Present Day Iguanodon
In 'The Origin of Birds' by Gerhard Heilmann 1927, there appears a drawing of a pair of sprinting Iguanodons.
Back to walking on all fours
During 1992/1993 a study of vertebrae in Iguanodon skeletons lead experts to suggest that Iguanodon would not walk in an upright bipedal mode, once fully grown.
It now seems that, while young Iguanodon may have had an element of bipedality about them, fully grown adults would have been dominantly quadrupeds, occasionally rearing onto their hind legs for feeding.
The Natural History Museum have now corrected the stance of their Iguanodon to reflect this. The original concept of quadrupedality, evident in Mantells and Owens early drawings, is thus restored.
In 1997 the European Association for Research in Legged Robots (EARLR) published information about a 2 year research project in which a half scale robotic replica of Iguanodon atherfieldensis was manufactured - a Palaiomation project.
The fossilized skeleton was studied in detail using a laser scanner, and 3 generations of prototypes were constructed. The final electrically-actuated robot had full automotive locomotion using multiple sensors and control systems.