Effects of rifle handling length and supporting length on aiming performance and biomechanics

<i>Purpose</i>: One of the most crucial factors affecting shooting performance is aiming stability, which is affected by the human-gun parameters. The effect of human-gun parameters on performance and biomechanics has not been investigated due to experimental limitations. This paper analyzed the aiming stability and biomechanics under different rifle handling length and supporting length based on experiments and musculoskeletal model. <i>Methods</i>: The aiming performance and balance posture with various rifle handling length and supporting length was obtained by the motion capture system. The artificial neural network was established to map the handling length and supporting length to the body balance posture. The human-gun musculoskeletal model calculated the joint reaction forces and muscle activation with different balance postures. <i>Results</i>: The effect of handling length and supporting length on aiming stability and biomechanics was analyzed. The muscle activation pattern was identified, and it could explain 83.8-98.2% of the variance in aiming stability. <i>Conclusions</i>: The outcomes of this study could find the most suitable human-gun parameters for shooters to improve performance and reduce the risk of musculoskeletal injury.