She says the hilly course was a good chance to have a hit out after her track season.
Gardner is now looking ahead and hoping to crack her personal best time for a half marathon this season, at either Christchurch in June or Taupō in August.
Gardner's best time for the distance is 1hr, 19m, 34s, which she achieved at Taupō last year.
The race at Whakatane, as well as this Sunday's 10km event at the Tauranga Half Marathon, will provide the build up she needs to set a new personal benchmark.
"I have not done a half marathon since October. It was useful to remember the hurt from the longer distance and pushing that speed for a while. For the first 10km it was alright, but the second half was harder, I had pretty sore quads for a couple of days.
"Christchurch and Taupō are the two events I am focusing on to break my personal best.
"They are mostly flat courses, but the weather in June in Christchurch can be a factor."
Gardner says she found she achieved better results when she stepped up from 10km to half marathon racing.
"Track is harder on the legs, and with the half distance you need to do more endurance. It is a mix of speed and endurance. You do longer, slower trainings and two runs a week longer than an hour.
"I first ran a half on the Gold Coast last year, I did my 10km race and was angry with not getting personal best, so I decided to do the half marathon. I hadn't done any half training and I hit the wall around 11-12 minutes."