Search

During the Holocene, what is now the state of South Australia experienced a shift to a drier climate with more frequent droughts c. 4 ka. The 'intensification model' in Australian archaeology proposes that Aboriginal people adopted subsistence strategies that exploited resources with high processing costs, while the 'risk minimization' model posits that people adopted more flexible foraging strategies. The purpose of this study is to determine whether human groups in South Australia demonstrate evidence for intensification or risk minimisation in response to declining patch quality by examining bone properties of the upper limb in a Holocene skeletal sample from Roonka. Cross-sectional geometry of the humeri and radii was used to examine temporal trends of diaphyseal rigidity and bilateral asymmetry in both sexes. Women show a significant temporal increase in robusticity and rigidity of the upper limbs; men have similar measurements between time periods. Neither sex exhibits a difference in bilateral asymmetry of the humeri and radii over time. These results support risk minimisation at Roonka. In the late Holocene, it is possible that men hunted large game, while women had mixed foraging strategies that involved hunting small game, digging tubers, processing seeds, and collecting shellfish to mitigate high resource variance. [ABSTRACT FROM AUTHOR]

Impact is an important aspect of the kicking skill. This study examined foot and ball motion during impact and compared distance and accuracy punt kicks. Two-dimensional high-speed video (4000 Hz) captured data of the shank, foot and ball through impact of 11 elite performers kicking for maximal distance and towards a target 20 m in distance. Four phases were identified during impact, with an overall reduction in foot velocity of 5.0 m · s−1(± 1.1 m · s−1) and increase in ball velocity of 22.7 m · s−1(± 2.3 m · s−1) from the start to end of contact. Higher foot velocity was found in distance compared to accuracy kicks (22.1 ± 1.6 m · s−1vs. 17.7 ± 0.9 m · s−1,P < 0.05), and was considered to produce the significant differences in all impact characteristics excluding foot-to-ball speed ratio. Ankle motion differed between the kicking tasks; distance kicks were characterised by greater rigidity compared to accuracy kicks evident by larger force (834 ± 107 N vs. 588 ± 64 N) and smaller change in ankle angle (2.2 ± 3.3° vs. 7.2 ± 6.4°). Greater rigidity was obtained by altering the position of the ankle at impact start; distance kicks were characterised by greater plantarflexion (130.1 ± 5.8° vs. 123.0 ± 7.9°,P < 0.05), indicating rigidity maybe actively controlled for specific tasks. [ABSTRACT FROM PUBLISHER]