The effect of lower limb length on the energetic cost of locomotion: implications for fossil hominins

2004 ◽  
Vol 47 (1-2) ◽  
pp. 95-109 ◽  
Author(s):  
K STEUDELNUMBERS
Keyword(s):  
Lower Limb ◽  
Limb Length ◽  
Energetic Cost ◽  
Cost Of Locomotion ◽  
Fossil Hominins

scholarly journals Limitations imposed by wearing armour on Medieval soldiers' locomotor performance

2011 ◽  
Vol 279 (1729) ◽  
pp. 640-644 ◽  
Author(s):  
Graham N. Askew ◽  
Federico Formenti ◽  
Alberto E. Minetti
Keyword(s):  
Fifteenth Century ◽  
Physical Performance ◽  
Energy Use ◽  
Steel Plate ◽  
Energetic Cost ◽  
Entire Body ◽  
Additional Mass ◽  
Medieval Europe ◽  
Cost Of Locomotion ◽  
Locomotor Energetics

In Medieval Europe, soldiers wore steel plate armour for protection during warfare. Armour design reflected a trade-off between protection and mobility it offered the wearer. By the fifteenth century, a typical suit of field armour weighed between 30 and 50 kg and was distributed over the entire body. How much wearing armour affected Medieval soldiers' locomotor energetics and biomechanics is unknown. We investigated the mechanics and the energetic cost of locomotion in armour, and determined the effects on physical performance. We found that the net cost of locomotion ( C met ) during armoured walking and running is much more energetically expensive than unloaded locomotion. C met for locomotion in armour was 2.1–2.3 times higher for walking, and 1.9 times higher for running when compared with C met for unloaded locomotion at the same speed. An important component of the increased energy use results from the extra force that must be generated to support the additional mass. However, the energetic cost of locomotion in armour was also much higher than equivalent trunk loading. This additional cost is mostly explained by the increased energy required to swing the limbs and impaired breathing. Our findings can predict age-associated decline in Medieval soldiers' physical performance, and have potential implications in understanding the outcomes of past European military battles.

Speed, stride frequency and energy cost per stride: how do they change with body size and gait?

1988 ◽  
Vol 138 (1) ◽  
pp. 301-318 ◽  
Author(s):  
N. C. Heglund ◽  
C. R. Taylor
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Energy Cost ◽  
Reaction Force ◽  
Stride Frequency ◽  
Energetic Cost ◽  
Published Data ◽  
Frequency Change ◽  
Cost Of Locomotion ◽  
The Cost

In this study we investigate how speed and stride frequency change with body size. We use this information to define ‘equivalent speeds’ for animals of different size and to explore the factors underlying the six-fold difference in mass-specific energy cost of locomotion between mouse- and horse-sized animals at these speeds. Speeds and stride frequencies within a trot and a gallop were measured on a treadmill in 16 species of wild and domestic quadrupeds, ranging in body size from 30 g mice to 200 kg horses. We found that the minimum, preferred and maximum sustained speeds within a trot and a gallop all change in the same rather dramatic manner with body size, differing by nine-fold between mice and horses (i.e. all three speeds scale with about the 0.2 power of body mass). Although the absolute speeds differ greatly, the maximum sustainable speed was about 2.6-fold greater than the minimum within a trot, and 2.1-fold greater within a gallop. The frequencies used to sustain the equivalent speeds (with the exception of the minimum trotting speed) scale with about the same factor, the −0.15 power of body mass. Combining this speed and frequency data with previously published data on the energetic cost of locomotion, we find that the mass-specific energetic cost of locomotion is almost directly proportional to the stride frequency used to sustain a constant speed at all the equivalent speeds within a trot and a gallop, except for the minimum trotting speed (where it changes by a factor of two over the size range of animals studied). Thus the energy cost per kilogram per stride at five of the six equivalent speeds is about the same for all animals, independent of body size, but increases with speed: 5.0 J kg-1 stride-1 at the preferred trotting speed; 5.3 J kg-1 stride-1 at the trot-gallop transition speed; 7.5 J kg-1 stride-1 at the preferred galloping speed; and 9.4 J kg-1 stride-1 at the maximum sustained galloping speed. The cost of locomotion is determined primarily by the cost of activating muscles and of generating a unit of force for a unit of time. Our data show that both these costs increase directly with the stride frequency used at equivalent speeds by different-sized animals. The increase in cost per stride with muscles (necessitating higher muscle forces for the same ground reaction force) as stride length increases both in the trot and in the gallop.

Moving cheaply: energetics of walking in the African elephant.

1995 ◽  
Vol 198 (3) ◽  
pp. 629-632 ◽  
Author(s):  
V A Langman ◽  
T J Roberts ◽  
J Black ◽  
G M Maloiy ◽  
N C Heglund ◽  
...  
Keyword(s):  
Fuel Economy ◽  
African Elephant ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Allometric Relationships ◽  
Cost Of Locomotion ◽  
Biological Laws ◽  
Large Animals ◽  
The Cost

Large animals have a much better fuel economy than small ones, both when they rest and when they run. At rest, each gram of tissue of the largest land animal, the African elephant, consumes metabolic energy at 1/20 the rate of a mouse; using existing allometric relationships, we calculate that it should be able to carry 1 g of its tissue (or a load) for 1 km at 1/40 the cost for a mouse. These relationships between energetics and size are so consistent that they have been characterized as biological laws. The elephant has massive legs and lumbers along awkwardly, suggesting that it might expend more energy to move about than other animals. We find, however, that its energetic cost of locomotion is predicted remarkably well by the allometric relationships and is the lowest recorded for any living land animal.

scholarly journals Muscle forces and the demands of human walking

Biology Open ◽  
2021 ◽  
Vol 10 (7) ◽  
Author(s):  
Adam D. Sylvester ◽  
Steven G. Lautzenheiser ◽  
Patricia Ann Kramer
Keyword(s):  
Lower Limb ◽  
Reaction Force ◽  
The Body ◽  
Muscle Forces ◽  
Skeletal Morphology ◽  
Lower Limb Muscles ◽  
Fossil Hominins ◽  
Force Curves ◽  
Behavior Function ◽  
The Relationship

ABSTRACT Reconstructing the locomotor behavior of extinct animals depends on elucidating the principles that link behavior, function, and morphology, which can only be done using extant animals. Within the human lineage, the evolution of bipedalism represents a critical transition, and evaluating fossil hominins depends on understanding the relationship between lower limb forces and skeletal morphology in living humans. As a step toward that goal, here we use a musculoskeletal model to estimate forces in the lower limb muscles of ten individuals during walking. The purpose is to quantify the consistency, timing, and magnitude of these muscle forces during the stance phase of walking. We find that muscles which act to support or propel the body during walking demonstrate the greatest force magnitudes as well as the highest consistency in the shape of force curves among individuals. Muscles that generate moments in the same direction as, or orthogonal to, the ground reaction force show lower forces of greater variability. These data can be used to define the envelope of load cases that need to be examined in order to understand human lower limb skeletal load bearing.

Armed forces: Intrasexual selection for upper limb length in Homo sapiens

2021 ◽  
Author(s):  
Neil Robert Caton ◽  
David M. G. Lewis
Keyword(s):  
Sexual Dimorphism ◽  
Upper Limb ◽  
Real World ◽  
Lower Limb ◽  
Homo Sapiens ◽  
Armed Forces ◽  
Outcome Data ◽  
Resource Provisioning ◽  
Limb Length ◽  
Intrasexual Selection

Numerous taxa have evolved physiological appendage-based weaponry to increase damage output in violent fights, but no research has empirically shown that Homo sapiens upper appendages have uniquely evolved to increase resource-provisioning potential in real-world combat. In Study 1, we used actual fight outcome data (N = 715 fighters) to examine multiple competing hypotheses—the striker, defender, grappler, and knockout hypotheses—for the evolution of Homo sapiens upper limb length, controlling for approximately a dozen confounding variables (e.g., biacromial width, lower limb length, age, weight, height). There was exclusive support for the knockout hypothesis: upper limb length increases fighting success through knockout power. There was also evidence for a real-world association between biacromial width and knockout power. Because sexual dimorphism often emerges from selection on morphological structures that improve male’s fighting success, we consequently expected sexual dimorphism in upper limb length. Studies 2a-2d provided powerful evidence for this new universal sexual dimorphism in upper limb length. Even after controlling for weight, height, and lower limb length, males exhibited longer upper limbs than females across the globe: from mixed-martial-artists (Study 2a) and Croatian adolescents (but not pre-pubertal children; Study 2b) to older Singaporean adults (Study 2c) and over 6,000 United States Army personnel (Study 2d) born across seven major world regions (Africa, Europe, Asia, Oceania, and North, Central, and South America). Combined, our results provide comprehensive support for the argument that intrasexual selection has uniquely shaped Homo sapiens upper limb length to enhance fighting performance in real-world combat.

Efficiency of uphill locomotion in nocturnal and diurnal lizards

1996 ◽  
Vol 199 (3) ◽  
pp. 587-592 ◽  
Author(s):  
C Farley ◽  
M Emshwiller
Keyword(s):  
Body Mass ◽  
Low Cost ◽  
Minimum Cost ◽  
Mechanical Work ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Unit Distance ◽  
Cost Of Locomotion ◽  
Average Body Mass ◽  
Average Body

Nocturnal geckos can walk on level ground more economically than diurnal lizards. One hypothesis for why nocturnal geckos have a low cost of locomotion is that they can perform mechanical work during locomotion more efficiently than other lizards. To test this hypothesis, we compared the efficiency of the nocturnal gecko Coleonyx variegatus (average body mass 4.2 g) and the diurnal skink Eumeces skiltonianus (average body mass 4.8 g) when they performed vertical work during uphill locomotion. We measured the rate of oxygen consumption when each species walked on the level and up a 50 slope over a range of speeds. For Coleonyx variegatus, the energetic cost of traveling a unit distance (the minimum cost of transport, Cmin) increased from 1.5 to 2.7 ml O2 kg-1 m-1 between level and uphill locomotion. For Eumeces skiltonianus, Cmin increased from 2.5 to 4.7 ml O2 kg-1 m-1 between level and uphill locomotion. By taking the difference between Cmin for level and uphill locomotion, we found that the efficiency of performing vertical work during locomotion was 37 % for Coleonyx variegatus and 19 % for Eumeces skiltonianus. The similarity between the 1.9-fold difference in vertical efficiency and the 1.7-fold difference in the cost of transport on level ground is consistent with the hypothesis that nocturnal geckos have a lower cost of locomotion than other lizards because they can perform mechanical work during locomotion more efficiently.

Energetic cost of locomotion in the tammar wallaby

1992 ◽  
Vol 262 (5) ◽  
pp. R771-R778 ◽  
Author(s):  
R. V. Baudinette ◽  
G. K. Snyder ◽  
P. B. Frappell
Keyword(s):  
Oxygen Consumption ◽  
Blood Lactate ◽  
Body Mass ◽  
Energy Cost ◽  
Physiological Adaptation ◽  
Energetic Cost ◽  
Cost Of Locomotion ◽  
Lactate Levels ◽  
Energy Cost Of Locomotion ◽  
Blood Lactate Levels

Rates of oxygen consumption and blood lactate levels were measured in tammar wallabies (Macropus eugenii) trained to hop on a treadmill. In addition, the work required to overcome wind resistance during forward locomotion was measured in a wind tunnel. Up to approximately 2.0 m/s, rates of oxygen consumption increased linearly with speed and were not significantly different from rates of oxygen consumption for a quadruped of similar body mass. Between 2.0 and 9.4 m/s, rates of oxygen consumption were independent of hopping speed, and between 3.9 and 7.9 m/s, the range over which samples were obtained, blood lactate levels were low (0.83 +/- 0.13 mmol.min-1.kg-1) and did not increase with hopping speed. The work necessary to overcome drag increased exponentially with speed but increased the energy cost of locomotion by only 10% at the average speed attained by our fast hoppers. Thus, during hopping, the energy cost of locomotion is effectively independent of speed. At rates of travel observed in the field, the estimated energy cost of transport in large macropods is less than one-third the cost for a quadruped of equivalent body mass. The energetic savings associated with this unique form of locomotion may have been an important physiological adaptation, enabling large macropods to efficiently cover the distances necessary to forage in the semiarid landscapes of Australia.

scholarly journals The mechanics and energetics of human walking and running: a joint level perspective

2011 ◽  
Vol 9 (66) ◽  
pp. 110-118 ◽  
Author(s):  
Dominic James Farris ◽  
Gregory S. Sawicki
Keyword(s):  
Power Output ◽  
Lower Limb ◽  
Metabolic Cost ◽  
Mechanical Work ◽  
Total Power ◽  
Joint Mechanics ◽  
Metabolic Power ◽  
Cost Of Transport ◽  
Cost Of Locomotion ◽  
Shed Light

Humans walk and run at a range of speeds. While steady locomotion at a given speed requires no net mechanical work, moving faster does demand both more positive and negative mechanical work per stride. Is this increased demand met by increasing power output at all lower limb joints or just some of them? Does running rely on different joints for power output than walking? How does this contribute to the metabolic cost of locomotion? This study examined the effects of walking and running speed on lower limb joint mechanics and metabolic cost of transport in humans. Kinematic and kinetic data for 10 participants were collected for a range of walking (0.75, 1.25, 1.75, 2.0 m s −1 ) and running (2.0, 2.25, 2.75, 3.25 m s −1 ) speeds. Net metabolic power was measured by indirect calorimetry. Within each gait, there was no difference in the proportion of power contributed by each joint (hip, knee, ankle) to total power across speeds. Changing from walking to running resulted in a significant ( p = 0.02) shift in power production from the hip to the ankle which may explain the higher efficiency of running at speeds above 2.0 m s −1 and shed light on a potential mechanism behind the walk–run transition.

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