## 1 Introduction
Specifically, regarding lower limb functional recovery, AR training has been shown to improve balance and gait in stroke patients [11, 12, 13], and even home-based AR exercises have positively impacted balance ability after stroke [14]. Similarly, in studies involving older adults, AR-based Otago exercises demonstrated improvements in balance, gait ability, and fall self-efficacy [15]. Training utilizing 3D AR systems has been shown to enhance stability, reduce the risk of falls, and improve balance [16], while AR-based physical exercises effectively increased walking speed and balance ability [17]. Research on the therapeutic applications of AR for amputee patients includes case studies demonstrating its effectiveness in reducing phantom limb pain in upper limb amputees [18]. However, studies concerning lower limb amputees have primarily focused on the interventional effects of Virtual Reality (VR) training, which offers a higher level of immersion compared to AR. These VR studies have reported significant improvements in balance metrics (e.g., Berg Balance Scale, Timed Up and Go test, Dynamic Gait Index) when compared to traditional training methods [19]. Specifically, a case study on transtibial amputees indicated that VR-based gait training providing real-time feedback effectively improved hip, pelvis, and trunk movements,reduced oxygen consumption, and enhanced overall gait performance [20]. Furthermore, rehabilitation interventions combining VR training with traditional methods have been shown to positively impact pain reduction, depression, and mental health status in lower limb amputees [21]. Immersive VR game training has also been found to contribute to improved proprioception, balance, and agility in transfemoral amputees [22]. Nevertheless, there is a current lack of research directly investigating the impact of AR systems on lower limb amputees, particularly concerning movement accuracy and subjective satisfaction. Based on the positive results of AR-based rehabilitation training observed in studies involving stroke patients and older adults, particularly AR's potential for lower limb functional recovery and balance improvement, we hypothesize that applying AR-based visual feedback to rehabilitation training for lower limb amputees will enhance movement accuracy and consequently improve exercise efficacy compared to training without such feedback. Therefore, this study aims to differentiate itself from existing VR research by comparing and analyzing differences in movement accuracy and subjective satisfaction based on the application of an AR system in unilateral lower limb amputees. The goal of this study is to empirically verify the immediate effects of using AR systems in lower limb amputee rehabilitation, and to provide essential foundational data for the future development and clinical application of customized AR-based rehabilitation training programs. This paper begins with an introduction that outlines the potential of AR technology in rehabilitation and the current limitations in lower limb amputee rehabilitation, thereby establishing the necessity and objective of the study. The research methodology section then elaborates on the study participants, system, equipment, and procedures. Following this, the results section presents the analysis of movement accuracy and subjective satisfaction based on the application of the AR system. These findings are thoroughly interpreted in the discussion, and finally, the conclusion summarizes the key discoveries and future prospects.