Mainichi Shimbun further specified that the injuries happened to people “in their 30s to 50s,” and any neck or back injury would require between one to three months for a full recovery.
Naoya Miyasato, architecture professor at Nihon University, believes the issue could lie with the roller coaster’s literal breakneck acceleration, which is comparable to what astronauts experience during a rocket launch. “If a rider can’t withstand the acceleration, then they sustain injury, which could be what’s happening here,” Miyasato said, per Vice.
Despite launching two decades ago, injuries on Do-Dodonpa are a recent occurrence. Even after slightly increasing the ride’s top speed in 2017, no serious injuries were reported until December.
Since no technical issues were reported in the park’s initial investigation, Miyasato suspects the injuries could be linked to how the riders are sitting. “But if a person was sitting incorrectly, say with space between their backs and their seat, it’s the responsibility of the park employees to check their seating position,” he wondered.
source: complex.com BYJOSE MARTINEZ