[P3-0794] The effect of different force direction and resistant level during the resistive static contraction of the lower trunk muscles on the lower soleus H-reflex in side-lying
Keywords:H-reflex, static contraction, remote after effect
【Purpose】
The purpose of this study was to compare neurophysiological effects of descending remote after effect（RAE）of the resistive static contraction of the pelvic depressors（RSCPD）while left side-lying on the lower（left）soleus（SOL）H-reflex compared with the different resistive exercises considering the strength and direction of the resistance.
【Methods】
The ethics committee of a University approved the study protocol. Four different RSCPD in different direction of traction（neutral and diagonal）and strengths（10% of the isometric maximum voluntary contraction（MVC）；weak, 20% of MVC；strong）were performed randomly in twelve normal subjects. Before, during and after the RSCPD, both left H-reflexes and M-waves were measured. For each reflex recorded in this study, repeated H-reflexes and M-waves（1 Hz）were elicited sequentially for a period of 240 s. Condition-C1（three trials；60 s）represented the phase of rest, condition-C2（20 s）the phase of each resistive exercise, conditions-C3（20 s）～-C12（20 s）represented the rest phase after each resistive exercise. For comparison, each of the H-reflex amplitudes were normalized to the corresponding max M-waves（Mmax）, which was expressed as the ratio of H/Mmax（H/Mmax）. Three-way measures ANOVA was used to determine the time-course effects（thirteen conditions：conditions-C1～-C13）, RSCPD effects（four levels；（neutral-weak, neutral-strong, diagonal-weak, and diagonal-strong））and individual effects.
【Results】
A three-way ANOVA for the H/Mmax showed that the technique and individual showed significant effects（technique；F（3,517）=7.54, p=0.00）, individual（F（12,564）=327.954, p=0.000）and time course（F（11,517）=0.23，p=1.00）and interaction（F（33,517）=0.50, p=1.00）showed no effect. Post-hoc comparisons（Bonferroni）indicated that significant depression following the diagonal-strong RSCPD was found when comparing with the diagonal-weak and neutral-weak RSCPD.
【Discussion】
Neurophysiological descending RAE of the RSCPD was movement direction- and load-dependent activity in soleus H-reflex.
The purpose of this study was to compare neurophysiological effects of descending remote after effect（RAE）of the resistive static contraction of the pelvic depressors（RSCPD）while left side-lying on the lower（left）soleus（SOL）H-reflex compared with the different resistive exercises considering the strength and direction of the resistance.
【Methods】
The ethics committee of a University approved the study protocol. Four different RSCPD in different direction of traction（neutral and diagonal）and strengths（10% of the isometric maximum voluntary contraction（MVC）；weak, 20% of MVC；strong）were performed randomly in twelve normal subjects. Before, during and after the RSCPD, both left H-reflexes and M-waves were measured. For each reflex recorded in this study, repeated H-reflexes and M-waves（1 Hz）were elicited sequentially for a period of 240 s. Condition-C1（three trials；60 s）represented the phase of rest, condition-C2（20 s）the phase of each resistive exercise, conditions-C3（20 s）～-C12（20 s）represented the rest phase after each resistive exercise. For comparison, each of the H-reflex amplitudes were normalized to the corresponding max M-waves（Mmax）, which was expressed as the ratio of H/Mmax（H/Mmax）. Three-way measures ANOVA was used to determine the time-course effects（thirteen conditions：conditions-C1～-C13）, RSCPD effects（four levels；（neutral-weak, neutral-strong, diagonal-weak, and diagonal-strong））and individual effects.
【Results】
A three-way ANOVA for the H/Mmax showed that the technique and individual showed significant effects（technique；F（3,517）=7.54, p=0.00）, individual（F（12,564）=327.954, p=0.000）and time course（F（11,517）=0.23，p=1.00）and interaction（F（33,517）=0.50, p=1.00）showed no effect. Post-hoc comparisons（Bonferroni）indicated that significant depression following the diagonal-strong RSCPD was found when comparing with the diagonal-weak and neutral-weak RSCPD.
【Discussion】
Neurophysiological descending RAE of the RSCPD was movement direction- and load-dependent activity in soleus H-reflex.