Increased toe flexor strength does not relate to altered postural sway during static upright standing after 12 weeks of multicomponent exercise training

Abstract

ABSTRACT This study investigated whether an increase in toe flexor strength influenced postural control during static upright standing after 12 weeks of multicomponent exercise training in healthy young men. Twelve men (18–23 yrs) performed multicomponent exercise 3 days per week for 12 weeks. Twelve additional age-matched men were recruited for the untrained control group. The multicomponent exercise training consisted of strengthening and balance exercises for the foot and leg muscles. Toe flexor strength, foot arch height and postural control were assessed before, during, and after exercise training. Postural control was evaluated using the path of the centre of pressure, which was obtained with a force plate under three standing conditions: double-leg standing with eyes open, double-leg standing with eyes closed, and single-leg standing with eyes open. The dominant leg was used for single-leg standing. After exercise training, toe flexor strength increased by approximately 32% (p < 0.01), whereas the foot arch height did not change. The centre of pressure variables during double-leg standing did not change after exercise training; however, these variables decreased during single-leg standing. None of the variables in the control group changed after exercise training. The relative increase in toe flexor strength was not correlated with the relative improvement in the centre of pressure variables during single-leg standing after 12 weeks of exercise training (total length, r = 0.1734; mean velocity, r = 0.1734; sway area, r = −0.1372). These findings suggest that increased toe flexor strength has no significant effect on static postural control ability after exercise training in young men. Highlights Twelve weeks of multicomponent exercise training aimed at strengthening foot and leg muscles increased toe flexor strength. Multicomponent exercise training did not alter postural stability during double-leg standing, but improved postural stability during single-leg standing. Increased toe flexor strength did not relate to altered postural stability during static upright standings after 12 weeks of exercise training.