“…Limiting assessment based on RCTs and meta analyses with level 1 or 2 per se must be seen just as critically as limiting the time frame of analyses for guidelines to the last few years. Especially in the domain of physical medicine and general rehabilitation many proven therapies such as massage, electrical therapy and ultrasound are documented in older studies published in books and are therefore not used in assessments [2, 3,5,8,[10][11][12][13][14][15][16]18,19,21,22,26]. The biological variability of the human being is the reason why, in the field of medicine, results even from high level studies can never describe the effect of an intervention as precisely as in mathematical or physical studies [28].…”