The effect of transcranial direct current stimulation on bilateral asymmetry and joint angles of the lower limb for females when crossing obstacles | BMC Sports Science, Medicine and Rehabilitation

Gait bilateral asymmetry decreased after tDCS during crossing higher obstacles

Gait bilateral asymmetry parameter values were shown in Fig. 2. There were no significant interaction between condition*height in left/right Stride length GA (Fig. 2a) (all, P > 0.305) and left/right DS time GA (Fig. 2d) (all, P > 0.278) between tDCS and sham-tDCS condition at 30%, 20%, 10% leg’s length obstacle height. However, left/right Swing time GA (P = 0.046, P = 0.038, respectively), left/right Stance time GA (all, P < 0.035), left/right SW/ST GA (all, P < 0.005) showed significant differences between condition and height interaction effects. Differences between sham-tDCS and tDCS conditions in Swing time GA (Fig. 2b), Stance time GA (Fig. 2c) and SW/ST GA (Fig. 2e) at three obstacle crossing heights were found (all P < 0.05). Compared with the sham-tDCS condition, the tDCS condition showed a significantly decreased in Swing time GA (Left: P_30%=0.002, P_20%=0.005, ES varying from 0.71 to 0.80; Right: P_30%<0.001, P_20%=0.002, ES varying from 0.78 to 1.04, respectively), Stance time GA (Left: P_30%=0.001, P_20%=0.003, ES varying from 0.76 to 0.83; Right: P_30%=0.002, P_20%=0.003, ES varying from 0.78 to 0.82, respectively) at 30% and 20% leg’s length obstacle heights but not with 10% leg’s length. Specifically, the SW/ST GA (Left: P_30%<0.001, P_20%<0.001, P_10%=0.021, ES varying from 0.56 to 1.38; Right: P_30%<0.001, P_20%<0.001, p_10%=0.045, ES varying from 0.48 to 1.40, respectively) of tDCS condition decreased significantly at 30%, 20% and 10% leg’s length obstacle height.

The parameters of gait asymmetry at tDCS condition and sham-tDCS condition among three obstacle crossing height. “*” indicates significant interaction effects; “†” indicates significant main effects between tDCS and sham-tDCS; “‡” indicates significant height main effects among different leg’s length; “§” indicates significant differences between tDCS and sham-tDCS treatment at each height. (L: Left/R: Right: left and right limb, respectively, as leading limb during obstacle crossing; 30, 20, 10LL: 30%, 20% and 10% leg’s length obstacles height; SW: swing time, ST: stance time, SW/ST: swing/stance time, DS: double support time, GA: gait asymmetry)

Maximum joint angles decreased after tDCS during crossing higher obstacles

Furthermore, leading and trailing limb maximum joint angles parameter values were shown in Fig. 3, an interaction effect was found between condition*height in left/right ankle (all, P < 0.025), left/right hip (all, P < 0.033); left/right knee (all, P < 0.048) of leading limb, left/right hip (all, P < 0.005), left/right knee (all, P < 0.029) of trailing limb, however, no significant interaction effect between condition*height was found for left/right ankle joint (Fig. 3b) when trailing limb crossed obstacles. Ankle joint angles (Fig. 3a), knee joint angles (Fig. 3c), hip joint angles (Fig. 3e) of leading limb and knee joint angles (Fig. 3d), hip joint angles (Fig. 3f) of trailing limb showed differences when compared sham-tDCS and tDCS condition. Specifically, ankle (Left: P_30%=0.034, P_20%=0.001, ES varying from 0.51 to 0.89; Right: P_30%=0.036, P_20%<0.001, ES varying from 0.50 to 1.01, respectively), knee (Left: P_30%<0.007, P_20%<0.001, ES varying from 0.67 to 1.18; Right: P_30%=0.001, P_20%=0.001, ES varying from 0.90 to 0.92, respectively), hip (Left: P_30%<0.001, P_20%=0.009, ES varying from 0.65 to 1.34; Right: P_30%=0.001, P_20%=0.002, ES varying from 0.79 to 0.89, respectively) joint angles of leading limb and knee (Left: P_30%=0.001, P_20%<0.001, ES varying from 0.84 to 1.03; Right: P_30%<0.001, P_20%<0.001, ES varying from 0.99 to 1.05, respectively), hip (Left: P_30%<0.001, P_20%<0.001, ES varying from 1.04 to 2.18; Right: P_30%<0.001, P_20%<0.001, ES varying from 1.27 to 1.49, respectively) joint angles of trailing limb in tDCS condition were lower than sham-tDCS condition at 30% and 20% leg’s length obstacle height but excluding 10% leg’s length obstacle height.

The parameters of leading/trailing limb maximum joint angles at tDCS condition and sham-tDCS condition among three obstacle crossing height. “*” indicates significant interaction effects; “†” indicates significant main effects between tDCS and sham-tDCS; “‡” indicates significant height main effects among different leg’s length; “§” indicates significant differences between tDCS and sham-tDCS treatment at each height. (L: Left/R: Right: left and right limb, respectively, as leading limb during obstacle crossing; 30, 20, 10LL: 30%, 20% and 10% leg’s length obstacles height)