clarify with an example
A short stack is considered to be 30BB or less by traditional thought. In turbo tournaments, however, the average stack is often around 20BB or less at bubble time.
In this type of situation, most hands will be won either preflop or right after the flop; hence my suggestion to cbet the flop relative to your stack size. Any time a cbet or a standard pre-flop raise would cost you more than 1/3 of your stack go ahead and ship if you have position.
Blinds are 400 / 800 ante 100 at a nine-handed table, you have 10,000 chips and pick up JJ in the hijack seat. You raise to 2,000 and the Small Blind, who has 30,000 chips, floats. Flop comes King, Ten, Eight with two spades. Small Blind checks.
At this point you have 10,000 - 100 ante - 2,000 raise = 7,900 chips. There is your 2,000 + the SB 2,000 + the BB 800 + 900 in antes = 5,700 chips in the pot. A standard cbet would be half pot, or 2,850 chips. Your stack 7,900 / 3 = 2,633 chips, which is less than half pot. Go ahead and shove.