Grinning mischievously, Juanjo Urbizu dons a baseball cap, tucks his T-shirt neatly into his sweatpants and adjusts the velcro straps on his elbow pads before positioning his skateboard on the bowl's edge, ready for the "drop".
Other skaters, dressed in baggy streetwear, crane their necks while the sun casts long shadows over the graffiti-covered concrete.
Urbizu's attempt at a gnarly trick draws stares because the athlete is a sight to behold, wheeling around the unassuming skate park in northern Spain having just turned 88.
For the cheerful octogenarian, each skating session begins by carefully clearing the square bowl of pebbles to guarantee a smooth ride.
"My bones are special," he chuckles in Bilbao's working-class neighborhood of Begona. "Though I touch wood."
In a rapidly ageing country, where more than half the population is over 44, the demographic shift is increasingly becoming a topic of national debate. Economists fret over the welfare state's sustainability when government data shows there are 137 people aged 64 and older for every 100 under 16.
But Spain's generally warm climate is conducive to outdoor activities and studies have proven the importance of physical exercise in bettering the quality of life and reducing the risk of disease for the elderly.
Urbizu took up skateboarding aged 70, partly because it was cheaper than his beloved snow sports. He finds the extreme sport more than just a way to stay fit, also offering an escape from monotony.
"By breaking the routine, you bring something new to everyday life, and that gives you a sense of rest," he argues.
For other people his age considering taking up skateboarding, he advises do it little by little.
"Falls here are truly bad, much worse than in the snow. Anyone who does something like this should wear full protection."
