Five RCTs were included (276 participants, range 18 to 104). On the Newcastle-Ottawa scale one trial scored 5, one scored 7, one scored 8 and two scored 9. Follow-up periods ranged from 30 minutes to seven days.
Two trials found no significant differences compared with baseline following treatment with high velocity, low amplitude thrust manipulation for blood pressure, pulse rate and plasma constituents. Three trials reported significant immediate reductions in self-reported pain. All effects were short-lived with a return to baseline levels, or a reduced effect, being seen at later follow-up points.