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Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power (2020)
Journal Article
Usherwood, J. R., & Gladman, N. W. (2020). Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power. Biology Letters, 16(10), 20200579

The fastest land animals are of intermediate size. Cheetah, antelope, greyhounds and racehorses have been measured running much faster than reported for elephants or elephant shrews. Can this be attributed to scaling of physical demands and explicit... Read More about Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power.

Artificial mass loading disrupts stable social order in pigeon dominance hierarchies (2020)
Journal Article
Portugal, S. J., Usherwood, J. R., White, C. R., Sankey, D. W. E., & Wilson, A. M. (2020). Artificial mass loading disrupts stable social order in pigeon dominance hierarchies. Biology Letters, 16(8), 20200468

Dominance hierarchies confer benefits to group members by decreasing the incidences of physical conflict, but may result in certain lower ranked individuals consistently missing out on access to resources. Here, we report a linear dominance hierarchy... Read More about Artificial mass loading disrupts stable social order in pigeon dominance hierarchies.

The Possibility of Zero Limb-Work Gaits in Sprawled and Parasagittal Quadrupeds: Insights from Linkages of the Industrial Revolution (2020)
Journal Article
Usherwood, J. R. (2020). The Possibility of Zero Limb-Work Gaits in Sprawled and Parasagittal Quadrupeds: Insights from Linkages of the Industrial Revolution. Integrative Organismal Biology, 2(1),

Animal legs are diverse, complex, and perform many roles. One defining requirement of legs is to facilitate terrestrial travel with some degree of economy. This could, theoretically, be achieved without loss of mechanical energy if the body could tak... Read More about The Possibility of Zero Limb-Work Gaits in Sprawled and Parasagittal Quadrupeds: Insights from Linkages of the Industrial Revolution.

High aerodynamic lift from the tail reduces drag in gliding raptors (2020)
Journal Article
Usherwood, J. R., Cheney, J. A., Song, J., Windsor, S. P., Stevenson, J. P. J., Dierksheide, U., Nila, A., & Bomphrey, R. J. (2020). High aerodynamic lift from the tail reduces drag in gliding raptors. Journal of Experimental Biology, 223, https://doi.org/10.1242/jeb.214809

Many functions have been postulated for the aerodynamic role of the avian tail during steady-state flight. By analogy with conventional aircraft, the tail might provide passive pitch stability if it produced very low or negative lift. Alternatively,... Read More about High aerodynamic lift from the tail reduces drag in gliding raptors.

Minimalist analogue robot discovers animal-like walking gaits (2019)
Journal Article
Smith, B. J. H., & Usherwood, J. R. (2019). Minimalist analogue robot discovers animal-like walking gaits. https://doi.org/10.1088/1748-3190/ab654e

Robots based on simplified or abstracted biomechanical concepts can be a useful tool for investigating how and why animals move the way they do. In this paper we present an extremely simple quadruped robot, which is able to walk with no form of softw... Read More about Minimalist analogue robot discovers animal-like walking gaits.

The scaling or ontogeny of human gait kinetics and walk-run transition: The implications of work vs. peak power minimization (2018)
Journal Article
Usherwood, J. R., Hubel, T. Y., Smith, B. J. H., Self Davies, Z. T., & Sobota, G. (2018). The scaling or ontogeny of human gait kinetics and walk-run transition: The implications of work vs. peak power minimization. Journal of Biomechanics, 81, 12-21. https://doi.org/10.1016/j.jbiomech.2018.09.004

A simple model is developed to find vertical force profiles and stance durations that minimize either limb mechanical work or peak power demands during bipedal locomotion. The model predicts that work minimization is achieved with a symmetrical verti... Read More about The scaling or ontogeny of human gait kinetics and walk-run transition: The implications of work vs. peak power minimization.

The grazing gait, and implications of toppling table geometry for primate footfall sequences (2018)
Journal Article
Usherwood, J. R., & Smith, B. J. H. (2018). The grazing gait, and implications of toppling table geometry for primate footfall sequences. Biology Letters, 14(5), https://doi.org/10.1098/rsbl.2018.0137

Many medium and large herbivores locomote forwards very slowly and intermittently when grazing. While the footfall order during grazing is the same as for walking, the relative fore–hind timing—phasing—is quite different. Extended periods of static s... Read More about The grazing gait, and implications of toppling table geometry for primate footfall sequences.

Work minimization accounts for footfall phasing in slow quadrupedal gaits (2017)
Journal Article
Usherwood, J. R., & Self Davies, Z. T. (2017). Work minimization accounts for footfall phasing in slow quadrupedal gaits. eLife, 6, e29495. https://doi.org/10.7554/eLife.29495.001

Quadrupeds, like most bipeds, tend to walk with an even left/right footfall timing. However, the phasing between hind and forelimbs shows considerable variation. Here, we account for this variation by modeling and explaining the influence of hind-for... Read More about Work minimization accounts for footfall phasing in slow quadrupedal gaits.

Physiological, aerodynamic and geometric constraints of flapping account for bird gaits, and bounding and flap-gliding flight strategies (2016)
Journal Article
Usherwood, J. R. (2016). Physiological, aerodynamic and geometric constraints of flapping account for bird gaits, and bounding and flap-gliding flight strategies. Journal of Theoretical Biology, 408, 42-52. https://doi.org/10.1016/j.jtbi.2016.07.003

Aerodynamically economical flight is steady and level. The high-amplitude flapping and bounding flight style of many small birds departs considerably from any aerodynamic or purely mechanical optimum. Further, many large birds adopt a flap-glide flig... Read More about Physiological, aerodynamic and geometric constraints of flapping account for bird gaits, and bounding and flap-gliding flight strategies.

Social density processes regulate the functioning and performance of foraging human teams (2015)
Journal Article
King, A. J., Myatt, J. P., Fuertbauer, I., Oesch, N., Dunbar, R. I. M., Sumner, S., Usherwood, J. R., Hailes, S., & Brown, M. R. (2015). Social density processes regulate the functioning and performance of foraging human teams. https://doi.org/10.1038/srep18260

Social density processes impact the activity and order of collective behaviours in a variety of biological systems. Much effort has been devoted to understanding how density of people affects collective human motion in the context of pedestrian flows... Read More about Social density processes regulate the functioning and performance of foraging human teams.

Children and adults minimise activated muscle volume by selecting gait parameters that balance gross mechanical power and work demands (2015)
Journal Article
Hubel, T. Y., & Usherwood, J. R. (2015). Children and adults minimise activated muscle volume by selecting gait parameters that balance gross mechanical power and work demands. Journal of Experimental Biology, 218(PT 18), 2830-2839. https://doi.org/10.1242/jeb.122135

Terrestrial locomotion on legs is energetically expensive. Compared with cycling, or with locomotion in swimming or flying animals, walking and running are highly uneconomical. Legged gaits that minimise mechanical work have previously been identifie... Read More about Children and adults minimise activated muscle volume by selecting gait parameters that balance gross mechanical power and work demands.

Identification of mouse gaits using a novel force-sensing exercise wheel (2015)
Journal Article
Smith, B. J. H., Cullingford, L., & Usherwood, J. R. (2015). Identification of mouse gaits using a novel force-sensing exercise wheel. Journal of Applied Physiology, 119(6), 704-718. https://doi.org/10.1152/japplphysiol.01014.2014

The gaits that animals use can provide information on neurological and musculoskeletal disorders, as well as the biomechanics of locomotion. Mice are a common research model in many fields; however, there is no consensus in the literature on how (and... Read More about Identification of mouse gaits using a novel force-sensing exercise wheel.

Matching times of leading and following suggest cooperation through direct reciprocity during V-formation flight in ibis (2015)
Journal Article
Voelkl, B., Portugal, S. J., Unsoeld, M., Usherwood, J. R., Wilson, A. M., & Fritz, J. (2015). Matching times of leading and following suggest cooperation through direct reciprocity during V-formation flight in ibis. https://doi.org/10.1073/pnas.1413589112

One conspicuous feature of several larger bird species is their annual migration in V-shaped or echelon formation. When birds are flying in these formations, energy savings can be achieved by using the aerodynamic up-wash produced by the preceding bi... Read More about Matching times of leading and following suggest cooperation through direct reciprocity during V-formation flight in ibis.

Upwash exploitation and downwash avoidance by flap phasing in ibis formation flight (2014)
Journal Article
Portugal, S. J., Hubel, T. Y., Fritz, J., Heese, S., Trobe, D., Voelkl, B., Hailes, S., Wilson, A. M., & Usherwood, J. R. (2014). Upwash exploitation and downwash avoidance by flap phasing in ibis formation flight. Nature, 505(7483), 399-+. https://doi.org/10.1038/nature12939

Many species travel in highly organized groups. The most quoted function of these configurations is to reduce energy expenditure and enhance locomotor performance of individuals in the assemblage. The distinctive V formation of bird flocks has long i... Read More about Upwash exploitation and downwash avoidance by flap phasing in ibis formation flight.

Vaulting mechanics successfully predict decrease in walk-run transition speed with incline (2013)
Journal Article
Hubel, T. Y., & Usherwood, J. R. (2013). Vaulting mechanics successfully predict decrease in walk-run transition speed with incline. Biology Letters, 9(2), https://doi.org/10.1098/rsbl.2012.1121

There is an ongoing debate about the reasons underlying gait transition in terrestrial locomotion. In bipedal locomotion, the ‘compass gait’, a reductionist model of inverted pendulum walking, predicts the boundaries of speed and step length within w... Read More about Vaulting mechanics successfully predict decrease in walk-run transition speed with incline.