Łukasz Muszyński, MSc, who cooperates with ONSEN®, is a graduate of the Academy of Physical Education in Poznań, as well as a certified manual therapist of the Kaltenborn-Evjenth method and the McKenzie method - Mechanical Diagnosis and Therapy. He gained his professional experience while working at the Orthopedic and Rehabilitation Clinical Hospital. Wiktor Dega in Poznań, as well as in the Orthopedic Manual Therapy Center for them. Freddy Kaltenborn in Ciechocinek. He has completed many trainings in centers around the world.