نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Extendrd Abstract
Background and Aim: Stroke is one of the most common causes of physical disability worldwide, resulting in lower limb muscle weakness, impaired balance, reduced mobility, and an increased risk of falling. These impairments, particularly in patients with chronic ischemic stroke, often lead to decreased quality of life and functional independence. Therefore, rehabilitation in such patients requires approaches that are both safe and highly effective. Aquatic exercises have been introduced as a promising method in the rehabilitation of neurological patients due to the unique characteristics of the aquatic environment, including reduced joint loading, enhanced, multidirectional resistance, and improved proprioceptive stimulation.
Despite the growing body of evidence supporting aquatic rehabilitation, limited attention has been paid to the influence of water depth on the effectiveness of aquatic exercise interventions. Previous studies suggest that water depth may affect muscle activation patterns, movement mechanics, energy expenditure, and ultimately the therapeutic outcomes of exercise programs. Accordingly, the aim of the present study was to examine and compare the effects of aquatic training at two different depths (shallow and deep water) on lower limb muscle strength and functional balance in male patients with chronic ischemic stroke.
Materials and Methods: This quasi-experimental study employed a pretest–posttest design with a control group. The study population consisted of men with chronic ischemic stroke in Rafsanjan, Iran. Thirty-six participants (60.70 ± 6.20 years) who met the inclusion criteria were recruited and randomly assigned, using stratified randomization based on age and Berg Balance Scale (BBS) scores, into three groups: shallow-water exercise, deep-water exercise, and control (n=12 per group). The inclusion criteria were as follows: a neurologist-confirmed diagnosis of first-ever ischemic stroke; a post-stroke duration of 6 months to 2 years; lower-extremity muscle strength ranging from 3.5 to 5.5 on the Medical Research Council (MRC) scale; a Mini-Mental State Examination (MMSE) score of ≥23; a BBS score between 21 and 44; the ability to stand independently for at least 5 minutes; and the ability to walk for at least 10 minutes with or without an assistive device. Participants were excluded if they had uncontrolled medical conditions, additional neurological or musculoskeletal disorders, unstable cardiovascular or respiratory diseases, a history of major central nervous system surgery, or missed more than three training sessions.
The intervention consisted of a 6-week aquatic exercise program conducted three times per week, with each session lasting 60 minutes. The exercises program included hip flexion, extension and abduction, multidirectional walking, hip rotation with knee flexion, scissors movements, and single-leg standing. Each session consisted of a 5-minute warm-up, 50 minutes of exercise training, and a 5-minute cool-down period. Training volume progressed gradually from two sets of three repetitions to three sets of ten repetitions throughout the intervention period. Exercises were performed at the level of the anterior superior iliac spine in the shallow-water group and at the level of the xiphoid process in the deep-water group. The control group did not receive any intervention during the study period.
Balance and lower limb muscle strength were assessed using the Berg Balance Scale (BBS) and the Medical Research Council (MRC) scale, respectively, before and after the intervention. Data were analyzed using the Shapiro–Wilk test, Levene’s test, one-way analysis of variance (ANOVA), and mixed-design ANOVA. Bonferroni post hoc tests and partial eta squared (η²) values were used to examine pairwise differences and estimate effect sizes. Statistical analyses were performed using SPSS version 22, with the significance level set at p≤0.05
Findings: One-way ANOVA results showed no significant differences among the three groups at baseline with respect to balance (F(2,27)=0.71, p=0.50) and lower limb muscle strength (F(2,27)=0.17, p=0.84). The mixed ANOVA results indicated a significant time×group interaction effect for balance (F(2,27)=115.63, p=0.0001) and muscle strength (F(2,27)=47.88, p=0.0001). Bonferroni-adjusted pairwise comparisons showed that participants in both the shallow-water and deep-water exercise groups demonstrated significant improvements in balance and lower limb muscle strength from pretest to posttest (p<0.001 for both groups). In contrast, no significant changes were observed in the control group (p=0.99). Furthermore, posttest comparisons revealed that both aquatic exercise groups achieved significantly higher scores in balance and lower limb muscle strength than the control group (p<0.001). However, no significant differences were found between the shallow-water and deep-water exercise groups in either outcome measure (p=0.90) (Figure 1).
Conclusion: The findings of the present study demonstrated that six weeks of aquatic exercise performed in either shallow or deep water significantly improved lower-extremity muscle strength and balance in patients with chronic ischemic stroke.These results suggest that aquatic exercise provides a favorable environment for enhancing motor function in this population. The aquatic environment likely facilitates functional movement by reducing effective body weight and decreasing joint loading, thereby allowing movements to be performed more safely and confidently. In addition, the uniform resistance of water continuously challenges the lower-extremity muscles throughout exercise, contributing to improvements in muscular strength.
The observed improvements in balance may also be explained by the sensory and mechanical properties of the aquatic environment. Hydrostatic pressure and water turbulence increase stimulation of sensory receptors and enhance sensorimotor feedback, which may improve postural control and balance performance. Furthermore, repeated practice of movements in an environment that requires continuous postural adjustments to external perturbations may promote neuromuscular adaptations and improve motor coordination. Increased lower-extremity muscle strength itself is also an important determinant of balance, and part of the observed improvement in balance may have occurred through this mechanism.
A notable finding of the present study was the lack of significant differences between the shallow-water and deep-water exercise groups. This finding suggests that the therapeutic benefits of aquatic exercise in patients with chronic ischemic stroke may depend more on regular participation in aquatic-based training than on the depth of water immersion. Immersion at hip level appears sufficient to reduce mechanical loading and facilitate functional movement, whereas increasing immersion depth to chest level does not seem to provide additional benefits for improving muscle strength or balance. Therefore, both immersion depths may be equally effective for promoting functional adaptations in this population.
Several limitations should be acknowledged when interpreting these findings. First, the sample consisted exclusively of patients with chronic ischemic stroke who met specific inclusion criteria, which may limit the generalizability of the results to other stroke populations. Second, no follow-up assessment was conducted to evaluate the long-term retention of the training effects. Finally, only two levels of water immersion were examined. Future studies are encouraged to investigate a wider range of immersion depths, include long-term follow-up assessments, and evaluate the effectiveness of aquatic exercise in more diverse stroke populations.
Ethical Considerations: This study was approved by the Ethics Committee of Rafsanjan University of Medical Sciences under the code IR.RUMS.REC.1396.207. All participants were informed about the study procedures and provided written informed consent.
Compliance with Ethical Guidelines: The study was conducted in accordance with the ethical principles of the Declaration of Helsinki and the approved institutional guidelines. Participation was entirely voluntary, and the confidentiality of participants’ information was maintained throughout all stages of the research.
Funding: This study did not receive any financial support from internal or external sources.
Conflicts of Interest: The authors declare that there are no scientific or financial conflicts of interest related to the conduct or publication of this research.
کلیدواژهها English
