Mohamed Lahna removes the prosthetic he uses for everyday activity, attaches another to his right leg worn specifically for running, then takes off around the bright blue track at the College of San Mateo among all the lunch-hour walkers and joggers.
Tucked away in the hills with a spectacular view of San Francisco Bay below, Lahna hustles along for several laps before stopping to stretch his left leg on a hurdle. A paratriathlete for five years, the 31-year-old native of Morocco has his sights set on the 2016 Paralympics in Rio de Janeiro - a longtime goal.
Born without a femur in his right leg, Lahna has a tiny foot at about knee level that fits into a prosthetic which goes up to his hip. He has proximal femoral focal deficiency (PFFD), a birth defect that affects the hip and pelvis.
It has hardly slowed him down.
In April, Lahna competed in the Marathon of the Sands in his homeland, a grueling six-day foot race across the Moroccan Sahara.
''It's hard, the marathon training,'' he said. ''It's a dream I've had since I was little. It's a big event in Morocco. I had a lot of family and a lot of people on Facebook supporting me. Still, every night I'm dreaming about it and it's waking me up.''
And with only a handful of paratriathletes in Africa, Lahna sees a great opportunity to earn a spot in the Rio Games.
He has thought about this for a couple of decades now.
''Every time I saw the Paralympics on TV, I became very sad because I wasn't there,'' he said. ''It touched me, every four years I had that. I'm trying for Rio. ... There's time, but not plenty of time. Next year we will start the qualification process. Next year I have to be serious.''
Actually, his training regimen already is plenty impressive.
Lahna does two-a-day workouts every day but Friday, swimming in the morning - at either 5:45 or 6:45 before his wife goes to work - for an hour to 90 minutes, then runs or bikes in the evening once she is home for the night.
He also is the primary caretaker of his 1-year-old son, Adam, who comes along on occasion. During a workout this spring, Adam watched from his stroller. The baby, who turned 1 earlier this month, sucked on his thumb and made gargling noises.
They push on together each day.
Lahna met his Canadian wife, Ru Chen, when he attended a 2009 training camp in Atlanta and she was a student in prosthetics and volunteered for the event. She spoke French, and wound up as his translator, too.
''I wasn't the greatest interpreter, but we got by,'' Chen recalled. ''After that camp, we kept in touch through the Internet and the rest is history. We got married, had a baby, and now we've finally got the green card issues behind us. So far, it's worked out pretty well.''
Yet life is a tricky balancing act, with vacations scheduled around Lahna's competition schedule around the world. Lahna received his green card in December 2011.
Often people born with his condition in the United States will have the tiny foot removed. But, he said, they didn't know any better in Morocco when he was young.
''I can't amputate it now. I like it,'' he said with a grin.
When a friend told Lahna about triathlons in 2005, he asked for the details to be written down so he could research the event featuring swimming, cycling and a run at the end. He had already been a steady swimmer and hoped to make the Paralympics. He entered his first triathlon in 2008.
''It took me three years to do my first triathlon. At this time I didn't know that I could run, so I was looking for a racing wheelchair for the running leg, but I couldn't get one because it's so expensive,'' Lahna recalled.
Eventually, his friend, Patrice Ascargorta, worked to build him a prosthetic leg.
Lahna now swims at the on-campus San Mateo Athletic Club. He is training for his fourth world championships, in London this September. He was a silver medalist in 2011, then finished a disappointing seventh last year.
This weekend, he will compete in a paratriathlon World Cup event in Edmonton, then the New York triathlon next month.
''I've been swimming for a long time,'' he said. ''I just kick with my left leg. It's easier. All my energy and speed comes from my upper body.''
Lahna lacks the support system of the able-bodied Moroccan athletes, though he is doing his part to change that. His travel expenses for the world championships will be covered, but otherwise he is all but on his own. He does receive support in the form of a grant from the Challenged Athletes Foundation and is fortunate to have a volunteer coach who loves the cause.
''It makes me very sad,'' he said. ''I try to push for it just to be fair. I need support to continue to be competitive. I don't go just to qualify. This is my goal.''
A graphic designer for seven years back home before moving permanently to the Bay Area last year, Lahna will learn how to become a technician through a part-time job with a prosthetics company.
Lahna's father, Mustafa, is a taxi driver in Morocco. He had a disabled client who is a Paralympic swimmer, and used his example to motivate his son - the oldest of five children.
''He took me to the pool when I was 12 or 13,'' Lahna said. ''My parents treated me as a normal kid, which is something you don't see a lot in Morocco. When you have a kid with a disability, they treat them differently. ... I'm not like that. I thank my dad and my mom for that. It helped a lot. When I was little, we played in the street with other kids. I played soccer and rode a bike. I can't pedal, so I'd do the downhill.''
His brother, Salah, remembers a bike trip in which Lahna carried both of their gear on his mountain bike to make it easier for Salah during his first big ride.
''I saw in him a person who does not know the word impossible, a person who brings on challenges to achieve day after day,'' Salah said.
Still, there were plenty of occasions Lahna became frustrated with the limitations - and grew tired of the constant teasing he endured along the way.
''My mom told me many times that I came home crying because of that,'' he said. ''But I grew up with that. Everything's good now.''
