This thesis explores four physical behaviours thought to be important in the evolution of hominids, namely climbing, squatting, running and throwing. It aims to comprehensively explore the evolutionary background and anatomical adaptations involved in each behaviour, and to holistically explore the concept of evolutionary mismatch in modern humans. My approach employed a series of systematic reviews, with each behaviour being considered independently. Search terms specific to each behaviour were used in three different literature search engines to identify relevant articles by title and abstract, before a full read through applying additional criteria determined their eligibility. Articles meeting all the relevant criteria, such as containing specific reference to the behaviour in question within an evolutionary context, made up the literature base for each review.
Climbing is hominids’ most ancient locomotory mode, with evidence for its utilisation stretching back at least 20 million years ago (mya) to some of the earliest hominid fossils currently known. Its use greatly diminished with the adoption of habitual bipedalism, particularly within the genus Homo, although it retained usefulness for certain foraging behaviours such as the acquisition of honey. Anatomical adaptation for climbing is mostly seen in the shoulder and hands as the major weight-bearers. Prolonged deep squatting is a posture that equals climbing in terms of time-depth, and was used by our ancestors as a means of simple resting or for key behaviours such as defaecation and childbirth. Its significance has received little attention. Evidence for squatting is found in the ankle with ‘squatting facets’ present upon the talus in archaeological samples. Ankle dorsiflexion seems to be the key limiting factor of this posture. Endurance running is a behaviour adopted by hominins as they became terrestrial hunter-gatherers, likely as a means of moving swiftly to pursue hunts or scavenging opportunities. Major adaptations for running are found throughout the modern human body, including spring-like tendons in the legs, large articular surfaces on weight-bearing joints, stabilising upper-body mechanics and several specialist thermoregulatory features. Finally, projectile throwing in combination with more sophisticated hafting of weaponry vastly improved the hunting success of later hominins- certainly Homo sapiens but also, most likely, Homo neanderthalensis. Adaptation for throwing in modern humans can be seen notably in the shoulder, wrist and hands.
Modern humans in today’s society behave very differently. Behaviours such as climbing and running, which were once so important to our hominin ancestors, now have little bearing on our survival. This is partly due to technological innovation and our emerging division of labour. One health concern of such a shift is the risk of evolutionary mismatch, with barefoot running being the most well-known case: several authors have suggested that a lack of running is a source of health concern for our running-adapted species. The information reviewed herein suggests further possible mismatches, such as the lack of squatting and abundance of chairs in modern society, a lack of general daily strenuous activity, and perhaps interaction between behaviours that require similar anatomical adaptations. Although further work is needed on the specific topics covered, this thesis concludes that the modern human form is adapted to regularly perform a range of physical activities, and that cross-training might be a key way of improving health and fitness today.