The phrase "a downhill of" is not correct and usable in written English.
It seems to be an incorrect construction and does not convey a clear meaning in standard English usage.
Example: "The hike was a downhill of steep slopes, making it challenging for beginners."
Alternatives: "a decline of" or "a descent of".
Also, if there's a downhill on the other side of the uphill, you can use that to motivate yourself.
"Their lives are a futile uphill struggle conducted as a downhill, out-of-control tearaway," Richard Eder wrote here last year.
Unfortunately, on Monday, he lost control of his bike in northern Oklahoma on a downhill section of Highway 10.
The New Yorker, March 2, 1940 P. 9 Some Columbia University students went skiing on Broadway, from 116th Street North to 125th Street, a downhill run of almost half a mile.
James Dawson, a truck driver who managed to avoid being involved in the crunch, told CBC News that the accident occurred on a downhill section of the motorway covered in icy snow.
By the time I admitted myself to the hospital last June after a downhill period of six months, I felt isolated in my own pitch-darkness, even when I was in a room full of conversation and light.
By J. S. Hamilton and Russell Maloney The New Yorker, March 2, 1940 P. 9 Some Columbia University students went skiing on Broadway, from 116th Street North to 125th Street, a downhill run of almost half a mile.
SLCs can be either facilitative transporters, which transport their substrates down the gradient across the membrane, or secondary active transporters, which transport their substrates against the gradient across the membrane by coupling a downhill transport of another substrate.
Dy3K/δE3 mice (n = 4) were exercised for 30 min on a treadmill Exer 6M (Columbus Instruments) at a downhill angle of 15°.
Electrons could be transferred from these membrane c-type cytochromes to the terminal cytochrome c oxidases in a "downhill" oxidation of iron.
