In the cool economics of biology, Jonty Roil knows only too well his genetics are a given but in the geography of life it will come down to a game of probabilities, not certainties.
Roil, like younger sister Hannah and older brother Charlie, is mindful the contours of his genetic map may not necessarily replicate exactly those of his parents but how he interacts with his habitat can, ultimately, influence his development.
One thing he is certain about, though, is what fuels his passion for track and field events in athletics.
"Dad," is the unequivocal response from the 13-year-old of Damian Roil when you ask him where that drive comes from.
"He was a sprinter back in the day, when he got two medals in the 100 and 200 at the North Island Colgate [Games]."
Damian, a builder, got his accolades as a member of the Hastings Athletics Club when he also competed in long jump as a youngster.
The high-twitch fibres seem to be recessive in all three children but as they pile into the family four-wheel-drive vehicle from their Havelock North home it's hard to conceal the excitement and sense of anticipation etched in the faces of Roil and Hannah before they compete in a segment of the country's largest junior athletics starting at Jubilee Park in Inglewood, Taranaki, from today.With another three-day leg scheduled for the Ngā Puna Wai Sports Hub in Christchurch from January 17-19, more than 2100 youngsters will have competed across North and South Island.
Seventy-one athletes from Hawke's Bay are in the mix for the North Island event. The Hastings club has a contingent of 36 with Napier Athletic Club sending 19, Wairoa 14 and Central Hawke's Bay two to the North Island one that has enticed 1155 competitors.
The Roils will ensure they'll keep the family footprint vivid for another generation. Jonty, for instance, will engage in a blend of track (400m, 800m) and field (discus, shot put) events.
The Year 10 pupil from Lindisfarne College has a PB of 59s and 2m19s in his races, respectively, and 40.55m and 10.47m, accordingly, in the throws.
"I started athletics when I was about 2 or 3 so when you're young it's just a little bit of everything but once you start getting older you start specialising," he says, satisfied with his discus accomplishments and gravitating towards 400m on the track.
Jonty, whose intermediate grade discus throw of 30.24m two years ago eclipsed the 30.04m record at Lindisfarne College, is pretty games savvy. It'll be his seventh North Island one. He was third in the North Island 12-year-old boys discus in Hamilton and second in the South Island in Dunedin, both last year.
The former Te Mata Primary School pupil is indebted to coach Sheree Jones for honing his field event prowess but doesn't have a mentor in running.
The challenges of mastering the art of the one and a-half rotations in the ring with proper footwork to eventually hurl the discus into orbit from his index finger fuels Jonty's desire to incrementally make inroads into a discipline that isn't perceived to be as sexy as pole vaulting, never mind the 100m sprint.
"When you really get it going it feels nice," he says, the faint smile that makes it abundantly clear you have to be in it to savour it.
In fact, Roil Jonty qualified for the discus at the New Zealand Secondary Schools' Championship last year but had decided not to go because it meant he was going to have to go from hurling a 1kg apparatus to a 1.25kg one with the bigger boys although he has set his sights on it in December in Tauranga this year.
Hannah does everything Jonty does as well as embracing her father's long jump.
However, it'll be the maiden year in the competitive arena for the 10-year-old who simply wants to make the finals although she isn't going to lose sleep over it if she doesn't.
"It's very exciting," says the Te Mata School Year 6 pupil who wants to see how she goes in the footsteps of her brothers.
Hannah's favourite disciplines are the 400m and shot put.
"I've got good technique [in shot put]," says the youngster who also enjoys the endurance aspect she believes comes from her mother, Sarah, a schoolgirl standard cross-country runner in her heyday.
Like her brothers, Hannah got into athletics from the time she became mobile.
For the record, Charlie, 15, won the silver medal in the 400m junior boys' race at the NZSSC in Wellington last month.
The Year 12-bound Lindisfarne College pupil had finished fifth in the 800m event but also takes part in field events for enjoyment.