Sub-study of the Essen Study Centre for the ENTAiER Trial

Inclusion Criteria: * At least 65 years. * Chronic disease (musculoskeletal, neurological, internal medicine). * Increased risk of falling (Berg Balance Scale Score 49 or less). * Medical history: feeling of balance disturbance in the past. * Independent living at home or in an old people's or retirement home. * Regular participation in a one-hour event is possible. * Sufficiently mobile to leave the place of residence independently at least twice a week * Written declaration of consent. Exclusion Criteria: * Disease that restricts participation (e.g. terminal disease, heart failure NYHA III-IV, unstable angina pectoris, uncontrolled seizure disorder, decompensated lung disease that already leads to shortness of breath during light activity, advanced cancer, chemo- or radiotherapy ongoing or during the last 3 months, amputation of one or both legs) * Complete dependence on the rollator. * Visual, hearing or speech problems that limit the understanding of the study documents and processes. * Major cognitive impairment (MoCA score 18 or less). * High risk of needing individual supervision during group sessions. * Severe personality disorder or psychiatric illness, alcoholism or other substance dependence affecting the group sessions. * Life expectancy under 1 year. * Permanent bed-riddenness expected in less than one year. * Regular participation in Tai Chi or EYT in the last 6 months. * Participation in intensive sports activities in the last month (e.g. training in the fitness centre or in sports groups which lead to breathlessness and sweating; skiing, mountaineering in high mountains). * Patients who cannot understand the nature, meaning and necessities of participating in a study. * Participation in another clinical trial within 3 months prior to screening for the ENTAiER trial or concurrent participation in another trial that may interfere with this trial.