The Camperdown-raised, Geelong-based teenager has shaken glandular fever and is now preparing for the 2019 Australian triathlon championships.

McDonald, 19, said the illness gave him a greater appreciation for training.

“You never know what to expect coming off the back of an illness like that which doesn’t really have a timeline to it,” he said.

“It was a big eye-opener into how much I did enjoy the sport.

“It is a massive part of my life and I missed out.

“But it gave me time to focus on other things.

“I recently started a little clothing brand (Kam Industries) which has kept me busy.

“I have really enjoyed doing that as well. It’s a nice little hobby.”

McDonald, who is studying sports science and business management at Deakin University in Geelong, is now training fully.

He spends 20 hours a week – two sessions a day six times a week and one session on the other day – preparing.

It’s paid off with a win in the national duathlon championhips in Melbourne on Sunday where he claimed the men’s 15-19 year old section.

He finished the 5km run, 20km ride and 3km run course in 57 minutes.

“Coming out of the Victorian winter it was a bit of a shock to the system but I handled it quite well,” McDonald said of the warm conditions in Richmond.

“I think I was about five minutes clear (of second place) in the end, I had quite cosy lead which was nice.”

The national triathlon titles in Devonport are now his main focus.

“I had glandular fever going back about 18 months and then I ended up with some post-fever fatigue,” McDonald said.

“I had to take some time off and actually missed most of last season. I’ve just been rebuilding.

“I’ve been back training now for four or five months. I started off really, really slow and I progressed quite quickly.

“I am very pleased with how it’s going. I am looking forward to the Australian championships in March. It will be my first time in the under 23s, so I am not sure what to expect. We’ll slowly build up. My first triathlon for the season will be on November 25 in Melbourne.

“It will be a local series and then there will be a few more of those series between then and March.”

McDonald will tackle the Olympic distance course in Tasmania. The former Camperdown College student is excited to challenge himself over the 1500m swim, 40km ride and 10km run course and will work his his coach, dad Dieter, to ensure he is at his peak for the gruelling competition.