The let-off itself is the result of the cam profiles having passed center and approaching a condition very similar to a cam-lock. It can also be hard-drawing with a very fast build-up to peak draw-weight, a long plateau where weight is maintained, and a quick let-off with a short valley. A compound bow can be soft-drawing with a slow build-up to peak weight and a gradual let-off with a long 'valley' at the end. By manipulation of the shapes of these cam tracks, different draw-stroke profiles can be created. As the bow is drawn, the ratio of bowstring pay-out and cable take-up relative to limb-weight and leverage of the cams changes. Each of a compound bow's two cams features two tracks: an inner track which connects to the opposite limb or opposite cam through cables, and an outer track through which the bowstring runs. The cams are eccentric rather than round, and so their effective radius changes as they rotate. The pulley/cam system also confers a benefit called 'let-off.' As the string is drawn back, the cams rotate. The higher-rigidity, higher-technology construction also improves accuracy by reducing the bow's sensitivity to changes in temperature and humidity. This rigidity makes the compound bow more energy-efficient than other bows, as less energy is dissipated in limb movement. The pulley/cam system grants the user a mechanical advantage, and so the limbs of a compound bow are much stiffer than those of a recurve bow or longbow. In general, compound bows are widely used in target practice and hunting. In modern archery, a compound bow is a bow that uses a levering system, usually of cables and pulleys, to bend the limbs. Archer Erika Jones shooting a compound bow.

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