I do lots of Zercher these days, and with Zercher deadlift from the floor being the biggest culprit, I find that my pecs are really sore the day after. How is that? From trying to keep the bar as close as possible?
Thanks 
The pectorals are involved in transverse adduction/flexion of the shoulders… bringing the arms toward the midline of the body (like in a fly or pec deck). When doing a Zercher, especially if you use the “linked arms” grip (holding both hands together) you are using that function to hold on to the bar. It is an isometric action but there is still an intense contraction that might have a training effect.
Ok thank you I guess my upper body wasn’t used to that stimulus!