Raw data for: Biomechanical demands of percussive techniques in the context of early stone toolmaking

Recent discoveries in archaeology and palaeoanthropology highlight that
stone stool knapping could have emerged first within the genera
Australopithecus or Kenyanthropus rather than Homo. To explore the
implications of this hypothesis  determining the physical demands
and motor control needed for performing the percussive movements during
the oldest stone toolmaking technology (i.e. Lomekwian) would help. We
analysed the joint-angle patterns and muscle activity of a knapping expert
using three stone tool replication techniques: unipolar flaking on passive
hammer (PH), bipolar flaking on anvil (BP), multidirectional and
multifacial flaking with free hand (FH). PH presents high levels of
activity for Biceps brachii and the wrist extensors and flexors. By
contrast, BP and FH are characterised by high solicitation of forearm
pronation. The synergy analyses depict a high muscular and kinematic
coordination. Whereas the muscle pattern is very close between the
techniques, kinematic pattern is more variable, especially for PH. FH
displays better muscle coordination and conversely lesser joint-angle
coordination. These observations suggest that the transition from anvil
and hammer to freehand knapping techniques in early hominins have been
made possible by the acquisition of a behavioural repertoire producing an
evolutionary advantage that gradually would have been beneficial for stone
tool production.