If you don't know much about athletics, you probably won't have heard of Lloyd Cowan.
But when news of Cowan's death at the age of 58 broke last week, hundreds of athletes paid tribute to the Briton, including sprint superstars Usain Bolt and Shelley-Ann Fraser-Pryce.
Cowan was best known for coaching Christine Ohuruogu to 400m gold at the 2008 Olympics, world titles in 2007 and 2013, and victory at the 2006 Commonwealth Games. Ohuruogu remains the only British woman to win a Olympic gold in a flat, individual sprint event.
In a statement posted on social media, Ohuruogu said "[Cowan's] passion for coaching was limitless. His energy to pass on knowledge could not be contained.
"He coached with his heart and had a humility that ensured he had love and time for others regardless of their standing."
However, before his coaching career, he was an athlete himself, representing England at the 1994 Commonwealths. His club was Woodford Green and Essex Ladies and he ran the 110m and 400m hurdles. Cowan won three bronze medals at the AAA Championships - the precursor to the British Athletics Championships - in the sprint hurdles during the 1990s, an era dominated by former world record holder Colin Jackson.
He was 32 years old, working for Southwark Council and already coaching young athletes when he was selected to represent England.
But the joy Cowan brought to tracks and athletes around the UK was arguably the biggest impact he had on his sport.
Two of his athletes, Andy Turner and Bianca Williams, have told BBC Sport why he was one of a kind, and one of the greats.
Pure passion & a global impact
Athletes from around the world have paid tribute to Cowan with stories about how instilled confidence, made them laugh and helped them find a love for the sport. Many he didn't even coach.
There were social media posts from legends like Jamaica's Bolt and Fraser-Pryce, who said: "No trip to London would be complete without a conversation with Coach Lloyd. His laugh and smile was everything, especially around the discussion of Jamaican food or jokes. You will be missed."
But what did Cowan mean to those he spent years coaching? The ones he saw every day?
Former 110m hurdles European champion Andy Turner was 21 when he started training with Cowan. He stayed with him for 13 years until his retirement.
"Every training camp, every time you went to a race, everyone there would know Lloyd. He really was one of a kind and such a huge personality," he told BBC Sport.
"I wouldn't like it as an athlete being on the circuit without Lloyd now. There's nobody better to give you a pep talk before a race. He would make you believe you could win."
In 2009, Turner was cut from UK Athletics' funding list.
"The powers that be said: 'You're too old and too slow to make a final,'" said Turner.
"Lloyd knew I still had something in me and I just needed a good, injury-free year. He had that belief in me constantly."
The following year, Turner did become European and Commonwealth champion, he said seeing Cowan's face after winning his title in Barcelona made everything worthwhile.
"He knew what I'd been through and I knew how hard it was for him as a coach," said Turner. "I remember giving him a hug and he was like a kid at Christmas."
Watching world title win from the toilets
When Ohuruogu won her 2013 world title, Cowan didn't watch the race. Instead, he sat in the toilets at the warm-up track.
"He always watched our finals from the warm-up area on the TV screens. When his athletes did well he just marched around the track and clapped and talked to himself. It always brings a smile to my face," Turner said.
"It didn't feel like work; it wasn't a chore. I loved every session. You'd get your training done and afterwards, you'd sit around and have a laugh with him. He was a friend, not just a coach."
As well as being a friend, several athletes have described Cowan as a father figure, including European and Commonwealth medallist Bianca Williams.
"I'll miss everything about Lloyd," Williams, who joined the group aged 16, told BBC Sport.
"He was such a great guy. He was very loud, very vibrant. You would always know when Lloyd was in a room, and you would always smile.
"He would always make sure I had the right footwear, make sure I had food - even if it meant going to chicken shops after training.
"I'm very grateful Lloyd was in my life. He changed my life. He would always tell me how proud he was of me and always believed in me.
"That confidence he had in me helped me achieve my goals."
A father figure to his athletes, Cowan also had his own children.
One of them, Dwayne Cowan also made his international debut as a 32-year-old - and it was his dad who coached him.
Dwayne was chosen to represent Great Britain in the 400m and 4x400m relay at the 2017 World Championships in London, winning relay bronze just two miles from the track where his father coached for so many years.
Like so many during the coronavirus pandemic, Cowan will not have the funeral he deserved, but Turner says it would be "absolutely heaving" without Covid-19 restrictions.
"Lloyd can't just be yesterday's news. His legacy needs to live on forever," he added.
"He wasn't just an amazing person, he was also a hugely successful coach who deserves to be remembered as one of the greats."