Author(s): STEINGRÄBER, T., KLEMM, M., STRAUB, J., KURTZHALS, S., BARNER, P., VELDEMA, J., Institution: BIELEFELD UNIVERSITY, Country: GERMANY, Abstract-ID: 392

INTRODUCTION:
Balance control and sprint performance are key determinants of success in high-performance sports and rely on efficient sensorimotor integration at spinal and supraspinal levels. High-definition trans-spinal direct current stimulation (HD-tsDCS) is a non-invasive method to modulate spinal networks with increased focality and has been shown to influence balance-related sensorimotor control [1,2]. However, its effects on functional performance outcomes relevant to sport remain unclear. This study investigated polarity-dependent effects of HD-tsDCS on balance, sprint performance, and perceived exertion, and examined condition-specific relationships between balance and sprint performance.
METHODS:
In a randomised, double-blinded, placebo-controlled crossover design, 36 participants completed anodal, cathodal, and sham HD-tsDCS sessions applied over the spinal cord at S1, with a minimum washout of 120 hours. Sample size estimation (G*Power; f = 0.25, alpha = .05, power = .80 - 36 participants) indicated sufficient power for a 3x2 repeated-measures ANOVA. Balance (Y Balance Test), sprint performance (Flying 20 m Sprint Test), and perceived exertion (modified RPE scale) were assessed before and after each intervention. Data were analysed using two-way repeated-measures ANOVAs and linear mixed-effects models.
RESULTS:
For the Y Balance Test, the intervention x time interaction was significant (F(1.40,49.04)=7.48, p=.001, eta_p2=.176). Cathodal HD-tsDCS differed from sham (p=.003) and from anodal (p=.013), while anodal did not differ from sham. For sprint performance, the intervention x time interaction was significant (F(1.60,55.97)=6.92, p=.004, eta_p2=.165); anodal differed from cathodal (p=.016), but neither differed from sham. Perceived exertion remained unaffected. Linear mixed-effects modelling showed that the relationship between balance and sprint changes differed by condition (F(2,102)=4.66, p=.012). A significant association between balance improvement and faster sprint times was observed only after anodal HD-tsDCS (b=-0.01, p=.012).
CONCLUSION:
These findings indicate that HD-tsDCS can modulate balance and sprint performance in a polarity-dependent manner without altering perceived exertion. From a performance optimisation perspective, the polarity-specific modulation of balance and the strengthened balance-sprint relationship following anodal HD-tsDCS suggest potential to enhance sensorimotor coordination in performance-critical tasks. HD-tsDCS may represent a promising tool for transiently influencing performance determinants during training or controlled performance settings, warranting further investigation of its efficacy and ethical implications in elite sports.
REFERENCES:
[1] Veldema et al., Bioengineering, 2024
[2] Steingraeber et al., Biomedicines, 2024