Refers to the physical state of having an empty stomach, often implying hunger. Used in expressions like 空き腹にまずいものなし (nothing tastes bad on an empty stomach).
Exercising on an empty stomach is not good.
As they say, nothing tastes bad on an empty stomach, so everything seems delicious.
Standard kanji spelling.
Mixed kanji-kana spelling; less common but still used.
Compound of 空き (empty) and 腹 (stomach). The reading すきはら is standard; すきばら is a voiced variant (rendaku) sometimes heard in speech.