Sacroiliac Joint Dysfunction Consequences and Its Reversal by Manipulation

Sacroiliac joint dysfunction (ASI) is an alteration in the normal biomechanics of the joint, which leads to hypomobility or hypermobility of that joint. It is one of the most common causes of misdiagnosis in low back pain and when not treated correctly, it often evolves into chronic pain (30% to 42%) and disability. Manipulating the dysfunctional ASI appears to result in benefits and significantly positive changes at various levels, in all segments of the human body. With this investigation, the investigators intend to clarify and deepen the possible correlation between the changes that normally accompany this dysfunction, as well as its possible reversibility with its normalization.- Objectives * The investigators will essentially have two main objectives: 1. Mapping of the most evident symptomatic changes, when sacroiliac joint dysfunction is present, in terms of pain, balance and gait ; 2. To try to understand the immediate, global and short-term effect of ASI manipulation, studying the cumulative effect of six sessions and the possible interrelationship between the changes recorded. \- Study design Quantitative, with experimental study design, RCT, with the sample comprising individuals with SIJ dysfunction, where all participants in study 2 will be randomly allocated to the experimental, control and placebo groups. It will be carried out at the University of Aveiro facilities. Initially, the investigators will map the changes present at a physical level, followed by manipulation, evaluating the immediate effect, measuring the degree of pain, unipodal balance and satisfaction with the treatment. The investigators will then evaluate the effect of 3 sessions, on a weekly basis, for 3 weeks. \- Material and methods The investigators will make use of: * Standing flexion test, to define the laterality of the dysfunction; * VAS , to subjectively assess pain; * Pressure algometer, to objectively assess pain ; * Force Platform, to ass