|2018 European Championships|
|Venues: Glasgow, Edinburgh and Berlin Dates: 2-12 August|
|Coverage: Live across BBC TV, BBC Radio 5 live and sports extra plus the BBC Sport website with further coverage on BBC iPlayer, Red Button, Connected TVs and mobile app.|
Overcoming illness, mental barriers and physical tests are commonplace in everyday life.
For a professional athlete, such challenges can be a matter of major importance - fail to bounce back and your career could be in jeopardy.
But the ability to overcome any obstacle is often what separates the athletes from the champions.
Here are the stories of four extremely tough women heading to the European Championships in Glasgow and Berlin, each of whom has had to overcome their own challenges to just get to the start line.
Jazz Carlin (open-water swimming)
Olympic silver medallist Jazz Carlin has not had the easiest few months.
Having suffered with an illness before the Commonwealth Games in April, she finished only sixth in the 800m freestyle before withdrawing from the 400m.
When she returned from down under, Carlin threw herself back into training, turning her focus to the open water, but that was not straightforward either.
The event means competitors spending up to two hours in rough seas or chilly lakes, fighting for a slipstream (often coming into contact with a stray, sharp elbow), rivals grabbing your arms and legs, and - according to Carlin - "a few dirty tactics". It is not a sport for the faint-hearted.
"People think I'm a bit mad switching from the calm of the pool," says the 27-year-old. "It is tough - I finish a race and I am absolutely wiped out."
Not only has she had to battle the ocean (and a fear of jellyfish) she has also had to overcome a bout of pneumonia.
"I thought I just had the flu!" she says. "But the doctors sent me to hospital because my heart rate was 130 when I was sat down - for an athlete it's normally around 40 or 50 so it was a bit of a shock."
After a three-month recovery process, Carlin is nearly back to full fitness and it is clear she is revelling in it.
"I am now loving training and chasing the boys down," she says. "I am glad I can say I am going to be in Glasgow and giving it absolutely everything.
"When you have had to overcome a bit of a rollercoaster to get there, you appreciate it a lot more."
Laura Kenny (track cycling)
Cast your mind back to 2012, when 20-year-old cyclist Laura Trott became one of Team GB's brightest young stars having left London with two Olympic gold medals (and few grown-up responsibilities).
Fast forward six years and Trott (now Mrs Kenny, having married fellow cyclist Jason Kenny) has four Olympic gold medals, two dogs and an almost one-year-old son. A lot can change in six years.
"Albie is walking and everything now. I am like 'please just stay my baby forever!'" Kenny tells BBC Sport.
Any athlete-mum will tell you coming back from childbirth is one of the toughest challenges they face.
"I have slowly got back into cycling this year. After having Albie, my body had completely changed. I couldn't train as hard in the gym as I wanted to."
Kenny, 26, says her motivation to get back to her best has unexpectedly changed since becoming a mother.
"When I get on my bike and I'm finding it hard, I just think 'how proud Albie would be if you can just get through this' so it does put a completely different spin on it."
Kenny is not taking it easy in Glasgow - she will be competing in the elimination race, the team pursuit, and the madison with Katie Archibald.
Jazmin Sawyers (long jump)
Mental toughness is something all athletes need, so what happens when you start to doubt yourself? Just ask long jumper Jazmin Sawyers.
The 24-year-old was left questioning whether her best days as an athlete were behind her after a poor performance at the British Indoor Championships.
"I knew I should not be turning up and jumping 6.08m at a competition," Sawyers, whose personal best at the time was 6.75m, told BBC Sport.
"You do start to doubt yourself and think, 'maybe I am not as good as I think I am'. People said: 'You are 5ft 3in. You are never going to be a proper long jumper.' You start thinking, 'maybe it's true'."
But relocating to Florida, linking up with a new coach - Lance Brauman (the man behind new sprint sensation Noah Lyles), and a change of mentality gave Sawyers the boost she needed.
Training with Olympic and world champions, Sawyers soon realised that more often than not she would just about be keeping up with the training group, but she is starting to make enough improvements to close the gap.
"I have just persevered," she says. "I have re-learned how to run and am just doing what my coach tells me. It's that simple."
The result? A big personal best of 6.86m at the British Championships in July.
She says: "I still get that imposter syndrome, that 'should I really be here?' but that voice is getting quieter and quieter."
Siobhan-Marie O'Connor (swimming)
O'Connor overcame a life-changing diagnosis at 17 to win an Olympic silver medal, but her battle with ulcerative colitis is far from over.
"Every athlete has something they have to deal with, be it injury or illness - this is mine," said O'Connor, whose Olympic medal came in the 200m medley at the 2016 Games.
Ulcerative colitis is a chronic bowel condition that can lead to weight loss and exhaustion, and O'Connor says even six years after diagnosis she still feels she has a lot to learn about it.
But she also wants prove it will not stop her achieving her goals.
"I used to not want to talk about it because I didn't want people to think it was an excuse or even a weakness," she added.
"But when I opened up about it, I had so many amazing messages from people saying 'thank you for talking about it because it isn't something you should be ashamed of'."