Soldier refuses to quit grueling 12-mile march at Fort Dix

FORT DIX, N.J. (WPVI) -- It's a test so grueling that 80% of the soldiers who take it fail - a 12 mile trek that must be completed in 3 hours, all while carrying a 35-pound rucksack and 5-pound weapon.

29-year-old Army Captain Sarah Cudd completed the task on April 27th at Fort Dix in New Jersey even though she says she was "five feet from failure."

The video has now gone viral as Captain Cudd is seen stumbling not once but twice - just yards from the finish line.

That's when her fellow soldiers began to cheer her on.

Captain Cudd completed the Expert Field Medical Badge test in two hours and 47 minutes.

Of the 46 who earned the badge that day, there were 14 women.

She told ABC News that those cheers and the thought of going home to see her husband is what got her up and over the finish line.

Fellow Captain Lloyd Mason posted video of her victory on Facebook and it's going wildly viral.

In the end, Captain Cudd says she felt relief - and gratitude.