Effects Of Bilateral Extracephlic Transcranial Direct Current Stimulation On Lower Limb Kinetics In CMJ

Effects of Bilateral Extracephalic Transcranial Direct Current Stimulation on Lower Limb Kinetics in Countermovement JumpsAbstract OBJECTIVE: Transcranial direct current stimulation (tDCS) is an effective method for improving sports/exercise performance in humans. However, studies examining the effects of tDCS on jumping performance have reported inconsistent findings, and there is a paucity of studies investigating the effects of tDCS on lower limb energy and kinetics in countermovement jumps (CMJs). Thus, we investigated the effects of tDCS on countermovement jump (CMJ) performance and analysed kinetic variations in the ankle, knee, and hip joints. METHODS: In total, 15 healthy young participants randomly received anodal or sham bilateral stimulation of the primary motor cortex (M1). The bilateral tDCS (Bi-tDCS) montage used an intensity of 2 mA for a 20 min monophasic continuous current. Jump height, energy, and lower limb kinetic data in CMJs were collected at pre-stimulation (Pre), post-0 minutes (Post-0), and post-30 minutes (Post-30) using a motion capture system and two 3D force plates. Jump height, lower extremity energy, and kinetic variables in CMJs were analysed with two-way repeated-measures ANOVA. RESULTS: Jump height was significantly increased at Post-0 and Post-30 compared to that at Pre and at Post-0 compared to that in the sham condition (P < 0.05). Total net energy of the lower limbs was significantly increased at Post-30 relative to that at Pre (P < 0.05). Ankle positive energy and net energy was significantly decreased at Post-0 and Post-30 compared to that at Pre in the sham condition (P < 0.05). Maximum knee power was significantly increased at Post-0 and Post-30 relative to that in Pre- and sham conditions (P < 0.05). Regardless of timepoint, maximum hip torque was higher in the tDCS condition than in the sham condition. Maximum ankle torque at Post-30 was significantly decreased compared to that at Pre and Post-0 (P < 0.05) in both stimulation conditions. CONCLUSION: Bi-tDCS is an effective method for improving jump height by modulating ankle and knee net energy. The net energy improvement of the lower extremities may be due to variation in the kinetic chain resulting from tDCS-enhanced knee exploration force and hip maximum strength in CMJs. The effects of Bi-tDCS decrease gradually.