Safety and Feasibility of Spring-Assisted Sit-to-Stand Training in Individuals with Trunk and Lower Limb Impairments: A Prospective Single-Center Study

Repeated sit-to-stand practice is an important rehabilitation strategy for individuals with trunk and lower limb impairments; however, its implementation is often limited by fall risk, patient fatigue, and the physical burden on assisting staff. This prospective single-center feasibility study evaluated the safety and feasibility of sit-to-stand training using Qolo, a motor-free, gas-spring-assisted sit-to-stand training device, in 40 clinically selected individuals with trunk and lower limb impairments. All sessions were performed under physiatrist supervision. The primary feasibility endpoint was completion of at least three intervention sessions using Qolo. A total of 181 sessions were conducted, and in this clinically selected, supervised cohort, 36 participants achieved the primary endpoint, yielding a feasibility rate of 90.0% (95% confidence interval, 76.9–96.0%). The median number of sessions was 4 per participant, with 48 sit-to-stand repetitions per session and 134 repetitions per participant. Participant-reported fatigue was descriptively higher after training, whereas perceived fatigue among primary assisting staff remained low. No intervention-related adverse events, falls, or skin injuries were observed in this supervised feasibility study. Thirteen device-related problems were recorded, most of which involved the Qolo–tablet connection rather than the assistive mechanism, indicating important usability and reliability issues for further refinement. These findings support the early feasibility of Qolo-assisted sit-to-stand training in this small, clinically selected, supervised, heterogeneous cohort. Further controlled studies are warranted to evaluate clinical effectiveness, sustained adherence, staff workload, device reliability, and safety under routine clinical use.