Ergonomic relationships that minimize muscle activity relative to the creation of cutting stress underpin the design of modern knives, saws, and axes. The Palaeolithic archaeological record, and the > 3 million years of technological behavior that it represents, is predominantly characterized by sharp stone implements used for cutting. To date, we do not know whether Palaeolithic hominins adhered to ergonomic principles when designing stone tools, if lithic technological transitions were linked to ease-of-use advances, or even how muscularly demanding different Palaeolithic tools are on an empirically defined relative basis. Here, we report the results of an experimental program that examines how four key stone tool types, produced between ∼ 3.3 million and ∼ 40 thousand years ago, influence muscle activation in the hominin upper limb. Using standardized laboratory-based tests designed to imitate Pleistocene cutting behaviors, surface electromyography recorded electrical activity (amplitude) in nine muscles across the hand, forearm and shoulder of modern humans during the use of replica Lomekwian, Oldowan, Acheulean and Mousterian stone tools. Results confirm digit flexors and abductors, particularly the first dorsal interosseous and flexor pollicis longus, to be the most heavily recruited muscles during the use of all tool types. Significant differences in muscle activation are, however, identified dependent on the type of stone tool used. Notably, the abductor digiti minimi, flexor pollicis longus, and biceps brachii were highly activated during handaxe use, particularly when compared to the use of Oldowan and Levallois flakes. Results are discussed in light of current understanding on the origin of Lower and Middle Palaeolithic technologies, why specific tool types were produced over others during these periods, and the extent to which early hominins produced ergonomically designed tools.

中文翻译：

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在 300 万年的旧石器时代技术转型中，肌肉募集和石器使用人体工程学。

与产生切割应力相关的最大程度减少肌肉活动的人体工程学关系是现代刀具、锯和斧头设计的基础。旧石器时代的考古记录，以及它所代表的 > 300 万年的技术行为，主要特征是用于切割的锋利石器。迄今为止，我们不知道旧石器时代的古人类在设计石器时是否遵循了人体工程学原理，石器技术的转变是否与易用性的进步有关，甚至不知道在经验定义的相对基础上对不同旧石器时代工具的肌肉要求有多高。在这里，我们报告了一个实验程序的结果，该程序检查了大约 330 万到大约 4 万年前生产的四种关键石器类型如何影响人类上肢的肌肉激活。使用旨在模仿更新世切割行为的标准化实验室测试，表面肌电图记录了现代人在使用复制品 Lomekwian、Oldowan、Acheulean 和 Mousterian 石器期间，手、前臂和肩部的九块肌肉的电活动（振幅）。结果证实手指屈肌和外展肌，特别是第一背侧骨间肌和拇长屈肌，是在使用所有工具类型期间募集最多的肌肉。然而，肌肉激活的显着差异取决于所使用的石器类型。值得注意的是，在使用手斧时，小指外展肌、拇长屈肌和肱二头肌高度激活，尤其是与使用 Oldowan 和 Levallois 薄片相比时。