I try to use some locking whether joint or body in every class that I teach. Working and training with locks gives us many learning opportunities in addition to the effectiveness of the actual technique during physical encounters. Breathing, fear, tempering, physical and verbal communication, pride/ego and tension moderation among others are all aspects that are worked while exploring the locks for both the people applying the locks as well as the people being locked.
Breathing, the core of living, is something that should always be looked at while training. When exploring locks it is interesting to see how many times not only the body part gets locked but at how often the breathing of one or both people exploring the work also gets locked and trapped. It is very interesting to be able to catch yourself in that suspended breathing mode and feel the physical psychological and physiological changes that occur when and if you can restore your breathing. This exploration is best done slowly and most importantly honestly. Honestly meaning that both partners are working slowly, one is learning what the lock is doing physically mentally and spiritually to them while the other is learning what applying the lock is doing to them mentally spiritually and physically. If the locks are applied lightly, or if the person taps before the pain is actually felt then both are robbed of valuable learning, this is why slow and steady is best giving both time to explore more completely all that is going on.
Fear, one of the tests of living, is also something that should when it occurs be appreciated valued and understood. Often students of martial studies initially come to the arts from a fear motivational outlook. Others are athletes who have in past sporting endeavors suffered injuries. Ankles, knees, eyes, elbows and neck injuries are very common among athletes. Most everyone has had to deal with a sprain of some kind or another, tripping and falling in the parking lot, tripping up or down the stairs at work or slipping and falling on ice can all easily produce breaks and sprains both as the tripping slipping occurs and also to the arms as many brace on impact (almost never a good idea). If we approach locking as a means of exploring fear we can gain many benefits. For those applying the locks some will feel excessive empathy for the person they are applying the lock to, others will harden their hearts put on a stern face and demeanor. Still others will adopt a jocular disposition, while others avoid locking all together. All are a means of avoidance and symptoms of fear and any time fear is noticed it should be appreciated valued and understood. By understanding the origins and reasons of our fear we can gain knowledge on how to not let that fear negatively affect us and all opportunities to gain this knowledge should be cherished. LOL especially so during training when the consequences and goals of the training are hopefully growth and understanding. Learning how to deal with the spikes to our psyche caused by one kind of fear teaches us how to better respond positively to other fears and disruptions.
The surviving of one test better prepares us to endure future tests, tempering. We can if we train properly honestly and consistently begin to temper our bodys mind and spirits safely so that we may better endure whatever future tests and challenges that living brings us. That we will all face some kind of hardship in the future is a given. Realizing this, we can try to insulate our lives so that we limit those challenges but if we are honest there is often only so much we can control to limit the upcoming challenges we will face. Joint locking allows us to better understand many things, fear and pain being two of the simplest (but not easy) to explore. A training partner, one who is willing and able to apply the lock honestly albeit slowly in a measured manner and one that does not immediately release it but can hold it steady while the person is exploring and fully experiencing the range of emotions and physical manifestations that having the lock applied causes and brings up should be cherished and they are worth their weight in gold for the lessons that can be learned in this type of training are immeasurable. As well, having a partner that will let you apply a lock honestly to them, let you slowly feel the pain build up in them, let you closely observe as they internally struggle to deal with the fears emotions and past traumas/injuries allows you to learn to deal with your own issues about applying immense pain to another human being, and if you have no issues well
that is an issue. Working locks lets both partners work on their own tempering simultaneously while helping their partner work on their tempering.
Communication occurs thru many mediums and at many levels. For most people (attorneys, politicians and conmen being some of the exceptions) and most circumstances the clearer the communication the better. Communication can occur thru many different mediums and at many different levels. A child instantly knows at first sight which parent to ask for a favor without having to first talk to them, most workers can tell on first sight if their boss is having another bad day or is having a good day, a person can tell when their dog wants to go out to decorate the neighbors flower bushes or just wants some attention. An instructor can quell a student outburst with a look and a student can imply understanding or confusion to the instructor without having to verbalize it. We can communicate through written words, pictures, verbally and through touch. Communication is two way giving information and the receiving information. All communication requires practice to become more and more effective. Whether we practice writing or giving speeches or playing music the more that we do the better we get at it. The same is true for communicating through touch and body contact. Massage is a great means practice communicating thru touch. The same way that a very experienced auto body technician can feel the difference between very thin sheets of metal by merely a touch, or a musician can make music with their hands martial artists also need to educate their hands and bodys to communicate. If you think of your hands and fingers like stethoscopes you can gain all kinds of information from your training partner. Are they excessively sweating, how fast is their heart going, are they extremely tense, ill or injured. You should not need your eyes to see these things if you can touch them with educated hands. The clearer that you can read your partner/opponent the better you can respond to what they are saying at the same time, understanding this, a person can cloud and try to silence the information that you are sending to your partner/opponent. People that are excited and loud are the easiest people to work frankly while people that are calm centered and quiet can be extremely difficult to work. Working on joint locks gives us an opportunity to educate our hands. We can learn to feel when the lock is truly on; we can feel all the way thru the lock into the entire body of the person being locked. As the person being locked we can learn to quiet and smooth out the spikes in our psyches, can learn to separate the local temporary pain of the lock from whatever work we must do. We are both trying to become more sensitive to the volume of the communication both giving and receiving. Ever been in a dark room with somebody and everyone is whispering yet there is that person that seems to be hollering, ever been out shooting and afterwards had a conversation with somebody while still wearing your hearing protection? We as martial artists do not want to be the person yelling when a whisper will suffice nor do we want to be so hard of hearing that we miss what our opponent/partner is telling at us. Anytime we make physical contact (including striking) with our training partner we should be attempting to educate our hands and quiet our bodies, locking gives us excellent opportunity to practice this.
Are we so proud that no lock can be applied; are we so good that we can lock anyone anytime? I doubt many that have practiced martial arts for any length of time believe either of those two statements, yet we all have pride and ego. Working joint locks gives us great opportunity to experience this. When applying a lock to our partner do we feel excessive pride at forcing them to tap out? When we once having to tap out do we feel excessive burden to our ego at being made to tap? Ever been frustrated at an inability to make a specific lock work? It does not have to be extremes, but if we train honestly and take the time to really analyze what we are experiencing internally it gives our pride and ego practice on being observed recognized and understood and better moderated. Dont think you have any issues with pride or ego then chose for your training partner somebody you do not like at all, somebody you feel some contempt for and do the drills but pay attention to more than the wait until it is your turn LOL.
Tension, lifes gauge. We can become physically mentally or spiritually tense (or any combination of the three) at the merest whisper of sound, the slightest of touches or the faintest of memory. Whether youre applying the locks or having the experience of having them applied, by paying attention to excessive tension in both yourself and in your training partner we can better learn how to recognize and deal with the tension that comes up in our daily lives and practices. Tension is a symptom of a greater issue. We can either treat that symptom or we can treat the issue causing the symptom. No matter which route that we chose though we must first recognize the excessive tension. Once recognized then we can begin the work of cleansing it if it is our tension or manipulating it if it is our opponents tension that we see/feel. To get better at both recognizing and cleansing excessive tension we should practice it and yup working the locks if we take our time and train honestly gives us great practice in recognizing our and our training partners tension and practice in identifying the sources and cause of the tension.
Meh, on the street depends on the context and the skills and dangers the opponents demonstrate but good to know incase the opponent hasn't heard that they do not work and attempts to throw one on me LOL
For training? yes to both questions. They are good tools.
Regards
Brian King
To relate a story with this I was teaching at a seminar a couple of years ago and just picking random people to show the techniques on. One kid was uber flexible and of course double jointed. I did not know that but when he adapted to what I was doing and moved to another place I could feel it before he went there and walla I was already waiting and the trap/lock was put in place so while it changed what I was showing it also showed everyone to be flexible in your approach to locks and roll with the flow and keep ahead of the game. So it may feel wrong but do not stop or freeze just roll to the next area/movement and let the next thing happen. You of course already know this so I am just relating for other peoples benefit! 
