normal had been characterized, changes designed alter sensory input imposed. Changes power stroke return fractions cycle when animal induced pull or carry load. Because this result, series modifications applied unloaded animals. These included splinting abnormal angles, attaching prosthetic harnessing up off substrate partial total amputation. It phasing altered if support function impaired change direction which would compensate loss support. This result investigated further loading several ways so fraction loaded differentially. Comparisons demonstrated previously undescribed output response There marked reduction irrespective loaded, burst structure becomes highly constant most aspects. Other dependent load applied. significance results, particularly responses load, discussed context role walking.