But a few weeks later, when the pain returned to his legs and his back and he found it difficult to stand, he was sent for an immediate blood test.
Freddie was in an assembly at Sawyers Bay School when the results came through, showing he had Pre-B acute lymphoblastic leukaemia.
Fortunately, it is the most common and most easily treated form of leukaemia, and for the past year he has been receiving treatment.
He has had several blood transfusions, more rounds of chemotherapy than he can remember and he has lost his hair twice — and the treatment will continue for another year yet.
Today is his eighth birthday, and yesterday he had an early birthday present when he got to watch his sister Olivia, one of his best friends, Hunter Swete, and his principal Gareth Swete have their heads shaved during a school assembly.
It was also a chance to raise funds for the Child Cancer Foundation, and many of his fellow pupils wore coloured wigs to school to celebrate the organisation.
Olivia loves her hair dearly, but was keen to have it shaved off to show her love and support for her little brother and the organisation that has helped him.
But boys being boys, when Freddie was asked how he felt about the act of compassion, he responded: "It’s a nice thing to do — she looks really weird without hair".
Mr Swete said the event was a fun way to support a very serious cause.
"More than three children are diagnosed with cancer each week in Aotearoa, and having seen the impact first-hand, we wanted to help support the Child Cancer Foundation.
"We see an event like this as a small gesture and a responsibility to those who we want to support in their time of need."
After nearly a year off school, Freddie is now in the "maintenance" stage of his treatment and has returned to school.
