The phrase "a difficult run" is correct and usable in written English.
It can be used to describe a challenging experience while running, whether in a literal sense (like a physical run) or metaphorically (like a difficult task or situation).
Example: "After completing a difficult run through the hilly terrain, I felt a great sense of accomplishment."
Alternatives: "a challenging run" or "a tough run".
"It was not a difficult run but because it rained, it was quite icy.
"We have been having a difficult run and minorities get a lot of publicity in this country.
Photo: The yachts in the Volvo Ocean Race reached New York Harbor yesterday after a difficult run up from Baltimore.
It is a difficult run and a true test of their resolve but Wenger will know that if they emerge from it unscathed their run-in looks the best of any of the top five sides.
This was also the night when Coutinho identified himself as the club's new penalty-taker, ending a difficult run during which Firmino, Salah and James Milner, twice, have failed to convert from 12 yards during games at Anfield in 2017.
"I would be excited for that person – to give the Democrats a difficult run – just because they would be a worthy opponent".
The minister for Europe, Pierre Moscovici, faces a difficult run-off in Montbéliard, as does the justice minister, Marylise Lebranchu, in Morlaix.
The result lifted Derbyshire out of the bottom two, one point above Somerset, and will be crucial as they prepare for a difficult run-in.
Only North-east neighbours Middlesbrough and seemingly doomed West Bromwich Albion are below them and with only eight matches to play and a difficult run-in to come, Newcastle are two points from safety.
But the Socialists face a difficult run-off in a string of other towns where they did not score as highly as they had hoped, including Toulouse, Amiens, Reims, Saint-Etienne, Quimper and Caen.
There's no two ways about it: this was old-fashioned red-blooded populism, a budget laying out the goodies in advance of what is likely to be a difficult run-up to the elections due in 2014.
