"lose condition" is correct and can be used in written English.
It refers to the circumstances or requirements that need to be met in order for someone or something to lose in a competition or game. Example: The team's lose condition was not making it to the playoffs, so they worked hard to improve their performance.
He was, for two years, playing without big motivations, training without big motivations, and when you do that you lose condition, sharpness and even appetite.
For a gymnast, even a brief holiday can be a source of immense regret; they lose condition quickly, and it takes weeks to regain it.
This causes Nguni cattle to, minimally, lose condition, during periods when feed resources are scarce.
In landscapes which lack fiina, even when there is sufficient forage production, for some inexplicable reason livestock might continue to lose condition, thus forcing the herders to move to other areas, where better conditions might exist.
As the rut progresses, competition from more dominant, prime-aged males decreases as they lose condition, get challenged by subordinate males, and sometimes leave traditional rutting areas [49] [51].
If breeding behaviour is energetically costly then males should lose condition between their first and their last night in the chorus, unless they can compensate by increasing energy uptake.
In the 21st-century, explorers are losing condition.
"In the UK, we are already seeing common toads losing condition and experiencing reduced survival.
Her once vigorous body began to deteriorate, the muscles wasting and tightening, her heart and lungs losing condition.
Excessive dosage of KEA can cause large expansion of concrete even under the water losing condition.
During the breeding season, the male loses condition as he spends little time grazing.
