The right choice, at the right time, of these techniques, these examinations as well as their methods of execution rest on theoretical justifications and a clinical reasoning forming a logical and coherent whole called concept.

Sohier's concept starts from the fundamental idea according to which one can only really heal a joint if one has the potential to bring damaged or diseased tissues back to biological balance; otherwise we add adjuvant, we limit the effects of compensations, we try to reduce the pain, but we do not tackle the primary problem that disrupted the physiology of the articular and periarticular tissues.

The mechanisms determining the biological balance, that is to say the mechanisms which govern cell degradation and reconstruction, are written into the genes and influenced by the relationship that the cell has with its environment (1).

At the level of articular and periarticular tissues, the influencing environment is, to a large extent, physical, mechanical (2). This is the fundamental justification for our intervention, because a biomechanical disorder (pathomechanical state) is sufficient on its own to trigger joint disease.

Analytical Physiotherapy, as conceived by R. SOHIER (2), aims to normalize the physical environment of tissues in order to optimize their biological potential.

From this perspective, the recovery of normal joint kinematics turns out to be the first priority. It has, in fact, for consequences:

- to balance the capsulo-ligamentous tensions and therefore, the mechano-reception,

- reduce excess musculotendinous tension by stretching,

- to lift the contractures of the stabilizing muscles. This, probably by normalization of the periarticular proprioceptive afferents (3). These constants of muscle and tendon traction are, in large part, responsible for muscular dystrophy and tendon degeneration,

- reduce nociception, as a consequence

- reduce vasomotor imbalances

- to improve the functional performance (we showed in 1987 (4), that the recovery of a correct dynamic centering of the humeral head improved the performances, in terms of immediate output in force),

- to find the initial programs of the motor automatisms, disturbed in particular by analgesic behaviors (see the disorders of the posture or the dynamic control of the scapula during the elevation of the arm in the event of injury, even slight of the rotator cuff) .

Apart from trauma, repeated micro-trauma (sports), postural disorders and capsulo-ligamentous retractions, it is the functional predominance which is responsible for these kinematic disorders, also called off-center.

In his numerous publications, Sohier describes the main offsets of the peripheral joints, the spine and the pelvis (5,6,7,8,9,10,11,12,13,14,15).

These decentrings, dynamic at the start, end up being objectified, at rest by medical imaging (examples: superior decentering of the humeral head - fig. 1 - and internal decentering of the femoral head - fig. 2-). It is then often, therapeutically speaking, quite late, because the pathology is structured. Fortunately, our selective and significant clinical examinations make it possible to highlight them from the functional stage of the disease.