All hail oh great and powerful leg day, greatest of all days.
Okay, plank'd 300 seconds, not that hard, not easy, but I could have probably gone longer. Will go for more next week.
I do it at the end of my workout and it's leg day so I felt it in my quads. Core was fine, no shaking. I was trying to adjust my position, had to stop myself from doing that, so that's a sign I was nearing the limit. We'll see. I was shaking the first time, could be mental.