Human-powered watercraft include prehistoric, historic and well-known traditional and sporting craft such as canoes, rowing boats and galleys. The term "human-powered boat" is often used for more modern craft using propellers and water wheels for propulsion. These can be more efficient than paddles or oars and especially allow the use of the leg muscles which are generally stronger than arm muscles, even for non-athletes. Competitive rowing boats use sliding seats to engage the legs for propulsion with an oar for this reason, but require considerable skill to use efficiently. In addition, there is little skill required for forward propulsion while looking forwards and craft such as pedalos are popular at resorts.