A recurve bow is a form of bow efined by the side-view profile; in contrast to the simple longbow, a recurve bow has tips that curve away from the archer when the bow is unstrung. By one technical definition, the difference between recurve and other bows is that the string touches sections of the limbs of recurve bows when the bow is strung. A recurve bow stores more energy than an equivalent straight-limbed bow, giving a greater amount of cast to the arrow. A recurve will permit a shorter bow than the simple bow for a given arrow energy and this form was preferred by archers in environments where long weapons could be cumbersome, such as in brush and forest terrain, or while on horseback. By contrast, the traditional straight longbow tends to "stack"—that is, the required draw force increases more rapidly per unit of draw length as the string is drawn back.