Active and sham transcranial direct-current stimulation (tDCS) plus core stability on the knee kinematic and performance of the lower limb of the soccer players with dynamic knee valgus; two armed randomized clinical trial

Hadi Mohammadi Nia Samakosh; Maedeh Maktoubian; Seyyed Pedram Rouhani Doost; Rafael Oliveira; Georgian Badicu; Sameer Badri Al-Mhanna; Mahdieh Hassanzadeh; Peyman Amadekhiar; Reza Rezaeain Vaskasi; Hadi Mohammadi Nia Samakosh; Maedeh Maktoubian; Seyyed Pedram Rouhani Doost; Rafael Oliveira; Georgian Badicu; Sameer Badri Al-Mhanna; Mahdieh Hassanzadeh; Peyman Amadekhiar; Reza Rezaeain Vaskasi

doi:10.3934/Neuroscience.2025017

AIMS Neuroscience

2025, Volume 12, Issue 3: 312-331. doi: 10.3934/Neuroscience.2025017

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Research article

Active and sham transcranial direct-current stimulation (tDCS) plus core stability on the knee kinematic and performance of the lower limb of the soccer players with dynamic knee valgus; two armed randomized clinical trial

1.
Department of Biomechanics and Corrective Exercises and Sports Injuries, University of Kharazmi, Tehran 15719–14911, Iran
2.
Department of Sport Sciences and Health, Faculty of Sport Sciences and Health, University of Tehran 1417935840, Iran
3.
Department of Sports Physiology, Faculty of Physical Education and Sports Sciences, University of Mazandran 1353447416, Babolsar, Iran
4.
Santarém Polytechnic University, School of Sport, Rio Maior 2040–413, Portugal & Research Center in Sport Sciences, Health Sciences and Human Development (CIDESD), Santarém Polytechnic University, Rio Maior 2040–413, Portugal
5.
Department of Physical Education and Special Motricity, Faculty of Physical Education and Mountain Sports, Transilvania University of Braşov, Braşov, 500068, Romania
6.
Center for Global Health Research, Saveetha Medical College and Hospitals, Saveetha Institute of Medical and Technical Sciences, University of Saveetha, Chennai 602105, India
7.
Department of Elementary Education, Faculty of Hazrat Fatemeh Al-Zahra, Farhangian University of Ghaemshahr 1998963341, Mazandaran, Iran
8.
Department of Corrective Exercises and Sports Injuries, Faculty of Sport Sciences, University of Shomal 4616184596, Mazandaran, Iran

Received: 17 May 2025 Revised: 30 June 2025 Accepted: 09 July 2025 Published: 21 July 2025

Dynamic knee valgus (DKV) is a prevalent risk factor for anterior cruciate ligament (ACL) injuries in soccer players, particularly during noncontact mechanisms. Transcranial direct-current stimulation (tDCS) and core stability exercises have shown promise in enhancing motor control and biomechanical alignment, but their combined effects on DKV remain unexplored. This study aimed to evaluate the efficacy of active versus sham tDCS combined with core stability exercises on knee kinematic alignment and lower limb performance in young male soccer players with DKV. In this double-blind, randomized controlled trial, 42 male soccer players (aged 18–25 years) with DKV were randomly assigned to either an active tDCS group (n = 21) or a sham tDCS group (n = 21). Both groups underwent 8 weeks of core stability exercises (3 sessions/week, 30 minutes/session) preceded by 15 minutes of active (2 mA) or sham tDCS targeting the primary motor cortex (M1). The primary outcome was the frontal plane projection angle (FPPA) during a single-leg landing task, measured using 2D video analysis. Secondary outcomes included vertical jump height and 8-hop test time. Outcomes were assessed at baseline and post-intervention. A 2 × 2 mixed-model ANOVA with Bonferroni-corrected post hoc tests was used for statistical analysis via SPSS₂₇. The active tDCS group showed significantly greater improvements in FPPA (+5.65% vs. +2.26%, p < 0.001, ηp² = 0.82), vertical jump height (+25.30% vs. +10.45%, p < 0.001, ηp² = 0.75), and 8-hop test time (−21.05% vs. −14.27%, p < 0.001, ηp² = 0.68) compared to the sham group. Both groups improved from baseline, but the active tDCS group exhibited larger effect sizes across all outcomes. Active tDCS combined with core stability exercises significantly enhanced knee kinematic alignment and lower limb performance in soccer players with DKV compared to sham tDCS. These findings suggest that neuromodulation, when paired with targeted exercise, is a promising strategy for injury prevention and performance enhancement in athletes. Further research is needed to explore long-term effects and applicability to diverse populations.
- dynamic knee valgus,
- transcranial direct-current stimulation,
- core stability,
- knee kinematics,
- soccer,
- injury prevention
Citation: Hadi Mohammadi Nia Samakosh, Maedeh Maktoubian, Seyyed Pedram Rouhani Doost, Rafael Oliveira, Georgian Badicu, Sameer Badri Al-Mhanna, Mahdieh Hassanzadeh, Peyman Amadekhiar, Reza Rezaeain Vaskasi. Active and sham transcranial direct-current stimulation (tDCS) plus core stability on the knee kinematic and performance of the lower limb of the soccer players with dynamic knee valgus; two armed randomized clinical trial[J]. AIMS Neuroscience, 2025, 12(3): 312-331. doi: 10.3934/Neuroscience.2025017

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Abstract

Dynamic knee valgus (DKV) is a prevalent risk factor for anterior cruciate ligament (ACL) injuries in soccer players, particularly during noncontact mechanisms. Transcranial direct-current stimulation (tDCS) and core stability exercises have shown promise in enhancing motor control and biomechanical alignment, but their combined effects on DKV remain unexplored. This study aimed to evaluate the efficacy of active versus sham tDCS combined with core stability exercises on knee kinematic alignment and lower limb performance in young male soccer players with DKV. In this double-blind, randomized controlled trial, 42 male soccer players (aged 18–25 years) with DKV were randomly assigned to either an active tDCS group (n = 21) or a sham tDCS group (n = 21). Both groups underwent 8 weeks of core stability exercises (3 sessions/week, 30 minutes/session) preceded by 15 minutes of active (2 mA) or sham tDCS targeting the primary motor cortex (M1). The primary outcome was the frontal plane projection angle (FPPA) during a single-leg landing task, measured using 2D video analysis. Secondary outcomes included vertical jump height and 8-hop test time. Outcomes were assessed at baseline and post-intervention. A 2 × 2 mixed-model ANOVA with Bonferroni-corrected post hoc tests was used for statistical analysis via SPSS₂₇. The active tDCS group showed significantly greater improvements in FPPA (+5.65% vs. +2.26%, p < 0.001, ηp² = 0.82), vertical jump height (+25.30% vs. +10.45%, p < 0.001, ηp² = 0.75), and 8-hop test time (−21.05% vs. −14.27%, p < 0.001, ηp² = 0.68) compared to the sham group. Both groups improved from baseline, but the active tDCS group exhibited larger effect sizes across all outcomes. Active tDCS combined with core stability exercises significantly enhanced knee kinematic alignment and lower limb performance in soccer players with DKV compared to sham tDCS. These findings suggest that neuromodulation, when paired with targeted exercise, is a promising strategy for injury prevention and performance enhancement in athletes. Further research is needed to explore long-term effects and applicability to diverse populations.

Acknowledgments

We express our sincere gratitude to all individuals who provided financial support for this research. This study was not funded by any institution. Rafael Oliveira is a research member of the Research Center in Sports Sciences, Health and Human Development (CIDESD) which was funded by National Funds by FCT – Foundation for Science and Technology under the following project UID/04045.

Conflict of interest

The authors declare no conflict of interest.

Authors' contributions

HMNS and MH planned the study; RRV, GB, RO and MM conducted the investigation and drafted the first version of the manuscript; SBAM, HMNS, and GB reviewed the methodology; HMNS, MM, MH, GB, RRV, PA, and SPRD contributed to data interpretation; HMNS, RRV, MM, RO, SBAM, and MH revised the manuscript critically. All authors approved the final version of the manuscript.

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