Could anyone explain me please?
You must ask a little bit more elaborated manner, like where you heard this emergency strategies or did you try googling it ?
Investopedia has some articles on emergency funds :
http://www.investopedia.com/terms/e/emergency_fund.aspFrom the terms "emergency"+"strategies", it sounds like PLAN-B :
In the case of negative market, I guess these strategies will be dealing on how to prevent more losses as per my understanding.
I usually will accept losses rather than looking for any plan-b. I do exit my positions at stop-loss. But some traders do try to recover those losses immediately and they do call those trades as plan-b. But I do not prefer them.