Startling footage has been released online that revealed the tragic moment a fitness fanatic was killed while doing what she loved best.

According to reports from local media outlets, the footage was shocking and horrifying, to say the least.

The incident arose in Indonesia where a woman was running alongside many other fitness freaks on the treadmill.

But things soon took a turn for the worse when she suddenly took a stumble in the backward direction.

The young woman was identified with the initials FN and was said to be just 22 years old. She can be seen making attempts to grab a window frame but then suddenly disappearing out of sight completely.

As per reports from local media outlets, she had been working out at the gym with her partner and her younger brother.

While her lover requested her to work by his side on the second floor, she was adamant to make use of the treadmill and run alone on the third floor.

She was running for 30 minutes before she went toward a slow walk and took a fall backward as per reports.

She was rushed to a nearby medical clinic with injuries to her head but first responders were unable to save her life in the end as per the latest reports.