In the experimental group, instrument-assisted soft tissue mobilization techniques and post-isometric horizontal adduction stretches were performed. The technique lasted 20 seconds in a parallel direction and 20 seconds in a perpendicular direction on the posterior shoulder and scapula muscles. While the dominant hand was used to hold the instrument, the other hand was used to tighten the skin medially to ensure an even area of treatment.

Control group only underwent soft tissue mobilization. With the subject in the supine position, passively adducting the arm horizontally until the first motion barrier and performing active horizontal abduction for 5 seconds at 25% of force. The arm was then taken to the new motion barrier, repeating this process three times.

instrument-assisted soft tissue mobilization techniques (applied with the subject in prone position. The technique lasted 20 seconds in a parallel direction and 20 seconds in a perpendicular direction on the posterior shoulder and scapula muscles. While the dominant hand was used to hold the instrument, the other hand was used to tighten the skin medially to ensure an even area of treatment) and post-isometric horizontal adduction stretches (carried out with the subject in the supine position, passively adducting the arm horizontally until the first motion barrier and performing active horizontal abduction for 5 seconds at 25% of force. The arm was then taken to the new motion barrier, repeating this process three times).

The patient was placed in the supine position at 90º shoulder abduction, 90º elbow flexion. By stabilizing the scapula at the acromion, the shoulder was taken at a maximum range of internal rotation. The range of motion was measured with a digital inclinometer, model Tacklife MDP01, the angle of the edge of the ulna coinciding with a line perpendicular to the stretcher. For horizontal adduction, the arm was placed in the same initial position in neutral rotation and while stabilizing the lateral edge of the scapula, the arm was adducted to its maximum range of motion. The angle between the line of the ventral edge of the humerus and a line perpendicular to the stretcher was measured with the inclinometer. The range of movement in internal rotation is 0-70º and the range in horizontal adduction is 0-30º (higher degrees, greater mobility in horizontal adduction of the shoulder).

An 11-point numerical rating scale was used to rate subjects' perceptions of discomfort at the posterior aspect of the shoulder. This 11-point scale evaluates the discomfort from least to most, asking each subject to define the level of discomfort in the back of the shoulder in the maximum range of motion of internal rotation and horizontal adduction of the shoulder. This 11-point scale measures the perception of stretching, in a range of 0 to 10 points ("0" on the stretch sensation scale indicated ''no discomfort'' and "10" indicated ''the worst possible discomfort and increased sensitivity')