1:06 PM PT -- Halton Regional Police informed TMZ Sports that they did investigate the altercation at the Pure Muscle Fitness location on Sunday and charged Van Wyck with two counts of assault.

Bodybuilding star Jeff Nippard was assaulted by another fitness guru while recording a workout sesh at a gym in Canada this week ... and the attack was caught on video!

Nippard -- known for his scientific approach to bodybuilding -- broke his silence on the incident after video surfaced showing Nippard being violently pushed to the ground by Mike Van Wyck at Pure Muscle and Fitness gym in Ontario.

"Mike Van Wyck jabbed me in the throat twice in the middle of the gym and then shoved my cameraman," Nippard said Monday on social media.

"There is already a lie going around that Mike asked me to stay away from him, and that I didn’t listen, and approached him first. This is FALSE."

Nippard went on to explain ...  saying Van Wyck seemingly had a problem with JN filming for his popular YouTube channel.

"Then he walked back toward me, he said 'turn the camera off' and immediately jabbed me in the throat and I fell onto the floor," Nippard said.

"I stood back up and he told me to never talk about him ever again. Then he jabbed me in the throat a second time."

Jeff also says Van Wyck assaulted his cameraman before walking away.

Nippard said he's unsure why Van Wyck reacted the way he did ... but suspects it stems from a video he made reacting to MVW labeling science-based fitness influencers as "mediocre."

"My opinion is that it was the result of anger brought on by the clip I posted yesterday responding to his question about science-based training," Nippard said, "Pretty wild stuff."

The 34-year-old says he went to the hospital for a CT scan after the attack ... before telling 2+ million IG followers he was okay.

Fellow bodybuilders have rallied to Nippard's defense ... including Quinton Eriya, who said he'll no longer train with Van Wyck, as he doesn't deal with bullies.

Fitness star and nutrition coach Joel Twinem also weighed in, saying the incident wasn't staged.

We reached out to Nippard, Van Wyck, and the gym. So far, no word back.