## 4 Discussion
Gait variability and reduced complexity are commonly associated with impaired mobility and increased fall risk [43]. DKA patients often exhibit altered gait patterns, including reduced stride length and walking speed, as part of a more cautious gait strategy [44]. In this study, EG participants demonstrated significant post-intervention improvements, including increased walking speed and reduced stride and step times during stair ambulation. These results suggest that the Aqua Vest-based unstable exercise program effectively enhanced stair gait performance while concurrently reducing knee pain, underscoring its potential for inclusion in rehabilitative and clinical interventions for DKA patients. Mediolateral (ML) sway is a critical factor in maintaining balance and is closely associated with fall risk. ML CoP parameters (distance and velocity) are frequently used as indicators of postural control deficits and fall susceptibility [12; 45]. After the intervention, EG participants exhibited significant reductions in ML CoP parameters, suggesting enhanced lateral postural control and stability. This improvement was likely due to the exercise regimen's emphasis on trunk control and activation of core and lower extremity muscles, facilitating the adoption of a more stable lateral balance strategy and reducing dynamic postural fluctuations. The effectiveness of resistance training using unstable surfaces and devices for rehabilitation has been widely established. Unstable loads increase time under tension, potentially leading to distinct training adaptations. In summary, unstable load training serves as an effective supplemental exercise by enhancing time under tension and maintaining high muscle activation across both primary and stabilizing muscles, even with lighter loads [35]. Performing exercises on unstable surfaces, such as the BOSU, increases co-contraction and antagonist muscle activity. While enhanced antagonist activity contributes to joint and muscle protection, it also improves motor control and balance [32]. According to [PERSON] and [PERSON] [46], unstable loads or bases can generate high-intensity internal muscle contractions despite reduced external force output, creating an effective training stimulus compared to stable conditions. Under unstable conditions, even a relatively small resistive torque at the distal limb can produce substantial motive torque through the torso. [PERSON] et al. [47] investigated muscle activity during squats using three instability tools (bar, BOSU, and water tube) and found that different instability sources altered electromyographic and kinematic patterns. These variations have implications for technique learning, rehabilitation, and training goal setting. Their findings suggest that selecting the appropriate instability tool should be guided by specific rehabilitation objectives. However, not all unstable devices are equally effective. [PERSON] and [PERSON] [48] found that certain unstable surfaces failed to significantly increase muscle activity during squats,particularly in highly resistance-trained individuals. Moderately unstable devices, such as the BOSU, did not enhance muscle activation in this population. Consequently, most research has focused on comparing the short-term effects of different instability tools. Among these, water-based instability devices have gained increasing attention for their applications in both performance enhancement and rehabilitation. Studies suggest that training with water-filled devices enhances muscle activation and challenges postural stability more effectively than stable load exercises [1; 33; 49; 50]. [PERSON] et al. [1] demonstrated that exercises with a water-filled tube (WT) resulted in greater core muscle activation and posed a more significant challenge to postural stability compared to traditional barbell training. Similarly, [PERSON] et al. [29] reported that performing clean and jerk lifts with a water bag elicited a stronger core training stimulus than using barbells or sandbags of equivalent weight. [PERSON] et al.