The rules of racing regards foot stretchers and shoes has changed, as of 1 April 2019, and reads as follows:
In all boats the foot stretchers, shoes or other devices holding the feet of the rowers shall be a type which allows the rowers to get clear of the boat with no delay in an emergency. Where shoes or other devices holding the feet will remain in the boat, each shoe or device shall be independently restrained such that when the heel reaches the horizontal position the foot will be released from the shoe. In addition, where laces, Velcro or similar materials must be opened before the rower can remove their feet from the shoes or other device, all such materials must be able to be released immediately by the rower with a single quick hand action of pulling on one easily accessible strap. Note the additional requirement of the strap to undo the Velcro fastenings. The picture below shoes with heel restraints and release strap.
Where shoes or other devices holding the feet will not remain in the boat, each shoe or device must be able to be released by the rower without using their hands or with a single quick hand action of pulling on one easily accessible strap or release device.
This part of the rule refers to the Shimano and similar rowing shoe system.
Antony Reynolds Rowing Safety Adviser | Thames Regional Rowing Council