The hiking stick is not a specifically mentioned component of the Junior test, however, its essentially required by "transitivity" that you learn how to use it before the test. The Junior test is performed in 10 knots or more wind, so you are going to need to hike out fairly aggressively at times while performing the required maneuvers on the various points of sail.
"Hiking" is the action of moving a member of the crew's body weight as far to windward (upwind) as possible, in order to decrease the extent the boat heels (leans away from the wind). By moving the crew's weight to windward, the moment of that force around the boat's center of buoyancy is increased. This opposes the heeling moment of the wind pushing sideways against the boat's sails. It is usually done by leaning over the edge of the boat as it heels. At Cal Sailing all of our Bahia and JY dinghies are fitted with equipment such as hiking straps and trapezes to make hiking more effective.
Hiking is integral to dinghy sailing, where the lightweight boat can be easily capsized by the wind unless the sailor counteracts the wind's pressure by hiking, or eases the sails to reduce it. The heavy keel on larger keelboats means that it is practically impossible to capsize them due to wind alone, but keelboat racers will still hike to prevent unnecessary heeling, or leaning sideways to leeward, because the more vertical in the water the keel is, the more effective it is at keeping the boat moving in a forward direction and preventing it from drifting to leeward, slowing the boat due to drag, and potentially increasing the distance the boat must sail when beating. Improper heel creates a tendency for the boat to turn off course, necessitating a correction with the rudder, which also increases drag. Sails use wind most efficiently when they are at a proper heel, another reason for controlling heel.
The dinghies at CSC have some extra equipment that facilitates effective hiking. Hiking straps made from strips of webbing hold the sailor's feet down, allowing them to lean back over the edge of the boat while sitting facing in. These simple devices are almost universal on dinghies (that do not have more complex hiking systems). Some sailors wear special shorts fitted with pads or stiff battens to help them hike more effectively and without tiring, and you definitely want shoes that will have a good grip on the gunwale.
At Cal Sailing most dinghies have a trapeze to allow the crew to increase their righting moment on the boat. These are wires attached high up on the mast, and fitted with a bracket that fits into a hook on a harness worn by the crew. This wire and harness then supports the crew as they stand and lean back over the water, pulling against the mast. On some boats, such as the Laser Bahia, the skipper uses hiking straps, and the crew uses a trapeze.
On most dinghies the tiller is fitted with a hiking stick, or tiller extension, which allows the skipper to steer the boat while hiked out.
PHOTO CAPTION: Here is Cal Sailing's Mike Yang showing perfect form while hiking out! This was only his second time sailing *ever*. He is an incredibly fast learner. And very comfortable on the boat. We definitely have a dare-devil on our hands here :-) In the above photo, notice the following: