Supplementary file 1. Summary of the typical course and content of OMT sessions during the study

History and physical examination (5 min.)Thorax (15 min.) Diaphragmatic, costal, sternal and subclavicular areas (myofascial techniques). Paravertebral areas (myofascial, ligamentous, volumetric and rib raising techniques). Endothoracic fascia, pleura and lung (visceral techniques). Assisted breathing movements with pumping (low, mid and upper ribs).Neck (10 min.) Skin and superficial fasciae, with special attention to areas involved by sclerodermic

(fascial and soft tissue techniques). Trapezius, levator scapulae, scalene, sternocleidomastoid and posterior deep muscles

(myofascial and muscle energy techniques). Pleural domes (ligamentous and visceral techniques).Cranial base (5 min.) Occiput/atlas decompression, cranial base expansion and occipitomastoid suture

techniques. Other cranial techniques (compression of the fourth ventricle or venous sinus release

techniques).Upper limbs (20 min. per limb) Upper limbs treated one at a time, from proximal to distal, and with priority given to the

most involved areas. From superficial fasciae (including the skin) to deeper connective tissue (including

interosseous membranes, flexor retinaculum, palmar aponeurosis and joint capsules) and muscles.

Techniques used were fascial, ligamentous, myofascial, soft tissue, decompression, tissue plane dissociation or muscle energy (addressing all forearm, wrist, hand and finger ROM).

For the more fibrotic areas (mainly the fingers), the osteopath wore soft grip gloves in order for the contact with the skin to be stronger than the adhesions of the underlying tissue plane.

Total duration: 75 minutes

Supplementary file 2. Hand photos before the first treatment (upper panels) and after the last treatment (lower panels). The participants were instructed to make a fist and to open the hand as much as they could after a few repetitions.