Effect of transcranial direct current stimulation on human single-leg landing stability
Lin Qinzhao1, Wei Mengli1, 2, Zhong Yaping1, 2, Wu Qian1, Zhou Botao1, Wang Haifeng1
1Sports Big Data Research Center of Wuhan Sports University, Wuhan 430079, Hubei Province, China; 2Hubei Sports and Health Innovation and Development Research Center, Wuhan 430079, Hubei Province, China
Abstract: BACKGROUND: Transcranial direct current stimulation (tDCS), as a non-invasive brain stimulation technique, can enhance human muscle strength or improve single-leg landing stability instantly, but no relevant research has demonstrated this yet.
OBJECTIVE: To investigate the effect of tDCS on the stability of single-leg landings in human subjects.
METHODS: Male undergraduate students from Wuhan Sports University were recruited as study participants. They were divided into two groups, A (n=6) and B (n=5), using a random number table. Group A underwent a sham stimulation session followed by a 3-day washout period, after which they received tDCS. Conversely, Group B received tDCS initially, followed by a 3-day washout period, and subsequently underwent the sham stimulation session. Following the respective stimulation sessions, an immediate single-leg landing test was administered to assess and collect biomechanical parameters. Data resulting from the tDCS intervention were aggregated and analyzed as the experimental group dataset, whereas data stemming from the sham stimulation were consolidated as the control group dataset.
RESULTS AND CONCLUSION: Regarding core stability, the tDCS intervention showed a significant interaction with landing height on the maximal trunk flexion angle (P < 0.05). A paired comparison of the data showed a significant decrease in the maximum trunk flexion angle following true stimulation compared to sham stimulation at a 30-cm landing height. Additionally, the tDCS intervention had a significant main effect on the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity (P < 0.05). Following true stimulation, there was a significant decrease in the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity compared to sham stimulation. In terms of lower limb joint stability, the tDCS intervention had a significant main effect on the maximum dynamic ankle valgus angle (P < 0.05). This resulted in a significant decrease in the angle following true stimulation compared to sham stimulation. In addition, the tDCS intervention had a significant main effect on the peak muscle activation of the lateral head of the gastrocnemius lateralis (P < 0.05). This showed a significant increase after true stimulation compared to sham stimulation. An interaction between the tDCS intervention and landing height was observed for the peak muscle activation of the tibialis anterior (P < 0.05). Paired comparison analyses revealed a significant increase in muscle activation after true stimulation specifically at a 60-cm landing height. Regarding center of pressure stability, there were no significant interactions or main effects of the tDCS intervention on the mean lateral displacement, mean lateral displacement velocity, mean anterior-posterior displacement, or mean anterior-posterior displacement velocity at the center of pressure (P > 0.05). Furthermore, the tDCS intervention had no significant main effects on any of the center of pressure indicators (P > 0.05). In conclusion, tDCS can immediately improve core stability and lower limb joint stability during single-leg landing, making it an effective warm-up technique for improving single-leg landing stability and reducing the risk of lower limb injuries.
Key words: transcranial direct current stimulation, stability, single-leg landing, body control, muscle activation, core stability, lower limbs