The Second Road (Er Lu二路) of the Eight Diagrams Four Roads form turns and runs sideways from the starting position, East and West. This road deals with a different type of stepping then the first using short stances and a different type of forward power.
Large stances like those found in the first road are used to teach beginners about body structure and posture in an exaggerated way so it is easy to see and correct. For instance the bow stance (gong bu弓步) is a large position that teaches the importance of a straight back and rearward leg to act as an anchor for incoming or outgoing force. Pushing on someones chest while they stand in a bow stance should result in fighting against their back leg which is already aligned with the incoming force. A very power way to stand!
However in motion a player does not always have the time to take large steps or stances and so the idea of training them comes to light. Large exaggerated stance work at the beginning allows for a person to find correct structure and then learn to shrink that structure into smaller positions that will then have correct posture as well. Perhaps they won’t be as strong but they will definitely be trained and powerful. In the second road we see these shrunken stances being trained to create smaller steps and more mobility.
Road Two begins in Horse stance and then turns powerfully to the left. Drawing back the leg into the cat stance is done with the foot dragging on the floor training not only closing the groin for a pulling sweep but remaining rooted and in contact with the earth while doing so. This means that it is not only dragging on the ground but should have a substantial amount of pressure on the ground as well as it moves.
Next the stomp kick is done with the whole bottom on the foot while reaching through the heel, downwards on a forty five degree angle. In application this is meant to pin an opponents foot to the floor while stepping on their shin bone to either make them fall or dislocate their knee. The placing of the foot down after the kick can be down gently but still requires force to go through the foot as though pinning an opponents leg to the ground.
Mud stepping is the equivalent of the tiger step from the first road, driving the force of the legs movement directly forward through anything in its path. When stepping in small steps like seen in road two this becomes a type of stepping from baguazhang training. The full name of the step is “Wading through Mud Step” (Tang Ni Bu 趟泥步 ) and means to move as though your are up to your waist in mud. This means you cannot simply pick up your leg and move it forward but instead have to drag it through the heavy mud as though you had a great weight tied to your ankles. There is a lot more to be said about this stepping in bagua training but using this bit of information for road two should improve training. Walk forwards as though you are crashing your shin bone directly into an opponents to destabilize their stance.
The next movement is to turn and stand in Crane stance. The most important part here is the pulling of the foot back from the mud step and upwards into the Crane again training power for pulling an opponents leg out from underneath them. This type of squeezing or pulling force is difficult to gain and so methods fro training it appear in the form many times. The side kick is aimed at knee level of an opponent and then pulled back with the same type of force as the movement before. Should you miss the opponents knee with the kick, hooking the rear of their knee with your foot will allow to return to crane stance pulling their leg with you.
The heavy step from Crane into horse is a short version of an outside crescent kick and as such is focused on two things. One the movement of the hip to lift the leg upwards and train power in the hip joint (kua) for pulling and two the intentional transfer of weight from the body through the stepping leg to use it to power the stomp into the horse stance. This movement in the form should make a sound as your foot hits the floor training directing power downwards out of your foot and massaging the acupuncture point YongQuan 涌泉 (Kd1) on the bottom of the foot. The vibrations from the stomp help the kidneys move slightly and as such helps to keep them healthy. (Again more can be said about this in training but being sure to place the foot down audibly and flat so you do not injure your heel are all important for now).
The step behind the knee to unicorn should be done deep enough to create a good unicorn or crass stance. This is a place where students tend to cheat by taking a small step and avoid the lower difficult stance. This stance is hard on the legs and trains strength very well and it is worth taking a breath while holding it in the form. Finally the turn around to horse stance should be done forcefully while turning on the balls of the feet. Another method of training that can be done on this turn is to think about using the forward moving should as a shoulder strike and placing your mind there to create power. This way in the first road you have trained elbow strikes as you turn and in the second road shoulder strikes. The other side of the form is identical just in mirror image.
Hope this helps!