Thomas Aquinas McMahon

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Trotting and hopping animals use muscles, tendons and ligaments to store and return elastic energy as they bounce along the ground. We examine how the musculoskeletal spring system operates at different speeds and in animals of different sizes. We model trotting and hopping as a simple spring-mass system which consists of a leg spring and a mass. We find(More)
Using a linear mass-spring model of the body and leg (T. A. McMahon and G. C. Cheng. J. Biomech. 23: 65-78, 1990), we present experimental observations of human running under simulated low gravity and an analysis of these experiments. The purpose of the study was to investigate how the spring properties of the leg are adjusted to different levels of(More)
The Huxley 1957 model of cross-bridge cycling accounts for the shortening force-velocity curve of striated muscle with great precision. For forced lengthening, however, the model diverges from experimental results. This paper examines whether it is possible to bring the model into better agreement with experiments, and if so what must be assumed about the(More)
Many parameters of gait and performance, including stride frequency, stride length, maximum speed, and rate of O2 uptake are experimentally found to be power-law functions of body weight in running quadrupeds. All of these parameters are reasonably easy to measure except maximum speed, where the question arises whether one means top sprinting speed or top(More)
Hymenoptera attach to smooth surfaces with a flexible pad, the arolium, between the claws. Here we investigate its movement in Asian weaver ants (Oecophylla smaragdina) and honeybees (Apis mellifera). When ants run upside down on a smooth surface, the arolium is unfolded and folded back with each step. Its extension is strictly coupled with the retraction(More)
Fall dynamics have largely been ignored in the study of hip fracture etiology and in the development of hip fracture prevention strategies. In this study, we asked the following questions: (1) What are the ranges of hip impact velocities associated with a sideways fall from standing height? (2) What are the ranges of body configurations at impact? and (3)(More)
The running gaits used by both bipedal and quadrupedal animals are reviewed and contrasted. At high speeds, bipeds use both ordinary running, in which the legs move opposite one another, and hopping. Quadrupeds generally use the trot or its variations at moderate speeds, and first the canter and then the gallop as speed increases. Running in both bipeds and(More)