Execution
1) Measure your basal ROM.
Stand tall against the wall , feet shoulder width or narrower.
Lift one arm like you would do a strict hspu, shoulder width
Make a mark on the wall at your wrist.
Make a mark on the wall marking your height
Measure the distance between wrist and your height. This is your basal ROM.
2) Find XRM in ROM
tempo 40X1, shoulder width. This could be a negative ROM (plates/mats under head) or positive ROM (plates under hands)
XRM ROM = Basal ROM + plate ROM.