Aikido Arts of Shin BudoKai blog on utility of joint locks. The whole article may be read here. Please pay a visit.
As a young man I trained very hard in Yoshinkan Aikido, and for a while worked in security on the midnight shift at a Detroit area hotel. Months of boredom would sometimes be punctuated by .. you name it: fights in the bar, parties getting way out of control, fights in the parking lot and so on. It was our job to hold down the fort until the police arrived. Sometimes the hands on the clock can move very slowly; like that New Years Eve one of my co workers (the biggest and toughest one of the bunch no less) almost got throw off of a balcony... but I digress.
I always emphasize that joint-lock techniques cannot be viewed as a means to lock a particular joint. This narrow focus causes many problems. One, a person is attacking you, not a joint. If you simply focus on one joint, the rest of the person is typically more than happy to tee off on you as a reward for not paying proper attention to him/her. Two, a conscious intent on your part is easy “read” by the other person, which then results in that person moving in a manner to counter the joint-lock. I emphasize that a joint-lock should result in a cascade of locking joints so that the attacker’s frame (spine and hips) is negatively impacted so that effective movement becomes almost impossible. This can only occur if one’s intention is directed at the person’s center and not directed towards the initial joint that you seek to lock. Before this can happen, you must do something to off-balance the attacker.
The act of off-balancing the attacker serves to effectively neutralize the effective strength of the attacker. It is very important to understand that the human body has a primary directive to maintain dynamic equilibrium (maintaining balance). When a person’s body is off-balance, the body automatically and pre-consciously re-directs all available body resources towards re-establishing dynamic equilibrium. I always demonstrate this phenomenon by having a person stand with excellent posture and hold an arm out straight as strong as possible. You push down on that arm to gauge the strength. Then have that person do something that negatively impacts that posture ( eg. tilt head in any direction) and push on the arm again. The difference is always striking! When the person’s functional strength has been significantly curtailed, it is easy to begin to execute a joint lock technique. As long as you increasingly impacting the stability of your attacker through the execution of a joint-lock technique, the person should not be able to effectively counter the technique and that person should not be able to re-establish a stable posture or base to work from.