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Background/Objectives: This study explores an optimization-based strategy for muscle force estimation by employing simplified cost functions integrated with physiologically relevant muscle models. Methods: Considering elbow flexion as a case study, we employ an inverse-dynamics approach to estimate muscle forces for the biceps brachii, brachialis, and brachioradialis, utilizing different combinations of cost functions and muscle constitutive models. Muscle force generation is modeled by accounting for active and passive contractile behavior to varying degrees using Hill-type models. In total, three separate cost functions (minimization of total muscle force, mechanical work, and muscle stress) are evaluated with each muscle force model to represent potential neuromuscular control strategies without relying on electromyography (EMG) data, thereby characterizing the interplay between muscle models and cost functions. Results: Among the evaluated models, the Hill-type muscle model that incorporates both active and passive properties, combined with the stress minimization cost function, provided the most accurate predictions of muscle activation and force production for all three arm flexor muscles. Our results, validated against existing biomechanical data, demonstrate that even simplified cost functions, when paired with detailed muscle models, can achieve high accuracy in predicting muscle forces. Conclusions: This approach offers a versatile, EMG-free alternative for estimating muscle recruitment and force production, providing a more accessible and adaptable tool for muscle force analysis. It has profound implications for enhancing rehabilitation protocols and athletic training, not only broadening the applicability of muscle force estimation in clinical and sports settings but also paving the way for future innovations in biomechanical research. 

Abstract Zero‐dimensional (0D) organic metal halide hybrids (OMHHs) are emerging materials with significant potential for optoelectronic applications, including direct X‐ray detectors. While 0D OMHH single crystals exhibit excellent X‐ray detection properties, their scalability remains a significant challenge due to the time‐intensive growth process and difficulty in producing large single crystals exceeding a few centimeters. This limitation hinders their practicality for large‐area detector applications. Here, we report for the first time the development of amorphous 0D OMHH films via solution processing for efficient direct X‐ray detection. By reacting a non‐crystalline organic halide, triphenyl(9‐phenyl‐9H‐carbazol‐3‐yl)phosphonium bromide (TPPCarzBr), with zinc bromide (ZnBr₂), we have successfully produced amorphous 0D (TPPCarz)₂ZnBr₄films with controlled thickness via facile solution processing. The organic cations (TPPCarz⁺) feature a lower bandgap than the ZnBr₄²⁻anions, enabling efficient molecular sensitization, where ZnBr₄²⁻anions serve as X‐ray absorbers and TPPCarz⁺ cations as charge transporters. Direct X‐ray detectors based on 0D (TPPCarz)₂ZnBr₄films demonstrate outstanding performance, achieving a stable X‐ray detection sensitivity of 2,165 µC Gy_air⁻¹cm⁻²at 20 V mm⁻¹ and a detection limit of 6.01 nGy_air s⁻¹. The amorphous nature of these films enhances their processability, allowing for fabrication in various sizes and shapes, and making them highly adaptable for scalable detector applications.