Experimental grinding has been used to study the relationship between human humeral robusticity and cereal grinding in the early Holocene. However, such replication studies raise two questions regarding the robusticity of the results: whether female nonathletes used in previous research are sufficiently comparable to early agricultural females, and whether previous analysis of muscle activation of only four upper limb muscles is sufficient to capture the stress of cereal grinding on upper limb bones. We test the influence of both of these factors. Electromyographic activity of eight upper limb muscles was recorded during cereal grinding in an athletic sample of 10 female rowers and a nonathletic sample of 25 females and analyzed using both an eight- and four-muscle model. Athletes had lower activation than nonathletes in the majority of measured muscles, but most of these differences were non-significant. Furthermore, both athletes and nonathletes had lower muscle activation during saddle quern grinding than rotary quern grinding suggesting that the nonathletic sample can be used to model early agricultural females during saddle and rotary quern grinding. Similarly, in both eight- and four-muscle models, upper limb loading was lower during saddle quern grinding than during rotary quern grinding, suggesting that the upper limb muscles may be reduced to the previously used four-muscle model for evaluation of the upper limb loading during cereal grinding. Another implication of our measurements is to question the assumption that skeletal indicators of high involvement of the biceps brachii muscle can be interpreted as specifically indicative of saddle quern grinding.

中文翻译：

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上肢训练和分析肌肉对使用鞍形旋转磨和旋转旋转磨的谷物研磨过程中体力活动估计的影响

实验研磨已用于研究全新世早期人类肱骨稳健性与谷物研磨之间的关系。但是，这样的复制研究对结果的稳健性提出了两个问题：以前的研究中使用的女性非运动员是否足以与早期的农业女性进行比较，并且先前对仅四条上肢肌肉的肌肉激活进行的分析是否足以捕获女性的压力。谷物在上肢骨骼上研磨。我们测试了这两个因素的影响。在10名女性划船者的运动样本和25名女性的非运动样本中进行谷物碾磨时，记录了八只上肢肌肉的肌电活动，并使用八肌肉模型和四肌肉模型进行了分析。在大多数测得的肌肉中，运动员的活动性低于非运动员，但这些差异中的大多数并不显着。此外，运动员和非运动员在鞍形磨削过程中的肌肉活化程度均低于旋转式磨削，这表明非运动员样本可用于在鞍形和旋转式磨削过程中为早期的农业女性建模。同样，在八肌肉模型和四肌肉模型中，鞍形磨削过程中上肢的负荷都比旋转磨削过程中的下肢负荷低，这表明上肢肌肉可能会减少到先前用于评估上肢的四肌肉模型中谷物研磨过程中装载。