A Zhineng Qigong Intervention for Patients With Chronic Low Back Pain and/or Leg Pain

General inclusion criteria: * Low back pain and/or leg pain (caused by lumbar disorder) with at least 3 months duration. * Pain intensity in lumbar spine and/or leg (caused by lumbar disorder) at least 30 on a 0-100 Visual Analogue Scale (VAS), being "the best description of pain the past 2 weeks". (As enrolment initially went slow, also patients scoring VAS pain intensity 25 to 30 became eligible if their pain situations were qualitatively assessed severe, resulting in enrolment of 5 such patients). * Resident in the county of Skåne (southern part of Sweden). * Comfortable with the Swedish language. * Acceptance not to practise Yoga, Meditation, or any other Qigong exercises during or 1 month after the intervention. Specific inclusion criteria, clinical pathway: * Postoperative after lumbar spine surgery: one lumbar spine surgery 1-6 years earlier, for either spinal stenosis, spondylolisthesis, or segmental pain. Pain intensity (back and/or leg) at least 30 on 0-100 mm VAS in latest SweSpine follow-up protocol. * Patients from Primary Healthcare Centres: chronic low back pain (at least 3 months duration) with or without leg pain. * Patients on waiting list for lumbar spine surgery: Planned first surgery for either spinal stenosis, spondylolisthesis, or segmental pain. Exclusion criteria: * Lumbar spine or other major surgery planned before, during, or within 1 month after the intervention period. * History of serious mental disease, epilepsy, or narcolepsy. * Current abuse of medicament, drug, or alcohol. * Pregnancy (due to practical reasons only).