| Kim P. Deckers |
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Figure 1. Femoral Lengths Across Fossil Hominins (Data
taken from Jungers et al. 2009, 543; Lordkipanidze et al.
2007, 307; Trinkhaus and Ruff 2012, 35)
Discussion
Proponents of the endurance running hypothesis
argue that the anatomical traits described by
Bramble and Lieberman (2004, 348) are more
elongated Achilles tendon necessary for endurance
running. An increase in robusticity of the calcaneal
tuber is observed in modern humans. This feature,
combined with a shortened tuber, may be indicative
of endurance running. Although too damaged to
assess tuber length, a calcaneus from Homo naledi
exhibits a gracile calcaneal tuber whose robusticity
falls outside the range of modern human variation
(Harcour-Smith et al. 2015, 2). This would indicate
that this species may have been capable of running,
but most likely did not engage in endurance running
behaviours similar to that of modern humans.
However, it has not been possible at this time to date
these fossil remains to an accurate age range, which
makes it impossible to assess where these creatures
fall within the hominin sequence (Berger et al. 2015,
24; Dembo et al. 2016, 24; Stringer 2015, e10627;
Thakerey 2015, 1).
Not only do most features described (tab. 3)
appear before the appearance of Homo erectus,it is
questionable whether these features are indicative
of running at all. The increase in lower limb length
(with the exception of
) would
be indicative of endurance running capabilities
according to Bramble and Lieberman (2004, 348)
and does occur in Homo habilis and Homo erectus.
However, analysis of differences in cost of transport
in walking and running in modern humans indicated
that some of these features are already present in
hominins that are just starting to become bipedal
(tab. 3). This would suggest that these features may types of locomotion (Steudel-Numbers et al. 2007,
195) and that endurance walking during persistence
in mind that an early presence of these features does
not exclude the possibility that their morphology it cannot be denied that Homo erectus shows a
l o c o m o t i o n o r r u n n i n g o v e r e v o l u t i o n a r y t i m e .
When a feature is solely related to running, as is the
case with the calcaneal tuber, this still cannot provide
conclusive evidence that endurance running evolved
at around 1.8 million years ago with Homo erectus.
Calcaneal tuber length is related to Achilles tendon be noted that this trend of increased limb length can
be observed in earlier Homo species as well. It could
be argued that this increase in limb length may be an
artefact of increased bipedal walking, not running.
Australopithecus afarensis
(Ward et al. 2012, 39) further indicate that features
such as the longitudinal arch were present much
sooner in evolutionary history and are more likely
related to increased bipedal walking capabilities,
not running ability. The fact that shorter toes can
already be observed in Homo habilis (Kidd et al.
1996, 285) further corroborates this notion.
(Raichlen et al. 2011, 303). The comparison of
calcaneal tuber length between modern humans
and Neanderthals has shown that the latter does not
exhibit a shortened tuber, which is correlated with
this feature (Raichlen et al. 2011, 304). Whether
this represents an evolutionary reversal, or that
shorter calcaneal tubers did not evolve until Homo
sapiens cannot be answered until a Homo erectus
calcaneus is found. Until such as fossil is found, it
is only safe to say that modern humans exhibit the
p. 10 | VOL III | INTER-SECTION | 2017
running (Steudel-Numbers et al. 2007, 195; Steudel-
A limitation of this study to testing the endurance
running hypothesis is that it focused on the lower
limb. Only one lower limb feature solely related
tuber length. The results of this study do indicate