After all, this is a man who saw all of six minutes of action for the Highlanders last year and then spent the rest of the season in the sick chair.
"It was pretty annoying, to be honest. But it has made me realise that you've got to be a bit more professional with your rehab. [You've] got to be more professional with looking after your body," Manu said.
He strained his medial ligament in the opening minutes of the first game of last season against the Crusaders and was not sighted in a Highlanders jersey again.
"I was told six weeks to get back on the field and then two weeks out from that I strained my hamstring. And it just never came right. The more I tried then it would just get worse. It was just so frustrating. But I just pushed it too hard."
Manu eventually got over the hamstring strain but it was a season of injury for the big Canterbury loose forward.
Back in the red and black colours in the ITM Cup he then injured his other knee and also picked up a high ankle sprain.
That led to a limited involvement in Highlanders training before Christmas as he recovered from those injuries.
But he is now back out on to the field, not far from full fitness and looking forward to getting his feet moving and getting some game time.
"It's going to be tough. There are a lot of good loose forwards in the side and I've only just been able to get back on to the training paddock. There are not many spots up for grabs.
"You've got three games in pre-season to make an impression and try and get in that 22 for game day. So I've got to get myself into the very best shape I can and have a good pre-season."
He had wanted to come back to the Highlanders to join up with a new team under new coach Jamie Joseph.
"I had a good experience down here last year. Although the time did not actually work out that well on the field I made a lot of good friends and enjoyed it.
"Jamie has come in and he is pretty direct in what he wants. He has made it pretty plain what he expects from us and the game plan we have to play.
"There are a lot of new blokes getting involved and a lot of fresh faces so there is plenty of potential there."
Though only 22, Manu is into his third season of Super rugby, having first played representative rugby before he played club rugby.
A nephew of former Wallaby Daniel Manu, he is the second-oldest of five children who grew up in Lincoln, near Christchurch.
His older sister Bessie plays netball for the Central Pulse, while his three younger brothers all play rugby.
Manu was flatting with his Canterbury team-mate Telusa Veanui, and was gradually mastering the arts of the kitchen after a tough start last year.
"I worked as a house master at Christchurch Boys' [High School] straight after leaving school and there you just get fed all the time. You don't have to do anything. So it was a bit of a rough introduction last year to flatting."