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Thesis Format



Master of Arts




Stock, Jay T.


There is considerable evidence that differences in patterns of habitual activity influence the distribution of skeletal tissue within the human skeleton, but little is known about variation in soft tissue. This thesis examines body composition and surface scan data from runners, swimmers, and a ‘recreational control’ population to investigate differences in the properties of limb segment surface areas and volumes, muscle mass, and fat mass. It also explores the relationship between activity and aging through the examination of body composition and volumetric measurements in older-adult habitual swimmers. The findings show that resulting limb segment properties support assumptions of running as a lower-limb dominant and swimming as an upper limb dominant activity. Habitual swimming also displays a positive effect on the preservation of skeletal muscle mass across the life course. This thesis suggests non-impact loading results in demonstrable differences in body morphology, emphasizing the importance of activity throughout the life course.

Summary for Lay Audience

The interpretation of past lifeways is a critical component of bioarchaeological and research. Gaining a better understanding of how humans once lived is approached through a diversity of lenses, including interpreting past activity patterns. In understanding these histories, it is necessary to understand human variation, as it plays a key role in what these patterns might look like in one group compared to another. Humans have long inhabited a variety of environments, each with a unique set of challenges and associated activities (Cameron & Pfeiffer, 2014; Sternberg, 2008). It has been shown that habitual physical activity is associated with changes in bone density and shape, as well as changes in muscle and body fat distribution (Brown & Jones, 1977; Daly et al., 2008). Long-term activity patterns are likely to have shaped variation between groups in the past (Pearson, 2000).

This thesis investigates patterns of limb volume and surface area, as well as fat mass and muscle mass by comparing long-term runners and swimmers to a recreational control group. Similarly, it explores the relationship between activity and aging through the examination of muscle mass, limb segment volumes, and limb segment surface areas in older-adult habitual swimmers. Swimmers typically had a larger amount of their limb volume and surface area concentrated in their arms, relative to their legs, and runners typically had more of their limb volume and surface area concentrated in their legs, relative to their arms. The same patterns held true for muscle mass in both swimmers and runners. These results agree with the assumption that swimming results in more upper body muscle deposition and that running results in more lower-limb muscle recruitment and deposition. Furthermore, there was no correlation between age and skeletal muscle mass in regular swimmers. This suggests that like running, swimming also offers some protection against muscle loss in old age, even though swimming is a non-impact sport.

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License