Document Type : Scientific Research

Authors

• amir hamzeh sabzi ¹
• farnaz torabi ¹
• Aliyeh Amini Khanavandi ²

¹ Department of Physical Education, Payame Noor University, Tehran, Iran

² M.A Student in Physical Education, Payam Noor University, Tehran, Iran

Abstract

Objective: Aging is an inevitable biological process accompanied by extensive physiological and structural changes across multiple body systems (Ahmadi et al., 2017; Migliore et al., 2024). With the growing population of individuals aged 60 years and older worldwide and in Iran, maintaining functional independence and enhancing quality of life among older adults has become a major public health priority (Ahmadi et al., 2017). One of the principal barriers to preserving physical independence in this population is the age-related decline in sensory integration systems, including the somatosensory, visual, and vestibular systems, which contributes to progressive deterioration in functional capacity, reduced physical activity, and an increased risk of falls (Zhang et al., 2022). Motor performance is a multidimensional construct that reflects the integrity of the musculoskeletal and neuromuscular systems and encompasses four primary components: flexibility, static balance, dynamic balance, and muscular strength (Holland et al., 2002). Age-related reductions in flexibility can impair the efficient performance of activities of daily living (Holland et al., 2002), whereas deficits in dynamic balance are strongly associated with accidental falls, the leading cause of injury-related mortality among adults aged over 65 years (World Health Organization, 2007). Likewise, the gradual loss of lower-limb muscle strength, known as dynapenia, compromises the ability to generate rapid corrective contractions required to restore balance following slips or perturbations (Mitchell et al., 2012). Lower-extremity weakness is recognized as one of the most important modifiable risk factors for falls (CDC, 2023). The vestibular system serves as a central regulator of postural stability by activating vestibulospinal pathways responsible for maintaining antigravity muscle tone (Han, 2021). According to the sensory reweighting theory, systematic vestibular stimulation can enhance the efficiency of the central nervous system in dynamically processing sensory inputs and generating more effective neuromuscular responses (Peterka, 2002). Despite well-established evidence supporting the beneficial effects of physical exercise on balance (McDonnell & Hillier, 2015; Kanyılmaz et al., 2022), the effectiveness of targeted vestibular interventions on all dimensions of motor performance in sedentary older adults without clinical vestibular pathology remains unclear. Previous studies have primarily focused on multicomponent exercise programs, making it difficult to isolate the specific contribution of sensory-based training (Sabzi et al., 2022; Labata-Lezaun et al., 2023). Therefore, the present study aimed to investigate the effects of a vestibular stimulation training program on motor performance components in older women. Method:  This study employed a quasi-experimental pretest–posttest design with a control group. The study population consisted of sedentary women aged 60–75 years residing in Qom, Iran. Thirty eligible volunteers (mean age = 66 ± 5.4 years) provided written informed consent and were randomly assigned to either an experimental group (n = 15) or a control group (n = 15). The experimental group participated in a four-week vestibular stimulation training program consisting of three sessions per week (12 sessions, 60 minutes each). The intervention was structured into three phases: gaze stabilization, postural stability, and dynamic balance. Training complexity was progressively increased according to individual advancement by gradually modifying support surfaces (from firm ground to foam and trampoline surfaces) and manipulating visual input (eyes closed). The control group continued their usual daily activities. Data were analyzed using analysis of covariance (ANCOVA) with the significance level set at p<0.05. Results:  Descriptive findings indicated improvements in all motor performance variables in the experimental group at posttest.After adjustment for baseline scores, the between-group difference in static balance was statistically significant (F_1,27 = 14.27, p < 0.001), with the vestibular training program accounting for 24% of the variance in static balance performance. A significant between-group difference was also observed in dynamic balance (F_1,27 = 8.75, p < 0.05), with vestibular stimulation explaining 21% of the observed improvement. The effect of group on muscular strength remained significant after controlling for baseline values (F_1,27 = 5.74, p < 0.05), with 23% of the variance in strength gains attributable to the intervention. Similarly, a significant difference was found between groups in posttest flexibility scores (F_1,27 = 4.21, p < 0.05), and vestibular stimulation training explained 17% of the variance in flexibility. Conclusion: The significant improvements in balance outcomes are consistent with the findings of McDonnell and Hillier (2015) and Hall et al. (2022), who identified vestibular rehabilitation as an effective approach for enhancing postural stability. Furthermore, Meng et al. (2023) reported that vestibular training improves dynamic balance through the enhancement of vestibulo-ocular and vestibulospinal reflexes. The physiological mechanism underlying these adaptations can be attributed to central compensation and reflex retraining processes, whereby head and trunk movements combined with visual challenges promote sensory reweighting and more efficient utilization of vestibulospinal pathways (Peterka, 2002; van der Scheer-Horst et al., 2014). The observed improvements in muscular strength are consistent with the findings of Karimzadeh Ardakani et al. (2020) and Concha-Cisternas et al. (2023). Although Granacher et al. (2012) and Wolfson (1996) suggested that static balance exercises exert minimal effects on maximal strength because of their low mechanical loading, the strength gains observed in the present study may be attributed to the dynamic nature of the protocol and the repeated eccentric contractions of antigravity muscles involved in postural adjustments. Improvements in flexibility were also in agreement with the findings of Emilio et al. (2014), as vestibular stimulation enhances trunk muscle stability (Takakusaki, 2017) and increases movement confidence by reducing fear of falling, thereby enabling older adults to achieve greater ranges of motion without excessive muscular guarding (Hall et al., 2022).Overall, a vestibular stimulation training program appears to be an effective and multifaceted intervention for improving functional physical fitness in sedentary older women through mechanisms of neuroplasticity and sensory reweighting. The program simultaneously enhances postural stability, lower-limb strength, and flexibility. From a practical perspective, this low-cost and scalable protocol requires no sophisticated equipment and can be implemented in residential care facilities or as a home-based exercise program to promote functional independence and reduce the economic burden associated with falls among older adults (Hall et al., 2022).

Keywords

• Vestibular Stimulation
• Static Balance
• Dynamic Balance
• Functional Strength
• Flexibility
• Older Women

Main Subjects

• A