Research Topics
| James Richard UsherwoodSummaryAffiliation: Royal Veterinary College Country: UK Publications
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Detail Information
Publications
The human foot and heel-sole-toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?J R Usherwood
Structure and Motion Laboratory, The Royal Veterinary College, North Mymms, Hatfield, Herts AL9 7TA, UK
J R Soc Interface 9:2396-402. 2012....- Energetically optimal running requires torques about the centre of massJames R Usherwood
Structure and Motion Laboratory, The Royal Veterinary College, University of London, North Mymms, Hatfield, Herts AL9 7TA, UK
J R Soc Interface 9:2011-5. 2012.... 
Inertia may limit efficiency of slow flapping flight, but mayflies show a strategy for reducing the power requirements of loiterJames R Usherwood
Structure and Motion Lab, The Royal Veterinary College, North Mymms, Hatfield, Herts, UK
Bioinspir Biomim 4:015003. 2009..However, flapping may confer advantages in terms of top speed and manoeuvrability. If flapping-winged micro air vehicles are required to hover or loiter more efficiently, dragonflies and mayflies suggest biomimetic solutions...- Compass gait mechanics account for top walking speeds in ducks and humansJames R Usherwood
Structure and Motion Laboratory, The Royal Veterinary College, North Mymms, Hatfield, Hertfordshire AL9 7TA, UK
J Exp Biol 211:3744-9. 2008..Therefore, the capacity to drive the swing leg forward by walking humans may be a specialization for walking, allowing near-passive vaulting of the CoM at walking speeds 4/3 that possible with a passive (duck-like) swing leg... - Inverted pendular running: a novel gait predicted by computer optimization is found between walk and run in birdsJames Richard Usherwood
The Royal Veterinary College, North Mymms, Hatfield, Herts, UK
Biol Lett 6:765-8. 2010..Both pheasants and guineafowl demonstrate each gait at close to the predicted speed/step length combinations, although fully aerial ballistic phases are never achieved during the hybrid or 'Grounded Inverted Pendular Running' gait... 
Mechanics of dog walking compared with a passive, stiff-limbed, 4-bar linkage model, and their collisional implicationsJames R Usherwood
The Royal Veterinary College, North Mymms, Hatfield, Herts, UK
J Exp Biol 210:533-40. 2007..Footfall timings and timing of mechanical energy fluctuations are consistent with strategies to reduce collisional forces, analogous to the suggested role of ankle extension as an efficient powering mechanism in human walking...- Accounting for elite indoor 200 m sprint resultsJames R Usherwood
Structure and Motion Laboratory, The Royal Veterinary College Hawkshead Lane, North Mymms AL9 7TA, UK
Biol Lett 2:47-50. 2006..Even elite athletes appear constrained by limb forces... - Why not walk faster?James Richard Usherwood
Structure and Motion Laboratory, The Royal Veterinary College, University of London, North Mymms, Herts AL9 7TA, UK
Biol Lett 1:338-41. 2005..At walking speeds approaching a Froude number of 1, take-off is only avoidable with very small steps. With realistic limitations on swing-leg frequency, a novel explanation for the walk-run transition at a Froude number of 0.5 is shown... - Flying in a flock comes at a cost in pigeonsJames R Usherwood
Structure and Motion Laboratory, The Royal Veterinary College, University of London, North Mymms, Hatfield AL9 7TA, UK
Nature 474:494-7. 2011..Indeed, the increased flap frequency, whether due to direct aerodynamic interactions or requirements for increased stability or control, suggests a considerable energetic cost to flight in a tight cluster flock... - Biomechanics: no force limit on greyhound sprint speedJames R Usherwood
Structure and Motion Laboratory, The Royal Veterinary College, North Mymms, Hertfordshire AL9 7TA, UK
Nature 438:753-4. 2005..This supports the idea that greyhounds power locomotion by torque about the hips, so--just as in cycling humans--the muscles that provide the power are mechanically divorced from the structures that support weight... - Dynamic pressure maps for wings and tails of pigeons in slow, flapping flight, and their energetic implicationsJames R Usherwood
Concord Field Station, Harvard University, 100 Old Causeway Road, Bedford, MA 01730, USA
J Exp Biol 208:355-69. 2005..5% of the force required to support weight was provided by the wings, and that the aerodynamic muscle-mass specific power required to flap the wings was 272.7 W kg(-1)... - Two explanations for the compliant running paradox: reduced work of bouncing viscera and increased stability in uneven terrainMonica A Daley
Structure and Motion Laboratory, Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire AL9 7TA, UK
Biol Lett 6:418-21. 2010..Our models suggest compromises in leg control for economy and stability that might explain why animals run with compliant legs... - The aerodynamics of avian take-off from direct pressure measurements in Canada geese (Branta canadensis)James R Usherwood
Concord Field Station, Harvard University, 100 Old Causeway Road, Bedford, MA 01730, USA
J Exp Biol 206:4051-6. 2003.... - Running over rough terrain: guinea fowl maintain dynamic stability despite a large unexpected change in substrate heightMonica A Daley
Concord Field Station, MCZ, Harvard University, Old Causeway Road, Bedford, MA 01730, USA
J Exp Biol 209:171-87. 2006.... - Wing inertia and whole-body acceleration: an analysis of instantaneous aerodynamic force production in cockatiels (Nymphicus hollandicus) flying across a range of speedsTyson L Hedrick
Concord Field Station, Museum of Comparative Zoology, Harvard University, 100 Old Causeway Road, Bedford, MA 01730, USA
J Exp Biol 207:1689-702. 2004.... - Pitch then power: limitations to acceleration in quadrupedsSarah B Williams
Structure and Motion Laboratory, The Royal Veterinary College, University of London, Hatfield, Herts AL9 7TA, UK
Biol Lett 5:610-3. 2009..At low speed, acceleration and deceleration may be limited by the geometric constraints of avoiding net nose-up or tail-up pitching, respectively. At higher speeds, muscle power appears to limit acceleration... - Phasing of dragonfly wings can improve aerodynamic efficiency by removing swirlJames R Usherwood
Structure and Motion Lab, The Royal Veterinary College, North Mymms, Hatfield, Herts, UK
J R Soc Interface 5:1303-7. 2008....