A dancer poses for a gym selfie to show off her toned biceps — just hours before her hand was ripped off in a freak boating accident.

Kristie Sita was relaxing with friends on the water when a rope attached to an inflatable wrapped around her wrist and severed her hand when she suddenly jerked backward.

The fitness fan, 21, briefly fell unconscious and woke in the water surrounded by blood.

When she raised her left arm to motion for help, she was horrified to see that her hand was missing.

Sita, of Vancouver, Canada, was airlifted to a hospital where her wound was sealed by wrapping the remains of her palm around the stump.

The severed hand was later found in the water, still entangled in the rope.

But amazingly, Sita says the accident has changed her life for the better and she has gone on to land top dancing roles and amassed 100,000 social media followers.

“I kept thinking it was a nightmare. It couldn’t be real,” she said, reliving the ordeal.

“In five seconds my life had changed forever.”

Sita graduated from high school in June 2014, and five days later she celebrated by going tubing with friends in Ruby Lake on the Sunshine Coast in British Columbia, Canada.

Tubing is an activity where thrill-seekers skid across water on an inflatable donut called “a tube.”

“Ever since I was a young girl, dance was the only thing I wanted to do,” Sita said.

“I graduated from high school a year early so I could move to Vancouver from my home town of Sechelt and pursue dance professionally.

“In the morning, my friends and I headed to the lake to go tubing for the day.”

But beforehand Sita went for a workout, as she did every day, seven days a week, to keep her body in tip-top condition for her dancing.

She took a picture of herself in the gym bathroom mirror, flexing the sculpted bicep of her left arm.

It would be the last photograph of her left hand.

“Around noon, we were heading to meet another boat,” she said.

“The tube was resting on the back because it was too big to fit. It fell out.

“My initial reaction was to reach out to grab the rope. The next thing I remember, I was in the water surrounded by blood.

“I raised my left hand to say, ‘come get me’, and I didn’t have a left hand. At that point, I went into survival mode. I was treading water.

“My friends pulled me back into the boat.”

Sita was taken to the nearest helicopter launch in an ambulance and she was then flown to British Columbia’s Children’s Hospital in Vancouver.

She was rushed into surgery where she only had two questions.

“I looked at every surgeon and I asked: ‘Am I going to die?’

“They said I wasn’t.

“I then asked: ‘Am I going to dance?’

“They said: ‘Yes’.”

Even as she was put under, Sita knew that she was going to be alright.

“I knew that God had a plan for me and that everything would be fine,” she said.

Emergency workers had returned to the lake and had found Sita’s hand, still tangled in the rope.

“They went back to the tube and found my hand, still attached to the rope,” she said.

“They put it in a cooler and it came with me to the hospital. But they didn’t reattach it.

“They were worried it would be paralyzed or there could have been complications and I would have to get it re-amputated.

“Knowing that I was a dancer and an athlete, doctors decided to leave me as an amputee as they knew they could save so much more of my arm doing that. My arm was sewn together by wrapping my palm around the wound.

“My ligaments and muscles were torn around my shoulder. They moved some of my muscles down so that my arm could be fully weight-bearing.”

Sita’s dad, Danny, 57, a restaurant owner, her mom, Angie, 55, a real estate agent, and her sister Rosie, 23, a shop manager, were horrified to see her without her hand.

“It was my family’s worst nightmare,” she said.

“I could see in their eyes that they were worried about my future.

“I did have the feeling that I was going to be OK, I was going to get through it.”

Just two and a half months after her four-hour operation, Sita was training in the gym again.

“I had two months straight of meeting my surgeon, seeing counsellors, intense physical therapy and pain medication.

“After the first month I went to the gym for the first time with a massive bandage. I pedaled on the bicycle because it was the only thing that I could do.

“I needed to sweat again.”

Sita said she was back to “full-on training” after two and a half months.

Today, she shares fitness tips on Instagram and YouTube with her almost 100,000 combined followers.

Her professional dancing credits include roles in Disney’s “Descendants” and the web series “Sacred Lies.”

Astonishingly, Sita insists that if she had the choice, she would still reach for the rope that day on the lake.

“If I had the chance again, I’d still reach back for the rope. Being an amputee has brought so much love and purpose into my life.

“It’s made me notice the people who stuck with me through the hard moments.”

She said it has also changed her dancing style.

“When you love something so much and it’s almost taken away from you, it triggers a new passion that makes you work and fight hard. When you go through something like that, you know you don’t have endless time.

“When I look at my arm, missing a hand, I see strength and courage.

“Just because I don’t have a hand doesn’t mean I’m unable to do anything I want to do.”