نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه رازی، کرمانشاه، ایران
2 گروه فیزیولوژی ورزشی، دانشکده علوم ورزشی دانشگاه رازی، کرمانشاه، ایران
3 گروه علوم ورزشی، دانشگاه آزاد اسلامی واحد سنندج، سنندج، ایران
4 دانشکده حرکت شناسی، دانشگاه کلگری، کلگری، آلبرتا، کانادا
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Purpose: Postural control is essential for maintaining balance and safely performing daily, particularly athletic activities. This issue is even more in mountaineering, as exposure to altitude may impair postural control. Furthermore, transcranial Direct Current Stimulation (tDCS) has been proposed as a non-invasive and attractive method for modulating postural control. However, limited evidence is available regarding the effect tDCS on postural control following endurance exercise under hypoxic conditions. This study aimed to compare the effects of single-site and dual-site tDCS on postural control in female mountaineers following endurance exercise under normobaric hypoxia.
Materials and Methods: In this randomized, double-blind, crossover study, twelve active female mountaineers aged 18–44 years participated. Each participant received four separate conditions: anodal stimulation of the primary motor cortex (M1), anodal stimulation of the left dorsolateral prefrontal cortex (DLPFC), dual-site anodal M1-DLPFC stimulation, and sham stimulation. The sessions were conducted at intervals of at least one week. The order of the experimental conditions was randomized for each participant, and the sessions were conducted at intervals of at least one week. At the beginning of each session, center of pressure (CoP) indices as parameters of postural control, including CoP ellipse area, CoP path length, anterior-posterior standard deviation of CoP displacement (SD-AP), and mediolateral standard deviation of CoP displacement (SD-ML), were recorded using a PT-Scan system. Participants were then exposed to normobaric hypoxia conditions (FiO₂ = 13%) for 30 minutes and, after receiving 20 minutes of brain stimulation at an intensity of 2 mA, performed a 20-km endurance time trial using cycle ergometer. Immediately after the endurance exercise and under the same hypoxic conditions, post-test measurements were performed in the same manner as the pre-test measurements. After checking the statistical assumptions, data were analyzed using repeated-measures analysis of variance and paired-samples t-tests. Significance level was set at p < 0.05.
Results: Following endurance exercise under normobaric hypoxia, the CoP ellipse area showed a significant deterioration in the M1 (p = 0.011) and sham (p = 0.027) conditions. However, no significant changes were observed in the DLPFC (p = 0.279) and M1-DLPFC (p = 0.508) conditions. For CoP path length, a significant deterioration was observed across all conditions (p < 0.05). The anterior-posterior standard deviation of CoP displacement (SD-AP) did not change significantly in any condition. The mediolateral standard deviation of CoP displacement (SD-ML) significantly deteriorated in the sham (p = 0.001), M1-DLPFC (p = 0.003), and M1 (p = 0.021) conditions, but not in the DLPFC condition (p = 0.084).
Conclusion: The findings of the present study indicate that postural control parameters deteriorated following endurance exercise under hypoxic conditions in female mountaineers. The application of tDCS over the M1 area did not appear to exert a protective effect against this deterioration. However, dual-site stimulation over the M1-DLPFC regions, and particularly over the DLPFC, may help prevent the deterioration of some postural control parameters.
کلیدواژهها [English]
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