The most common and most likely answer to this crossword clue is the 8 letter word DISCUSES
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More clues leading to the result DISCUSES
Buddy explains!

The straight part
We know that "decathlon equipment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case decathlon equipment = discuses.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 DISCUSES mean?
DISCUSES noun- A round plate-like object that is thrown for sport.
- The athletics sport of discus throwing.
- (plural: discus) A discus fish (genus Symphysodon)
- A chakram.