What do we know already?
Osteoporosis is the most common bone disease in the world, and causes about 200,000 broken bones every year in the UK. It's more common in older people, especially women, and causes bones to become thinner and weaker. Broken bones in the spine, hip, or wrist are particularly common for people with osteoporosis.
Many martial arts include techniques for breaking a fall, in order to avoid injuries while being tripped or thrown. For example, judo and aikido players learn how to change a fall into a rolling movement, and spread the impact over a larger area of the body. If people with osteoporosis could learn similar techniques, they might be less likely to break a bone during a fall.
Researchers wanted to find out whether it would be safe to teach people with osteoporosis how to fall, or whether the training itself would be too dangerous for people with weak bones. They asked six healthy young adults to go through the training, and measured the stresses acting on their bodies using 3D cameras and a pressure-sensitive plate placed under a judo mat.