Inclusion Criteria:  Written informed consent as documented by signature  For SCI patients:  ASIA Impairment scale (AIS) A-D Focal damage at cervical (C4-C7; i.e. damage rostral of the spi-nal segments innervating the examined hand and leg muscles) or thoracic (T4-T12; i.e. damage caudal of the spinal segments innervating the m. abductor digiti minimi, but rostral of the spi-nal segments innervating the m. tibialis anterior) Patients with cervical SCI must reveal bilaterally intact ulnar nerves as demonstrated by normal compound motor action potential (cMAP), nerve conduction velocity (NCV) and F-wave latencies in clinical neurography. Patients with thoracic SCI must reveal bilaterally intact tibial and peroneal nerves as demonstrated by normal cMAP, NCV and F-wave latencies  Exclusion Criteria:  Women who are pregnant or breast feeding Current neurological problems other than SCI and related impairments Current orthopaedic problems affecting upper and lower extremity movements History of alcohol abuse or the intake of psychotropic drugs History of major cardiac condition (e.g., infarction, insufficiency (NYHA II-IV)) History of major pulmonary condition (e.g., chronic obstructive pulmonary disease (GOLD II-IV)) Current major depression or psychosis Fever of unknown origin