Last August, the 19-year-old world champion flew too far on a practice jump in Germany and smashed into the ground, tearing both the anterior cruciate and medial collateral ligaments in her right knee and badly damaging both sides of her meniscus.
"I laid at the bottom of the hill and thought everything was over and that sponsors were going to drop me and that my dreams of becoming an Olympian for this year were over," said Hendrickson, who had been one of the favourites to take gold in the inaugural women's jumping event.
Normally, an injury like that could take a full year to recover from, but when medical experts told her she had a chance of making the Olympics, she did all she could to get there.
The first step was to have her knee reconstructed.
"Once I'd had surgery I was in so much pain I didn't want to put any pressure on (the knee) and I completely pushed the thoughts of Sochi out of my head," she told Reuters.
When the knee had healed enough she started a series of agonising exercises with a physiotherapist that often reduced her to tears. And then, while her team mates were competing, she spend eight hours a day six days a week in the gym.
"I trained my butt off and I'm stronger than ever," she said.
Hendrickson also consulted with psychologists before returning to the hill.
"If you're scared, this is the wrong sport for you. So that's how I had to look at it and push the thoughts of my ACL possibly blowing again on that first jump out of my head and just go with it," she told Reuters.
Asked how fed up she was with questions about her knee, she replied: "It's actually getting old. I just want to be considered healthy now."
Team mate Jessica Jerome says she has never seen anyone work as hard as Hendrickson did to recover.
"Having an injury is about more than hard work. You can work as hard as you want but your body still has to respond and luckily hers did," she told reporters last month.
Hendrickson, who stands 5ft 4in (1.63 metres) and weighs around 95 pounds (43 kilograms), started skiing at the age of two and took an interest in jumping after watching her elder brother on the hills at their home in Park City, Utah.
She started jumping at the age of seven and describes it as "exhilarating, it's fun, it's a million different adjectives all put into a five-second span of flying through the air".
Alan Alborn, coach of the U.S. women's team, first saw her at the age of about 10 and knew right away she was special.
"Her performances are always aggressive, dynamic and fearless and in this particular sport that kind of attitude gets you a long way," he said.
"A lot of Type A personalities like to fly fast and jump far."
Hendrickson showed her class in the inaugural women's World Cup ski jumping season in 2011/12, winning nine of the 13 events to run away with the title.
Her wins attracted support from sponsors like Red Bull, Kellogg's and Nike, making Hendrickson much more prominent than the other members of the U.S. team.
This prompted media accounts suggesting her success was causing tensions with her colleagues, stories that Alborn said had been oversimplified.
"While they are a close team, they are also fierce individual competitors. Of course there will be strains when one individual athlete has rapid success," he told Reuters.
"But it also pushes each athlete to be better and that's a positive for me as their coach."
Hendrickson says the U.S. women jumpers have been traveling together for six years and are like sisters.
"I haven't felt any negativity from them and I hope we can continue to have a good friendship regardless of what the results are on the hill," she said.
In April 2012, Hendrickson had surgery to repair cartilage damage in her left knee, which gave her very little time to train for the 2012/2013 World Cup season. Nevertheless she took second place overall and also won the World Championship in March 2013.
Hendrickson, who estimates she has jumped between 10,000 and 12,000 times in all, has not competed at all this season. Yet the U.S. team was convinced enough about her recovery that it named her as one of the three women jumpers for Sochi.
"We still are very calculated in her training and physical therapy to insure she stays on track," said Alborn.
"Sarah has a very strong will, and like many athletes who have suffered injuries, she will use it to her advantage to be even better and stronger."
Alborn says Hendrickson's competitors are "scared to death" of her. Yet the injury means she has had no time to train and will find it tough beating 17-year-old Sara Takanashi of Japan, who has a huge lead in this year's World Cup standings.
"Sara is jumping at a very, very high level right now ... I would definitely have to show up on my best day in order to even (provide) competition to her," said Hendrickson.
- Sports & Recreation