The Effects of Eccentric Compared to Standard Strength Training in Primary Spinal Cord Injury Rehabilitation

The goal of this clinical trial is to assess the effects of eccentric arm-crank (KREHA) training compared to standard clinical routine strength (STAN) training in individuals undergoing primary spinal cord injury (SCI) rehabilitation. The main questions this trail aims to answer are: * what are the effects of the training on upper body strength, aerobic performance, muscle volume, functional independence, and health-related quality of life? * is the KREHA training feasible to implement into the rehabilitation routine? Participants will: * perform either 20 KREHA sessions or 20 STAN sessions within 12 weeks * perform a test battery to collect data on training effects before (pretest) and after (posttest) the study intervention

Inclusion Criteria: * 18 years or older. * informed consent as confirmed per signature. * traumatic or disease-related SCI. * participating in the routine strength training program during primary SCI rehabilitation at the study center (generally this is initiated around one month after SCI onset). * wheelchair dependency during activities of daily living, defined by a score of 0-2 in the SCIM subsection regarding "Mobility in the house". * passed sports medical assessment and having sufficient biceps/triceps function to perform arm-crank training, as determined by an experienced sports medicine physician Exclusion Criteria: * inflammatory or neurodegenerative diseases (including multiple sclerosis or Guillain-Barré syndrome). * comorbidities or other health issues that may interfere with study participation, inability or contraindications to undergo the investigated intervention. * MRI contraindications (magnetic metal parts or electronic implants such as pacemakers in the body). * pregnancy (anamnestic).