Yuebing Li and colleagues developed a lightweight wearable device integrating a variable‐stiffness mechanism with a back‐drivable damping motor to deliver isokinetic resistance training for adolescents with spinal muscular atrophy type Ⅱ. After 6 weeks of training, participants exhibited marked improvements in knee joint mechanics and gained the ability to perform sit‐to‐stand transitions without external support. Notably, these functional gains were largely maintained even after the participants discontinued training and returned to conventional physiotherapy.