As the subject has expanded from an insurance issue to the wider one of what is suitable for young runners to do I am back in. Gebresselasie ran 2.42 for a marathon at age 16 although I suspect this is pretty modest in the context of East African teenage athletes.

Mary Etta Boitano ran a Marathon in the USA in the early nineteen-seventies in three hours and one minute at age ten. Last time I looked her up on Google she was still running and had children who ran.

Without looking it up I suspect I would find that cross channel swimming has frequently been achieved by young boys and girls.