Originally Posted by Dchiefransom

If you set the release tension very low at first, do not, I repeat, do not stand and try to pedal hard. Low tension pedals and starting to sprint are the reason I've seen so many riders go down by themselves when their foot unclips accidentally.
What I did was find a steep hill, and keeping tightening the tension until my foot stayed clipped in while climbing hard. Then I went two clicks tighter.
By all means, get the shoe cleats that release in both directions.