Careful research by Liverpool scientists appears to confirm that Australopitecus afarensis (or whichever australopithecine species that left the footprints at Laetoli, Tanzania) walked like us or almost so, rather than in the crouched position that has been long attributed to them.
Discussed at Science Daily.
Ref. Robin H. Crompton et al. Human-like external function of the foot, and fully upright gait, confirmed in the 3.66 million year old Laetoli hominin footprints by topographic statistics, experimental footprint-formation and computer simulation. Journal of the Royal Society, 2011. Pay per view.