for a good lead dog are intelligence, initiative, common sense, and the ability to find a trail in bad conditions. Swing dogs or point dogs are directly behind the leader (one dog if the team is in single hitch). They swing the rest of the team behind them in turns or curves on the trail. (Some mushers use the term swag dog to denote a team dog.) Team dogs are those between the wheelers and the swing dogs, and add power to the team. A small team may not have dogs in this position. Alternatively, the term may be used to describe any dog in a dog team. Wheel dogs are those nearest the sled and musher, and a good wheeler must have a relatively calm temperament so as not to be startled by the sled moving just behind it. Strength, steadiness, and ability to help guide the sled around tight curves are qualities valued in "wheelers." Originally, sled dogs would run in either one or two straight lines, depending on how many people were driving the sled (two lines if there was one person, one line if there were two people). However, now, all dogs run in two lines, even if there is more than one person. Equipment Many pieces of equipment are useful or necessary for driving sled dogs, depending on the sled or vehicle, terrain, weather conditions, size of the team and dogs, speed of the run, and other factors. Harnesses Harnesses are worn by dogs used in mushing to allow them to run and pull with freedom of movement. They are designed to distribute pulling weight evenly over the body, and are made of material that is durable and lightweight to varying degrees. Many different styles of sled dog harnesses exist for specialized styles of mushing and dogs, with many outfitters evolving and updating designs and materials to fit the needs of different mushers. The most commonly used styles include X-back (also referred to as racing harnesses), half-back (used more commonly in mushing where the line angle is steeper such as canicross and bikejoring), and spreader-bar/freighting (used for hauling heavy loads low to the ground, or by wheel dogs on teams). Harnesses have certain requirements for some competitions such as weight pull, to ensure the safety of the dog in their task. Sleds Dogsleds can be a variety of styles, ranging from highly traditional wooden sleds