“…The biomechanics of the type of free-hand knapping used for making the core tools and flakes that typify the Oldowan has received more attention (e.g., Bril et al, 2010;Hamrick et al, 1998;Key & Dunmore, 2015;Marzke & Shackley, 1986;Marzke et al, 1998;Mateos et al, 2019;Williams et al, 2010), but research focused on the hand is comparatively limited, making it difficult to evaluate functional and adaptive hypotheses. What we do know regarding hand function during free-hand knapping is that a wide variety of grips are used, with a significant emphasis on precision grips (Key et al, 2018;Williams-Hatala et al, 2021). Loads tend to be concentrated on the pollex in both the dominant (Rolian et al, 2011;Williams-Hatala et al, 2018;Williams-Hatala et al, 2021, contra Williams et al, 2012 and non-dominant hands (Key & Dunmore, 2015), followed by the second ray, whereas the ulnar rays on both hands experience significantly lower loads (Key et al, 2019;Williams-Hatala et al, 2018.…”