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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.
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ObjectiveTo investigate the difference in bilateral lower limb muscle synergy mode during gait in patients after unilateral anterior cruciate ligament reconstruction. MethodsElectromyography from bilateral lower limb muscles during gait were collected from twelve male and eight female patients after unilateral anterior cruciate ligament reconstruction in Affiliated Hospital of Wuhan Sports University, from April to June, 2023. The data were analyzed using non-negative matrix decomposition algorithm to extract the number of muscle synergies in the affected and unaffected legs, the time to peak activation of muscle synergies and the relative weights of the muscles. ResultsSix types of muscle synergy were identified in the unaffected leg of males during gait, while five types were identified in the affected leg, lacking synergy 2 that mainly from the tibialis anterior muscle. Six types of muscle synergy were identified in both legs in females during gait. There was no significant difference in the time to peak activation of muscle synergies between both legs in males (P > 0.05). However, the time to peak activation of muscle synergies increased in females in the affected leg for synergy 3 and synergy 5 (P < 0.05). The relative weight of the rectus femoris was lower in synergy 1 in the affected leg in males (P < 0.05). For female, the relative weight of the vastus lateralis was higher and the relative weight of the biceps femoris was lower in synergy 2 in the affected leg in females (P < 0.05); while the relative weight of the rectus femoris was lower in synergy 3 (P < 0.05), and the relative weight of the biceps femoris was lower in synergy 6 (P < 0.05). ConclusionMales would freeze the muscle synergy dominating ankle dorsiflexion in affected leg to enhance ankle stability, and reduce the relative weight of rectus femoris during the loading response phase to weaken the knee landing cushioning. However, females would delay the activation of synergies dominating in loading response phase and the mid-stance phase, enhance the relative weight of vastus lateralis during the loading response phase, and reduce the relative weights of rectus femoris in the loading response phase and the relative weight of biceps femoris in the mid-stance phase, to limit knee flexion.
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Objective To evaluate the relationship between stenosis of intra- or extra-cranial cerebral large artery and capsular warning syndrome(CWS). Methods Eleven consecutive CWS patients hospitalized during period of time from November 2008 to December 2009 were retrospectively analyzed.Result In these 11 patients with CWS, 5 patients had motor symptoms only, 4 patients had pure sensory symptoms, and 2 patients had sensorimotor symptoms. Ten patients underwent cervical contrast-enhanced MRA and intracranial MRA examination. The results showed no sign of arterial stenosis. Seven CWS patients eventually had strokes, 1 progressed to stroke despite receiving the therapy of antiplatelet and anticoagulation. All stroke lesions were located in the capsula interna. All the CWS patients had vascular risks: 7 were smoker, 8 had hypertension, 1 had diabetes mellitus, and 5 had hyperlipidemia. One patient had a history of previous stroke; no patient had a history of ischemic heart disease or atrial fibrillation. At follow-up(10. 2 ±3.4)mouths, the average modified Rankin scale score for all patients was 0. 73 ± 1.20.Conclusion CWS was not associated with stenosis of the intra and extra-cranial large cerebral arteries.CWS may be associated with small-vessel single-penetrator disease.