I hope the first day treated you well! Mobility and stability are very important parts of the economy of movement. And as we’ve seen time and time again, usually the athlete who moves the best often times moves the fastest. That being said, I hope everyone is addressing any mobility problems they may have.
a) Spend 2 min. foam rolling t-spine (yes, time it so you do it)
b) Double LAX ball t-spine with 25/35# weight on chest
c) 8 min. Tabata Alternating Single Leg L-Sit on ground (Press hands directly into ground next to hips to just lift your body off the ground then alternate holding single leg off the ground with flexed quad and pointed toe)