"Extra rigidity" means having more stiffness or inflexibility than usual.
Sentences with «extra rigidity»
The intricate roll cage is there for safety as much as for extra rigidity. (speedhunters.com)
The quality of the steering system has been carefully engineered to suppress unwanted vibration while adding extra rigidity to the steering column to communicate a sense of security and responsiveness. (theintelligentdriver.com)
There are metal plates inserted into the back cover to lend the tablet extra rigidity and strength. (theverge.com)