RE: T. rex biomechanics

[John Hutchinson <jrhutch@rvc.ac.uk>]

Hi,

Short answer, yes, same muscle groups (hip extensors/femoral retractors).
Although in bending down those muscles would mainly act as brakes; gravity
could do much of the work passively as theropods were front-heavy (center of
mass forward of hips).

Cheers,
John

> -----Original Message-----
> From: ptnorton [mailto:ptnorton@suscom-maine.net] 
> Sent: 29 September 2007 23:39
> To: Dinosaur list mail
> Subject: T. rex biomechanics
> 
> 
> I've read all the papers by Hutchinson and Alexander relating 
> to the hip and 
> leg biomechanics of T. rex, but still have what is probably a 
> relatively 
> basic question. This is no fault of their fine work by any 
> means; they just 
> didn't address this specific point.
> 
> If a T. rex was standing still and had to rotate its upper 
> body downward in 
> order to pick something off the ground (either with it arms 
> or its mouth), 
> would the muscles that were subsequently called upon to 
> elevate the delicate 
> little guy's upper body back towards horizontal equilibrium 
> be the same 
> muscles that generated dynamical running forces by flexing 
> (i.e., pulling 
> backwards) the femur? In the free body biomechanical diagrams 
> I've been 
> playing with recently it appears that, given the overall 
> architecture of T. 
> rex, both actions would essentially rely on the same muscle groups.
> 
> Anyone have any thoughts on this?
> 
> PTJN 
> 
> 
>