Hysteresis of the mammalian pCa/tension relation is small and muscle specific.

Small but statistically significant shifts (hysteresis) between the up (increasing tension direction) and down (decreasing tension) pCa/tension relation for several muscle types of the rabbit and rat were found. The largest shift is, at most, 0.093 p units or 60% of that reported for the barnacle muscle. The direction of shift for psoas is opposite to that for the soleus and tibialis.