DESPITE initial concerns over an innocuous blow to the head during the VFL finals that resulted in concussion, Collingwood's James Aish has resumed training with a full bill of health.

Aish says he has recovered completely from three head knocks last season – one in round nine, when he fractured his cheekbone in a collision with Hawthorn's Daniel Howe, a second in July in the VFL, and the third in September.

He admitted this week to being worried after the third blow when he suffered concussion symptoms at half-time in the VFL final despite a seemingly innocuous bump.   

It followed a succession of head knocks throughout Aish's footballing career, with the young South Australian unsure of exactly how many he's had.

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"I got a knock and it wasn't much of a knock at all and I got concussion from that," Aish told AFL.com.au this week.

"When you get the little ones that become an issue, it's not good."

However, the 22-year-old took some time off after the last incident, holidaying on Victoria's Surf Coast and in the US before resuming training.

"I had a bit of time off and it's all good now," he said.

"It's certainly not an issue going forward at this stage for me. I'm not worried about it at all.

"The more it's talked about and the more you read about it, you can think about it a bit more.

"It can become a bit of a worry, but I'm not thinking about it."

Brisbane Lions defender Justin Clarke was forced into retirement aged just 22 in 2016 because of repeated concussions, while head knocks and hamstring issues contributed to the end of Collingwood's Ben Sinclair's career last year.

Clarke retired after a training incident saw him black out for 15 seconds before losing all memory of the moment his forehead hit the knee of a teammate.

Even more alarmingly, he had no memory of the next three weeks.

Aish says he feels back to normal after his series of collisions last year, and intends to continue playing without the helmet he wore after the cheekbone fracture.

The helmet had to be modified to allow him to hear properly, but he said it still limited his peripheral vision.

Aish has enjoyed an uninterrupted pre-season this year and is poised to play in Collingwood's AFLX and JLT Community Series as he attempts to find a permanent position in the 22 this season.