A cоmpаrisоn оf the effects of exercise in wаter, exercise on lаnd, or combined (water and land); on the rehabilitation outcome of patients with intra-articular anterior cruciate ligament reconstructions revealed that less joint effusion was noted after 8 weeks in the water group only. The three intervention groups were compared to a control group for the outcome of joint effusion measured as a continuous variable. What is the appropriate statistical test to compare the girth measurement -as continuous scale- among the groups?