The most common and most likely answer to this crossword clue is the 8 letter word GYMKHANA
I've seen this crossword clue in The Daily Telegraph
G
Y
M
K
H
A
N
A
More clues leading to the result GYMKHANA
- Sports meeting for health club at which foreign prince gets first aid
- Sports event‘s reportedly why MK Dons land in Africa
- I pulled out of mad haymaking contest you have to be up for
- Setter’s backing king in country that’s mounted challenges
- Sports meeting, close to fifty km, running over in African country
- Exercises at Eastern inn before a riding event
- Primarily young mares king enters in African state event for them?
- T
Buddy explains!

The straight part
We know that "contest you have to be up for" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case contest you have to be up for = gymkhana.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GYMKHANA mean?
GYMKHANA noun- A competition where riders and horses display a range of skills and aptitudes.
- A place of public resort for athletic games, etc.
- A meeting for such sports.