Height plays a role
When we attempt to minimize our visibility and noise, we often move with a particular gait, bending our knees and leaning forward. This method of movement, known as crouched walking, has been historically employed, for example, when escaping dangerous situations or approaching prey. The efficiency of movement played a significant role in the acquisition of bipedalism (the use of two legs for walking) by our human ancestors. Specifically, a person's stature, notably their height, plays a substantial role in determining the energy demands of motion. The details of the mechanisms of crouched walking were studied by scientists Martin Hora, Michal Struška, and Vladimír Sládek from the Bone Tissue Anthropology Lab at the Faculty of Science, Charles University.
The study of muscle activity during crouched walking opens a fascinating window into the past and potential contemporary applications. Over the past few decades, this issue has been explored from the perspective of hominid bipedal evolution and movement disorders in modern humans. However, a lesser-known aspect is the utilization of crouched walking in hunting practices, where body posture played a pivotal role. Hunters typically employed crouched walking to approach their prey. This type of gait allowed for flexible adjustments in postural height (the actual height of the body from the ground to the top of the head) depending on vegetation and terrain. Thus minimizing the risk of being seen and heard, enabling hunters to get close to the animal without triggering its flight response.
Source: flickr.com, by Charles Fred
Crouched walking may appear highly advantageous, but that's not entirely true. This method of movement requires higher muscle activity of the quadriceps muscle (knee extensors), resulting in an increased energy demand of 27% to 229% compared to normal walking. This higher energy expenditure negatively impacts endurance, meaning that, compared to upright walking where muscles are less taxed, individuals become fatigued more quickly and require rest sooner.
Previous studies on muscle activity have been limited to just two different crouched positions, which had little variation between them. Therefore, it's not known how body position and muscle activity differs during crouched walking at different postural heights and at higher levels of crouching. This study, therefore, focuses on analyzing the relationship between postural height, posture, and muscle activity in the lower limbs during crouched walking.
Nineteen adult men participated in the research. The participants walked barefoot on a seven-meter track and performed four different tasks: extended limb walking, lightly crouched walking, moderately crouched walking, and severely crouched walking. The collected data indicated that individuals with a lower posture (deep crouch) during crouched walking exhibited greater muscle activity in the lower limbs.
The results suggest that shorter hunters, who do not have to crouch as much when using a cover of a certain height, might have better persistence compared to taller hunters. This would mean that the shorter stature of our earlier Neanderthal relatives and the contemporary San of the Kalahari may be an advantage when hunting at close range. This implies that the shorter stature of our earlier Neanderthal relatives and the contemporary San of the Kalahari and the Philippine Aetas could be advantageous in close-range hunting. The results of this study can contribute to our deeper understanding of human bipedal evolution and the potential advantages of shorter stature in close-range hunting. This study offers a fresh perspective on the past and can help us better comprehend the movement and lives of our ancestors.
Yulia Dyachenko
Published:
Dec 04, 2023 09:15 PM
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