# Acute Effects of Whole-Body Vibration on Gait Kinematics in Individuals with Parkinson's Disease
## 1 Introduction  
Parkinson's disease (PD) is a common neurodegenerative disorder affecting motor functions and leading to symptoms like tremor, rigidity, bradykinesia, and postural instability [1]. These motor impairments significantly influence gait, with reduced foot clearance, gait speed, stride length, and increased trunk inclination [2]. Moreover, gait impairments lead to an increased risk of falls, with PD individuals being nine times more likely to experience recurrent falls and five times more likely to sustain fall-related injuries compared to healthy individuals [3]. This functional decline is attributed to disruptions in the neural mechanisms that coordinate movement and balance exacerbating the challengeof managing the disease [4]. The scoping review by [PERSON] et al. [5] emphasizes the critical role of biomechanical gait analysis in characterizing [PERSON]'s disease progression and rehabilitation strategies. Clinically, improvements in neuromuscular coordination, motor unit synchronization, and postural stability are essential to improve gait performance in patients with [PERSON]'s disease. These biomechanical and neuromuscular adaptations can lead to improved gait efficiency, increased gait cadence, and reduced instability, which collectively contribute to improved functional mobility and reduced risk of falls. Therefore, therapeutic interventions targeting these mechanisms, such as whole-body vibration, are promising for improving gait safety and overall quality of life in this population. Parkinson's disease is typically assessed using a combination of standardized clinical scales and diagnostic criteria. The Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is the most widely used and validated tool for comprehensive assessment of both motor and non-motor symptoms in PD. The MDS-UPDRS consists of four parts: non-motor experiences of daily living, motor experiences of daily living, motor examination, and motor complications. It has demonstrated high internal consistency, reliability, and validity for rating the severity and progression of PD [6; 7]. Another commonly used tool is the Hoehn and Yahr (HY) staging scale, which provides a simple and widely accepted method to stage the severity of PD based on motor impairment and functional disability. The HY scale correlates well with other standardized scales and with neuroimaging findings of dopaminergic loss, although it is less sensitive to subtle clinical changes [8]. Levodopa remains the primary pharmacological treatment, but long-term use can lead to motor fluctuations and side effects [9]. Consequently, complementary therapies like physical exercise (PE) and whole-body vibration (WBV) have been investigated as potential adjuvant treatments. PE has been shown to benefit both physical and psychological health by supporting neurogenesis, synaptogenesis, and angiogenesis in PD [10; 11]. WBV stimuli, which involve exposing the body to mechanical vibrations, demonstrated positive effects on physical fitness in individuals with PD [12; 13]. Indeed, in skeletal muscles, acute WBV stimuli induce tonic reflex contractions in the agonist muscles while relaxing the antagonists, contributing to improved motor function and enhanced muscle strength, balance, and proprioception [14; 15; 16]. Studies have shown that chronic exposure to WBV improves gait speed and balance in individuals with PD. For instance, [PERSON] et al. [17] reported that WBV training increased walking speed and quality of life in individuals with PD. Similarly, [PERSON] et al. [12] showed that WBV (at 25 Hz and amplitude of 7-14 mm) combined with conventional physiotherapy improved balance and gait in individuals with PD. A recent meta-analysis by [PERSON] et al. [18] confirmed the efficacy of WBV in enhancing gait performance in PD. Despite these promising findings on the chronic effects of WBV, the acute effects of WBV in this population remain less explored.