San Zhan (fighting for three times) Shi Zi (in cross) is a very typical Quan routine with firm and violent forces in Wu Zu Quan. It has got quite fierce vigor and powerful movement probably suitable for strapping people to practice. For the weak and thin, it is better to practice some agile ones that would be changeable in many different ways in actual fighting, such as "Da Jiao" (attacking at the comer) and "Shuang Sui" (double concessions). According to those fighting principles, while you are facing a stronger opponent with his higher and bigger body plus his stagnancy or slowness with his stepping and moving, you would win him even you are much weaker than him.
San Zhan Shi Zi is to practice your Kung Li and actual fighting technique with the cooperation of your breathing. Finishing your practicing, you will feel your abdomen getting heat slightly. This routine belongs to moving Kung-fu in Qi Gong in deed.
Among the San Zhan Shi Zi routines, there are several movements with strong attacking intentions, such as "Zhi Ma Xia Zhan Tan", "Da Zha" and "Bao Pai Dang". Playing these three movements requires your stances to be continuous, your handing movements to be quick. You have to attacking in hitting without any pause so that your opponent will have no time to react. Your movements have both attacking and defending containing both firmness and softness assisted each other. They are wonderful as a "secret technique" in actual fighting. Applying these movements, you could break your opponent's defense secretly.
Performing this routine, you should adopt the contrary breathing method. Your exhaling should draw out your Qi from your Dan Tian (an acupoint in your navel) with low and firm sound. Sending your forces by moving your waist flexible and having your handing movements swift would be quite powerful in any fighting.