Welcome back. We're pleased you're joining us for the fourth weekly module of this course, The Truth in Our Bones, How Human Skeletal Remains Tell Us About Past People. This module is about some of the ways we can detect physical activity from the skeleton and what types of activities we might be able to see. Marks left in both your bones and your teeth can leave clues about the activities you commonly engaged in. Two terms you'll hear us use often need to be defined. Those are robust and gracile. Robust refers to a structure or feature that is heavier and bulkier. In the case of marks in the skeleton, a considerable part of the cause of robusticity is large and heavily used muscles and gracile is the opposite. It refers to a light and slender structure feature associated with correspondingly smaller and less intensively used muscles. These days you may categorize the range of one's activities into something like occupations or your job versus what you do in your leisure time, or for fun. In much of the past, and indeed for many people living today, such a strict division didn't really exist, at least not in regards to something like a five day a week, nine to five job. And I bring this up to put the concept of activity into a useful framework whereby we keep in mind that, in a lot of cases, the idea of every person having a specific job or occupation doesn't necessarily fit that well with the way life worked in the past. And this is why it's more appropriate in many cases at least, to speak of solely physical activity rather than occupation in terms of what we can detect from your skeleton. We are able to see a long term average, the result of years of repetitive physical activity, not occasional or brief bouts. So people worked when it was necessary to obtain the food and materials needed to survive. Throughout the year and, indeed, throughout one's entire lifetime, that took varying amounts of time depending on numerous variables including access to resources, group cooperation, and the division of labour. The extent of class division and inequality in a society. And individual factors that bolstered or impeded one's ability and desire to work at certain tasks and many, many more variables. There's an online question in the discussion forum that asks you about this. What motivates you to work? This includes academic work like this MOOC, or maybe not work as the case may be. And whether this work is partially or primarily physical. Maybe you spend far too much time sitting at a desk like I do. And think about how this would have been different in the past, particularly before the commercialization of labour and market economies. The physical activities that you engage in over the course of your life mould and shape your bones and can lead distinctive marks on your bones and teeth. Osteoarchaeologists are very interested in using this phenomenon to reconstruct aspects of what people did in the past. For example, we can discern what muscles were the most heavily used and consider what activities would cause that pattern. We can investigate the similarities and differences between males and females in regards to markers of physical activity. And then, use that to investigate the gendered division of labour in a past society. This can vary quite a bit between populations. We can look at how these activity markers develop with age, to see at what age subadults began engaging in grown up tasks. It's often at a younger age than what we see today, as the Western concept of childhood is itself a rather recent invention. And we can track the rate of activity marker development to infer how intensively an activity was conducted. So that should give you a better idea of what we do and do not mean by physical activity. We're not referring to the couple of times last year that you went to the gym. That's not going to show up in your bones. We are referring to something, maybe you spent many years of your life digging holes in the ground. Say if you're an archaeologist, or a construction worker, or gardener, or maybe you've spent several decades chewing on pens when you study and work. There are a lot of possibilities as you might imagine. Stick with us to learn more. In this introduction to physical activity video, you've learned about what we mean by physical activity and osteoarchaeology. That it's not necessarily the same thing as occupation and that we see evidence of long-term, repetitive behaviours. We want you to think about how the physical activity you personally engage in or perhaps don't engage in, will be reflected in your bones. Coming up next is a video on the musculoskeletal system. In order to set you up to understand how your muscles and bones interact to create the marks on the skeleton we can use to infer activity patterns. See you there.
