MOESM1 of The effect of a single spinal manipulation on cardiovascular autonomic activity and the relationship to pressure pain threshold: a randomized, cross-over, sham-controlled trial PicchiottinoMathieu HonoréMargaux Leboeuf-YdeCharlotte GageyOlivier CottinFrançois HallmanDavid 2020 Additional file 1. Post session questionnaire