Cross Samuel R R, Charles James P, Sellers William I, Codd Jonathan R, Bates Karl T
Institute of Life course and Medical Sciences, University of Liverpool, Liverpool, UK.
School of Earth and Environmental Sciences, University of Manchester, Manchester, UK.
R Soc Open Sci. 2025 May 21;12(5):242109. doi: 10.1098/rsos.242109. eCollection 2025 May.
The body fossil record cannot preserve the dynamics of animal locomotion, and the only way to systematically reconstruct it is through simulation. However, musculoskeletal models used in simulation studies are typically simplified, meaning that their efficacy must first be demonstrated on living animals. Here, we evaluate a workflow for forward-dynamics simulations of maximum-effort vertical jumping, using simplified human and guineafowl models built with muscle masses from either measured data or estimated with methods previously applied to fossils. Predicted human performance was approximately 10% below experimental averages when known muscle masses were used, while the error ranged between +3 and -10% with palaeobiological methods. The simulations also correctly replicated the kinematic strategies (countermovement or squat jump) used across different starting postures. In contrast, predicted guineafowl performance was around 50-60% experimental values, irrespective of reconstruction method. Guineafowl model underperformance likely reflects simplifications related to foot mobility, muscle activation speeds and muscle fibre lengths, with the latter potentially being adaptively important to exceptional avian jumping performance. These findings emphasize that current muscle reconstruction and simulation approaches are most suited for evolutionary analyses where broad changes in body morphology and posture may significantly impact vertical jumping through pronounced qualitative differences in kinematic strategy.
身体化石记录无法保存动物运动的动态过程，而系统重建它的唯一方法是通过模拟。然而，模拟研究中使用的肌肉骨骼模型通常是简化的，这意味着它们的有效性必须首先在活体动物上得到证明。在这里，我们评估了一种用于最大努力垂直跳跃的正向动力学模拟的工作流程，使用了简化的人类和珠鸡模型，这些模型的肌肉质量是根据测量数据构建的，或者是用先前应用于化石的方法估计的。当使用已知的肌肉质量时，预测的人类表现比实验平均值低约10%，而使用古生物学方法时误差在+3%到-10%之间。模拟还正确地复制了不同起始姿势所采用的运动学策略（反向运动或深蹲跳）。相比之下，无论采用何种重建方法，预测的珠鸡表现约为实验值的50%-60%。珠鸡模型表现不佳可能反映了与足部灵活性、肌肉激活速度和肌肉纤维长度相关的简化，其中后者可能对鸟类出色的跳跃表现具有适应性重要意义。这些发现强调，当前的肌肉重建和模拟方法最适合用于进化分析，在进化分析中，身体形态和姿势的广泛变化可能通过运动学策略上明显的质的差异对垂直跳跃产生重大影响。
