Megan Boxall, 33, from Thorpeness, on running 200 marathons in 204 days for Samaritans.
Residents want to move rocks, that have failed to prevent erosion, further along their beach.
An engineering report finds the longer the rocks are there, the worse the erosion could become.
Megan Boxall becomes the fastest woman to run Britain's coastline.
The defences are the latest ones to be privately funded by residents of the purpose-built coastal village.
Bags of rocks are dropped onto the beach at Thorpeness to try to save properties at risk.
Max Morgan, who is from just outside Ipswich, is the writer and director of Breakwater.
The coastal village has been battered by winter storms causing the demolition of several homes.
Sophie Marple is told sea defences she led the calls for will not cover her home or her neighbour's.
