Extended Abstract
1.    Introduction
Cardiovascular diseases (CVD), particularly chronic heart failure (CHF), represent a major global public health challenge and remain among the leading causes of mortality and morbidity worldwide. CHF affects over 26 million individuals globally, with its prevalence steadily rising due to aging populations and lifestyle-related risk factors such as hypertension, obesity, diabetes, and physical inactivity. CVD encompasses a broad spectrum of conditions, including coronary artery disease, myocardial infarction, arrhythmias, and peripheral artery disease. Among these, CHF is especially debilitating due to its progressive nature, which leads to fatigue, dyspnea, reduced physical capacity, and a markedly diminished quality of life. One of the less-explored consequences of CHF is its impact on neuromuscular coordination and locomotor function, particularly gait performance. Evidence suggests that individuals with CHF often exhibit abnormal gait patterns due to muscle weakness, balance impairments, early onset of fatigue, and compensatory movement strategies—all of which contribute to an increased risk of falls and further physical decline. Despite the clinical relevance of gait biomechanics in understanding functional limitations in CHF, the routine use of gait analysis in clinical practice remains limited. A comprehensive biomechanical assessment of gait has the potential to detect early signs of functional deterioration and inform personalized rehabilitation strategies. Therefore, the present study aims to examine the differences in gait kinematics and kinetics between patients with CHF and healthy controls, focusing on joint angles and joint moments across multiple planes of motion. These insights may enhance our understanding of functional deficits in CHF and support the development of targeted therapeutic interventions. 
2.    Methods
This case-control study included a total of 40 participants: 20 patients diagnosed with CVD, specifically chronic heart failure (CHF), and 20 age- and BMI-matched healthy controls. The patients (mean age = 53.7 ± 9.5 years; mean BMI = 22.5 ± 4.5) were referred by cardiologists and had confirmed CHF diagnoses based on clinical evaluation and echocardiographic findings. Exclusion criteria were the presence of musculoskeletal disorders, neurological impairments, or any other conditions that could affect gait performance. Gait data were collected using a high-resolution three-dimensional motion capture system (Basler, Germany) operating at 200 Hz with a 7K resolution. Reflective markers were bilaterally placed on key anatomical landmarks following a standardized biomechanical model (e.g., Plug-in Gait). Simultaneously, ground reaction forces were recorded using a Kistler force plate (Kistler, Switzerland) at a sampling frequency of 1000 Hz. Participants performed multiple walking trials on a 10-meter walkway at their self-selected comfortable speed. The most consistent and representative gait cycles were selected for analysis. Kinematic parameters included joint angles and ranges of motion, while kinetic parameters focused on joint torques and ground reaction forces, specifically in the sagittal, frontal, and transverse planes. To maintain consistency, only data from the dominant limb were analyzed. All data were processed and filtered using standard biomechanical protocols. Statistical analyses were performed using SPSS version 23. Independent t-tests were used for normally distributed variables, and Mann–Whitney U tests were applied for non-normally distributed variables. A significance level of p < 0.05 was considered statistically significant.
3.    Results
The findings revealed significant alterations in joint torque patterns among patients with CHF compared to healthy controls. In the sagittal plane, reduced ankle plantarflexion torque during push-off (p = 0.045), decreased knee extension torque (p = 0.010), and diminished hip extension torque at heel contact (p = 0.030) were observed. Frontal plane analysis showed a significant reduction in knee varus torque during early stance (p = 0.021) and hip adduction torque during mid-stance (p = 0.027). In the transverse plane, both knee external rotation torque (p = 0.038) and hip internal rotation torque (p = 0.042) were significantly lower in CHF patients (Fig. 1). Joint range of motion (ROM) was also significantly reduced, particularly in knee flexion during the swing phase (p = 0.002) and in total hip motion (p = 0.005). 

Significant differences in ground reaction forces (GRF) were found only in the sagittal plane, where both mean (p = 0.009) and minimum values (p = 0.011) were higher in patients compared to controls. However, joint stiffness did not show statistically significant differences across all planes, likely due to considerable inter-subject variability and overlapping values. Kinematic analysis indicated relatively higher mean hip angles in the sagittal plane among CHF patients, possibly reflecting a compensatory strategy to maintain propulsion and balance. The observed reductions in hip and knee extensor torques suggest underlying neuromuscular weakness or impaired motor control mechanisms. Overall, gait in CHF patients appeared less efficient and more variable, underscoring the need for comprehensive biomechanical assessment and individualized rehabilitation strategies aimed at addressing functional deficits and enhancing postural stability. 
4.    Discussion
This study demonstrated that chronic heart failure (CHF) significantly affects gait biomechanics. Compared to healthy controls, patients with CHF exhibited marked alterations in joint kinematics, kinetics, joint stiffness, and ground reaction forces (GRFs) across the sagittal, frontal, and transverse planes. In the sagittal plane, significant reductions in ankle plantarflexion and dorsiflexion moments during push-off, along with decreased hip and knee range of motion during the swing phase, indicated impaired propulsion and diminished lower limb functionality. Although differences in joint angles and stiffness in the frontal plane did not reach statistical significance, CHF patients exhibited reduced adduction/abduction moments and limited lateral knee motion. These findings suggest weakness in stabilizing musculature and compromised balance control. In the transverse plane, decreased rotational moments and reduced range of motion at the hip and knee, combined with increased ankle rotational moments, pointed to compensatory strategies aimed at mitigating unwanted rotational instability. Joint stiffness did not differ significantly between groups in any plane. The high inter-subject variability and overlapping standard deviations limited its clinical utility as a discriminative measure. GRF analysis revealed statistically significant differences only in the sagittal plane, particularly in variability and peak loading, underscoring the relevance of this parameter in clinical gait assessment. Notably, CHF patients exhibited increased hip joint angles, elevated ankle rotational moments, and reduced sagittal plane moments at proximal joints. These patterns reflect diminished gait efficiency and heightened postural instability. The findings underscore the importance of a multidimensional gait assessment approach—integrating biomechanical and neuromechanical metrics—and support the development of tailored rehabilitation programs to enhance functional mobility and balance in individuals with CHF.

Ethical Considerations
Compliance with ethical guidelines
There were no ethical considerations to be addressed in this research.
Funding
This research did not receive any financial support from government, private, or non-profit organizations. 
Authors' contributions
All authors contributed equally to preparing the article.
Conflicts of interest
The authors declare that there are no conflicts of interest associated with this article.