Figure 6. Changes in spinal excitability during isometric and anisometric contractions.

The mean ± SEM (n = 12) of submaximal (H₈₀) (top panels, A and B) and maximal (H_max and H_max) (bottom panels, C and D) H-reflex normalized to the corresponding maximal M-wave for the soleus (SOL, left panels) and medial gastrocnemius (MG, right panels) during lengthening (hatched bars) isometric (open bars) and shortening (filled bars) contractions. Modulations of these ratios were investigated during passive actions (REST) and during maximal voluntary contraction (MVC). ***Significant difference at P < 0.001: lengthening vs. isometric and shortening.