The Near Eastern Middle Palaeolithic is associated with two hominid lineages, one of late archaic humans from Amud, Dederiyeh, Kebara, Shanidar and Tabun and the other of early modern humans from Qafzeh and Skhul. Biomechanical analysis of their humeral diaphyses, which are plastic in response to different loading regimes from activity patterns, reveals similar cross-sectional shapes, both in terms of cortical area relative to total area and in maximum to minimum bending rigidity. In this context, the late archaic humans have significantly more robust humeral diaphyses when cortical areas and especially polar moments of area are scaled to humeral lengths. These results join data from anterior dental attrition and upper limb morphology to indicate significantly greater use of the anatomy to accomplish manipulative tasks among these late archaic humans. However, given the associations of both groups with similar Middle Palaeolithic assemblages, it is the gracility of the Qafzeh-Skhul humans which is anomalous and requires explanation.