Physical activity over 2,000 years in Milan: Using entheseal robusticity as indicator of occupational stress

Entheseal changes have been traditionally considered as indicators of skeletal markers of activity and occupational stress in bioarchaeology, although many factors may influence their development including age, sex, body size, pathological conditions, and traumatic injuries. In the present study, we scored and examined entheseal robusticity of 46 entheseal sites (23 left and right) of 250 skeletons from the Anthropological Collection of the Laboratory of Forensic Anthropology and Odontology in Milan, Italy. The skeletons come from the same urban and socioeconomic context (low/middle classes in Milan) and were equally divided between males and females and archaeologically dated to five consecutive time periods spanning from Roman to contemporary era, traversing a total of about 2,000 years. Analysis of entheseal robusticity focused on three aspects: asymmetry, differences between sexes and diachronic trends. While results revealed no statistically significant disparities between left and right side, differences were found in sexes potentially related to gender division of labor. In addition, post-hoc comparisons demonstrated significant changes in mean individual scores across historical periods, with an overall increase in robusticity for both sexes. These changes are consistent with historically documented activities performed by males and females over time in Milan. Through the analysis of the degree of robusticity of entheseal sites and by engaging with historical sources, the study explores physical activity in a major European metropolis and reveals its evolution in females and males over time.