Children who were born unable to control their bodies stood up on their own for the first time. It was thanks to rehabilitation training while wearing a robot on the knees. Robots that helped children walk existed before, but the machines provided force and did not develop muscles like this time.
A research team led by Professor Yanggang Feng in the Department of Mechanical Engineering at Beihang University in China said on the 21st that it developed a wearable robot that promotes neuromuscular recovery in children with spinal muscular atrophy (SMA). According to the team, the rehabilitation effect persisted even after stopping the training with the robot. It showed the possibility of sustained recovery, not just a short-term boost in motor function.
◇ After 6 weeks of rehabilitation training, able to stand up independently
Spinal muscular atrophy is a degenerative neurological disease in which motor neurons are damaged and muscles atrophy. It is a genetic disease caused by a mutation in the SMN1 gene and occurs in about 1 in 10,000 newborns. Over the past 10 years, treatments that administer drugs to activate the problematic gene or modify the gene itself have been developed, stopping or greatly slowing the loss of nerve cells. However, they could not restore muscles that had already atrophied.
The research team developed a wearable robot that helps with isokinetic rehabilitation training. Isokinetic training is a method that extends the knee at a constant angle over a set time. If the patient exerts strong force, the robot attached to the knee increases resistance accordingly to prevent moving too fast. Conversely, if the patient exerts weak force, it lowers resistance to match the angular velocity. This helps the patient continue to maintain strong muscle force independently.
Robot rehabilitation training was conducted with six patients aged 6 to 10 who could not stand up from a seated position without help from others. The children received training to move their legs more than 60 times, five times a week for six weeks. The team turned the rehabilitation training into a game to boost participation. When the children extended their legs, they could see themselves kicking a ball on a monitor. After completing the training, all of the children were able to stand up from a seated position even without the robot.
Video imaging showed that the volume of the quadriceps, the thigh muscles, increased by 19%. Rehabilitation training strengthened their muscles so they could stand up. The children could generate more than twice the force when flexing their knees. The initial angle required to stand up from a seated position decreased from 111 degrees to 104 degrees. In other words, they were able to stand up from a lower posture.
In particular, the rehabilitation effect was sustained over a long period. Later, the children performed low-intensity isokinetic rehabilitation training using the robot three times a week for six weeks and then returned to conventional physical therapy. A 30-day follow-up found that the rehabilitation effect persisted even after stopping the robot training.
Professor Feng said, "Temporarily using a wearable robot suggests that it can promote long-term neuromuscular recovery." Tony Shu, a researcher at the Massachusetts Institute of Technology (MIT) Media Lab and a co-corresponding author of the paper, said, "According to parents, it has become much easier for children at home to roll over and get up from bed or to move their bodies into specific positions."
◇ Unlike previous robots, delivers a fundamental therapeutic effect
Patients with spinal muscular atrophy had also received isokinetic rehabilitation training before. However, such rehabilitation was only possible at medical institutions with specialized equipment. The devices themselves were bulky and difficult for children to use. The research team said the robot mounted on the knees weighs 0.96 kilograms, so it is not burdensome to wear.
There had also been robots for patients with spinal muscular atrophy before. The Spanish National Research Council (CSIC) and its spinoff Marsi Bionics developed the first pediatric exoskeleton robot in 2016. The exoskeleton takes the form of a gait-assist device that wraps around the legs. It fixes the child's body in place with aluminum and titanium materials. It weighs just under 12 kilograms.
When a child tries to walk, sensors in the exoskeleton robot detect muscle signals and drive motors at the joints accordingly. In other words, the robot's legs move as the child intends. Thanks to the robot, a 5-year-old patient with spinal muscular atrophy was able to walk for the first time since birth. However, the exoskeleton robot only assists the act of walking and does not build muscle. It is not a fundamental treatment. By contrast, the knee-mounted robot in this study promoted motor signal transmission and built muscle.
However, this study did not compare with a control group of patients who received rehabilitation training by methods other than the robot, so there are limits to asserting that the robot produced the rehabilitation effect. Families of patients were reluctant to participate if they could not use the robot. The research team said that if investors step up, the wearable robot could be developed as a complementary tool to gene therapy for spinal muscular atrophy. They also expected that the same approach could be applied to training other joints and muscles.
References
Nature(2026), DOI: https://doi.org/10.1038/s41586-026-10642-0
CSIC(2016), https://www.eurekalert.org/news-releases/521825