Fig. 2.

Delta-F (ΔF) distribution before and after eliminating unit pairs with less than 500 ms recruitment time difference. A: before controlling for the recruitment time difference, 10,819 unit pairs were observed from the soleus. After making the 500-ms recruitment time difference cut, 8,443 unit pairs remained for analysis. B: there were 23,121 unit pairs observed from the tibialis anterior (TA) before controlling for the recruitment time difference. After, 17,987 unit pairs remained for analysis. For both muscles, eliminated unit pairs mostly had lower ΔF than remaining unit pairs. The Kolmogorov-Smirnov test verified that the ΔF distributions are not statistically different than normal (P < 0.0001).