If you've hiked on Vancouver's North Shore, you've almost certainly encountered the Baden-Powell Trail.
Spanning 48 kilometres, the B-P Trail stretches from Horseshoe Bay to Deep Cove, crossing the slopes of several mountains along the way.
I've hiked much of it in portions and aim to eventually complete the route.
However, some people like to run, rather than walk, this trail.
Perhaps the most daring of this bunch were out in force today (July 9) for the 23rd annual Knee Knackering North Shore Trail Run, which follows the B-P Trail.
This ultramarathon race sees more than 250 trail runners tackle a course that ascends 8,000 feet and descends 8,300 feet, topping out on the summit of Black Mountain en route.
Today's winners: Aaron Heidt of Vernon in the men's race and Louise Oram of Vancouver in the women's race.
Heidt finished with a time of four hours and 53 minutes, while Oram clocked in at five hours and 41 minutes.
For hikers like me, it can take around that long to do one section of the B-P Trail, say from the base of Grouse Mountain to Lynn Canyon.
So, congratulations to everyone who finished today's Knee Knacker.
This training run video offers a taste of what it's like to take on the Knee Knacker.
You can follow Stephen Hui on Twitter at twitter.com/stephenhui.