Top 5 times on this course:
'16 Zachary Miller (28) 5:56:03
'16 Hayden Hawks (25) 5:58:07
'17 Tim Freriks (26) 6:02:26
'14 Sage Canaday (29) 6:07:52
'14 Dakota Jones (24) 6:12:20
I think there's a solid chance Walmsley breaks the record. He seems to be in good shape, though always hard to tell what real shape they're in, especially from strava. The downhill 5K time is fun, and he ran it on the backside of a moderately hard effort up as well. Not sure what you can say about that; some people handle downhills better than others and the slope/surface/turns is hard to quantify as well. My downhill 5K PR (during a longer run) is about 85 seconds faster than the flat 5K I ran in a race at a similar time, though I ran on a well-maintained highway with about 800' drop over the 3.1 miles.
For fun, though, this was part of a larger effort in which he ran up 2250' in 2.6 miles (a minute and a half off his PR but still faster than all others except Sage Canaday), then ran the drop hard. The drop has some variation in it, with another short/steep climb at the beginning, so from 8.2 (8989' at 1:14:22) to 12.7 (7235' at 1:34:11), or 4.5 miles in 19:49, dropping 1754' at 4:24 pace on a winding dirt road. Stats for the total run, 16.12 miles in less than 2 hours, but climbing over 2700', including some warmup/warmdown. Strava's GAP suggests it would be equivalent to a 25:00 5-miler. FWIW, the GPS track doesn't seem to show any data quality issues; that is, he really did run that fast coming down the road. As others have said, this isn't surprising and seems right in line with what he's run in the past.
It's fast, but not earth-shattering. He can't run that fast on the flat and from all I've seen, doesn't seem to want to. All this "JW is overrated" stuff is a letsrun phenomenon. He's the fastest ultrarunner in the U.S. for distances of 100k or less and he shows flashes of brilliance at 100 miles as well (with some notable failures, but then 100-milers are a class of difficulty far exceeding a marathon if you are going to red-line it for the whole thing), but he's jusrt an elite mountain ultra-runner (not the best, as we've seen at UTMB).
Marathon and shorter distance road running and ultrarunning are two different sports and we don't see anybody crossing the line between them and being dominant in both worlds. Don't expect JW would either, just like you don't expect to see Bekele, Farah, or Lagat start running trail 50-milers. Ultra fans have every right to slam Bekele, Farah, Lagat, and every other elite road runner for their inability and unwillingness to face a challenge where they might trip on a root and smash their face on the rocks.
