After having looked at 1 Cor 5, 7 and some related passages, 1 cor 9 is likely to speak about similar subjects as these chapters, and Paul seems to elaborate on the puroposes of the lives of people and the way in which to maximize the good effects of it.
Lets start with quoting the greek, and thanks to the Goshen bible study site and the Perseus greek lexicon, references to strong's notation and a solid greek lexicon are also available.
1 Cor. 9:25,26
[KJ 'striveth for the mastery', from SL ago^n:
gathering, assembly, struggle] 
[KJ 'temperate', from SL egkrate^s:
in possesion of (power), holding fast, with a strong hand]
[LJ 'corruptable', SL phtheiro^:
destroy, perish, corrupt, bribe, wander]
And [1161] every man [3956] that striveth for the mastery [75] (5740) is temperate [1467] (5736) in all things [3956]. [3303] Now [3767] they [1565] [do it] to [2443] obtain [2983] (5632) a corruptible [5349] crown [4735]; but [1161] we [2249] an incorruptible [862]
[KJ 'run', SL trecho^:
'run']
[KJ 'uncertainly', SL ade^los:
'unseen, invisible,by unknown hand, unintelligable']
[KJ 'fight', SL pukteuo^:
'box, spar; strike with the fist (on the head), fight']
I [1473] therefore [5106] so [3779] run [5143] (5719), not [3756] as [5613] uncertainly [84]; so [3779] fight I [4438] (5719), not [3756] as [5613] one that beateth [1194] (5723) the air [109]:
The last word
translated as to beat is described in Scott Liddel as: