Metabolic Costs Of Generating Force :: essays research papers

ENERGETCS OF BIPEDAL path1. METABOLIC COST OF GENERATING FORCESummarySimilarly sized bipeds and quadrupeds white plague nearly the same amount of metabolic energy to run, despite striking differences in morphology and running chemical mechanism. It has been shown that the send of metabolic energy make riding habit of in quadrupedal runners and biped hoppers piece of ass be predicted from just corpse weight and time available to gene judge issue as indicated by the foot ground contact. We tested whether this link between running mechanics and energetics also applied to running bipeds. We measured rates of energy ingestion and times of foot contact for humans (mean body mass 78.88kg) and quintuple species of bird mean body mass 0.13-40.1 kg). We find that most (70-90%) of the accession in metabolic rate with speed in running bipeds can be explained by changes in the time available to generate force. The rate of force contemporaries also explains differences in metabolic rate everyplace the size range of birds measured. However, for a attached rate of force generation, birds utilise on average 1.7 times more metabolic energy than quadrupeds. The rate of energy consumption for a given rate of force generation for humans is intermediate between that of birds and quadrupeds. These results arrest the idea that the costs of stringy force production determines the energy cost of running and suggest that bipedal runners use more energy for a given rate of force production because they require a greater volume of muscle to support their body weight.Key words locomotion, energetics, bipedal, bird, muscle force.IntroductionThe question of flinch more energy is required to run on two or four legs was addressed 100 years ago when Zuntz (1897) performed some of the number 1 measurements of metabolic energy consumption in running animals. He embed that horses used less energy than humans to move a social unit body weight a unit distance, and he specula ted that there office be an energetic benefit to moving on four legs quite an than two. However, subsequent measurements of oxygen consumption in running dogs showed that these quadrupeds use more energy per unit body mass to move a given distance than both humans and horses.Zuntz (1987) noticed that this energy cost of trance in horses, dogs and humans was proportional not to limb number only to body mass and concluded that, per unit body weight, small animals use more energy to run a given distance than do large animals, regardless of limb number (Zuntz, 1987).