German outpatients ( aged 46.710.4 ) with chronic low back pain [ mean visual analogue scale ( VAS ) , 53.912.5 mm ] were enrolled and randomly allocated in a 1:1 ratio to receive either qigong ( 64 patients , 12 sessions with 190min/week over 3 months ) or exercise therapy ( 63 patients , 12 sessions 160min/week ) .