The girls, who are aged 11 and 9, have set themselves the challenge as part of the THS 140th anniversary campaign.
The sponsored challenge will see the Lavender and Poppy run 75km each by doing laps around their back garden and heading out on their one daily exercise excursion.
They are using every opportunity before and after school to clock up the miles – they’re even doing laps in between their lessons.
You can donate to the girls’ fundraising causes by clicking here for Poppy and here for Lavender.
