Welcome to the Capital Mixed Martial Arts & Elite Fitness Training Network, an online resource for members and guests participating in several of our core programs: CrossFit, Royce Gracie Jiu-Jitsu, Muay Thai and Kid's MMA. Please use this page - featuring all of our programs - or select a specific program from the menu below and bookmark that page.
Disclaimer: I am not a doctor. I am a fitness advocate, Marine Martial Arts Instructor, former Body Builder and Certified Fitness Trainer by ISSA. Any of the techniques listed below when used improperly can badly injure or kill you. Consult your doctor before beginning any weight cutting or fitness regimen.
Making weight has two phases. Long term and short term.
In the long term, weight and body composition change through training and diet. Regardless of your training/cross-training regimine (CrossFit, Body For Life, sparring, mixed, etc…) or diet (Zone, Body For Life, South Beach, etc…) your body will condition itself to the tasks that you present it.
Body Composition: Through training and diet muscle mass will be maintained or increase, and body fat will be maintained or decrease. Train hard, eat smart, and you will experience positive results. That being said, on fight day, if you are a man you want to be right around 10% body fat, and if you are a woman you want to be around 12% to 14% body fat. These body fat percentages tend to maximize performance for combat sports.
For the short term, we get away from improving overall body composition and address ‘cutting weight’. Why cut weight? Generally speaking, fighting a smaller guy is better than fighting a bigger guy. If you weigh in as a ‘smaller guy’ you will fight smaller guys, which means you will be more likely to win. Of course, everybody knows this, so, everybody cuts weight. At this point it becomes a question of:
1) How much can someone cut?
2) How much of a price will someone pay in PERFORMANCE?
As a serious competitor, cut the amount of weight required to weigh-in to achieve a size disparity between you and your opponent, WHILE preserving maximum athletic performance.
Before moving on, let’s summarize what we have so far. In the long term, change your body composition through training, cross-training and proper dieting. Then, in the short term, before a competition, ‘cut weight’ so that you weigh-in to a bracket/class below your actual weight. All the while preserving maximum athletic performance.
Planning to properly cut weight:
First, get your head right. What are you cutting weight for? Is this your first BJJ tourney? Your first MT match? Your first time ever trying to cut weight? Your second pro fight? What I’m saying is you need to make a risk/benefit analysis before you choose to cut. I’ve got a news flash for you… if you’re competing in a non-rated local blue belt tournament, and try to ‘cut a ton of weight’ to get into a lower bracket, you’re wasting your time. If this is your first amateur MMA fight, and you ‘cut a ton of weight’, you’re jeopardizing your performance to fight a slightly smaller guy. The trade off sucks. The way I look at it, if this fight isn’t your profession, or a stepping stone towards that, is DON’T try to cut a lot of weight.
Second, understand the timeline. How much time is there between your weigh-in and your competition. If it is more than about 20 to 24 hours then you can dabble in short term weight cutting. Anything less than that and I wouldn’t fool with it.
Third, you will need to practice. As with everything in the fight game, don’t ever use ‘new stuff’ on game day. No new punches, submissions, sweeps, strategies…. Do all of that during your work up. Cutting weight is the same way. The first time you cut weight should not be when it matters. PRACTICE FIRST! People respond differently to cutting, so figure out how you will respond before it matters or else you run the risk of flushing a perfect training cycle right down the crapper.
Fourth, understand your target. If you try to cut much more weight than 8% to 10% of your total bodyweight then you are entering dangerous territory. Not that you can’t get the weight off, but you may not be able to put the water back into your system before game time. Poor hydration means poor performance!
Fifth, know what will happen if you screw up. In the UFC fight between Travis Lutter and Anderson Silva (February 3, 2007), Lutter not only failed to make weight, he cut either too much or with improper technique. This resulted Silva submitting Lutter via triangle choke in round 2. I am convinced that Lutter failed to adequately and intelligently cut weight which resulted in him ‘running out of steam’. So, you must be careful as this is powerful magic.
The science of short term cutting weight:
Short term weight cutting takes place 1 week prior to your weigh-in. As you taper training, you ramp up cutting. This secret is to ‘trick’ your body into thinking that super hydration is the new norm. Then, when you stop drinking as much water, your body continues to urinate large amounts… and the weight just falls off.
Seven days prior to your weigh in, DOUBLE water intake and take in half your usual amount of sodium. I’m talking about 2-3 gallons of water per day (yes, it can be done), and eat less than 400mg of sodium in per day. This gets your system used to being super hydrated, while flushing sodium. (Sodium is bad because, as every chic in the world will tell you, it makes you retain water. Specifically, it makes you retain water in the subcutaneous layer between your muscle and skin.)
KEEP EATING! Stick with your normal diet for your work up.
Four days prior to your weigh in, keep your intake HIGH and cut sodium to minimum levels (less than 100mg per day). Also, start supplementing your diet with potassium. Take the recommended dose on a potassium supplement label. Do not get crazy with this, just take what is recommended.
KEEP EATING!
Three days prior to your weigh-in, cut your water intake in half (minimum of 1 gallon). Everything else stays the same.
KEEP EATING!
Two days prior to your weigh-in, cut water intake in half again (minimum of 64 oz). Everything else stays the same.
KEEP EATING!
One day prior to your weigh-in, cut water intake in half again (you will drink about 32 oz of water on this day). Everything else stays the same.
KEEP EATING! (You should be about halfway to your goal on this day).
On the day of your weigh-in, sip water ONLY. Also, IF REQUIRED, eat about half of what you were eating on every other day (keep protein up, this helps to draw water out of you).
Here are some final notes about weight cutting:
- Your weight loss will be gradual at first, and will become dramatic between 36 to 48 hours before your weigh-in.
- Do not freak out when you’re 3 days out and are still 10 lbs over weight. The night prior to weigh-ins you will lose a ridiculous amount of weight.
- If you are ON WEIGHT the day prior (or any other day), keep doing whatever it is that you’re doing. You need to be AT the prescribed weight for 1 minute during this whole fight work up…and that minute is the moment of weighing in. During every other minute you can be any weight you want.
- You will feel crappy for a couple of hours some time during the last 2 days of weight cutting. It should last only a few hours, probably right before you weigh in. If you feel very sick, drink water and have something to eat.
- If on the day of your weigh-in you are not even close, there are techniques you can use to lose additional water weight in a short period of time. I’ll list here some general categories, but will only address specific details in a face to face conversation. THESE WILL SIGNIFICANTLY INCREASE THE DANGERS ASSOCIATED WITH WEIGHT CUTTING AND I DO NOT RECOMMEND THEM.
– Exercise
– Sweat Suits
– Saunas
– Stopping water intake for more than 24 hours
– Stopping food intake
The last step, rehydration!
Congratulations, you made weight! But you are dehydrated, so now what? Well, you need to put that water back on, and here’s how:
Right after weigh-ins, drink a Gatorade type drink (32 oz or so). Slug it down, sip it, whatever is comfortable. After this, treat rehydrating by eating and drinking in your usual way. Chugging water won’t rehydrate you faster, instead it will only pass through you. Drink and eat normally, that is all.
Keep up this normal eating and drinking until 2 hours prior to your competition. You should have an empty stomach when you compete (maybe a little water in there), and you should be hungry, but not starving. If you are starving, and you still have an hour before your competition, eat a banana or an apple. Comfortable hunger is the goal.
Everything in this article is a plan only. Considering how we are all different, the plan might need some tweaks to fit you. And that is why you MUST PRACTICE FIRST!
If at any point you pass out, shit your pants, or otherwise lose your ability to function, you did something wrong.
This video below shows an awesome Jiu-Jitsu match between Fernando “Terere” Augosto and Marcelo Garicia. These are two of my favorite grapplers to watch, and doing so has helped my game considerably. While there’s a lot of great technique in this video, my goal in this post is to outline Terere’s passing strategy. He’s able to give Marcelo fits with a well-organized approach comprised of passes that allow him to attack in all directions and excellent hip pressure and placement. Pressure from the top is difficult to teach and learn, and although I do my best to cover it in class as often as possible, Terere is an superb example of how to use the hips when passing.
In many ways my description here is an oversimplification because Terere’s efficiency of movement, timing and improvisation are the keys to imposing his top game on Garcia. But, sometimes presenting things in an organized, a, then b, then c layout can help us work toward achieving the real Jiu-Jitsu that we aspire to. So, below is a broken down description of Terere’s top game in this match. This is one of my favorite passing sequences and this match has been instrumental in helping me improve it. Knowing these movements separately is easy, but Terere has the ability to use them appropriately in a complementary fashion, which goes a long way to explaining his success in this match.
1) 6:09 Starting stance (alternate side at 9:24). There are several instances of this posture, in which Terere places his right knee between Marcleo’s legs, his right hand on the lapel and his left foot planted away from his body. The knee keeps the guard open and the lapel grip gives him some control of the upper body. This posture gives the passer several options for how to pass, depending on how the opponent reacts. Watch Terere work to achieve this posture again, beginning at 7:32, and pay close attention at 7:34-35 as Terere changes the angle of his hips in relation to Marcelo by shifting to his left.
From the starting stance, Terere attacks the passes below based on Marcelo’s reactions. Importantly, Terere always stuffs one leg between his legs when he’s in the starting posture. He does this at 7:35 as he shifts his weight, pushing Marcelo’s right leg inside his own.
2) Hip drop to the left. Terere attempts this movement around the 3:28 mark. From the starting posture, if the opponent keeps the stuffed knee (in this case Marcelo’s right knee) high up, preventing the knee drive pass described below, you can switch your hips to engulf the knee. Terere combines this pass with threading the his arm, described next. From a starting posture in which your right leg is up your left leg is out (foot planted), this pass gives you the all-important option of passing to your right, whereas the knee drive and bullfighter options entail passing to your left.
3:34 Butterfly guard passing threading the arm around the legs. This pass works from butterfly guard or similarly, from the starting posture when the opponent places the top leg in front of your waist (either shin or as a butterfly hook). In some cases the opponent may do this on his own, whereas in others, the position can be achieved by the hip drop described above. Terere threads his left arm through Marcelo’s legs to force Marcelo’s legs together. He complements this grip with hip pressure. Note in 3:50-51 as Terere gives a fake, allowing his right side to be lifted higher than his left. This causes Marcelo to extend his right leg in an attempt to sweep. The more the leg extends, the easier it is to collapse the knees together, which is what Terere does by dropping his right hip to the mat at 3:52. Because Marcelo’s leg is more extended as this movement takes place, Terere’s hips engulf Marcelo’s leg and force his knee to the inside of Terere’s body, thus negating the lifting effects of Marcelo’s right butterfly hook. Once Terere has done this, he’s able to control Marcelo’s legs enough to hop to his left. Note his left foot placement at 3:55 helping to pin Marcelo’s bottom leg to the mat as he has released his left arm thread grip before hopping to his left. Essentially, Terere used his arms and hips to control Marcelo’s legs. Once controlled, he could continue to pin the legs with his foot, freeing his arms to gain more upper body control on Marcelo, resulting in taking his back at 4:02.
3) 8:11 Bullfighter’s pass. This pass is on of the options from the starting stance. Terere first achieves the grips he needs: left hand on Marcelo’s right leg and right hand on the lower lapel. He then shifts back toward the starting stance and steps back with his right leg, simultaneously pushing Marcelo’s right leg with his left arm. The setup also appears at 3:11 when Terere seems to have been thinking about this pass.
4) 1:48 Knee Drive Pass. Here, Terere holds the lapel with his right hand and controls Marcelo’s right sleeve with his left arm. He drives his right knee through Marcelo’s guard, to pass on Marcelo’s left side. In this case, Marcelo quickly defends by going to his knees, preventing the pass.
Enjoy the video, please post questions to the comments.
I enjoy exploring the dual nature of things*, and as such have recognized a pattern over the years with regards to students and their training goals.
Pattern A: Student immerses him/herself with regular training. They love being on the mat, watching YouTube videos, attending seminars, and chatting with friends and family about their art/sport. After a while, they decide to set a goal, maybe a competition, and work even harder to achieve it! Some set up a training cycle, visit with their coaches and training partners to develop a game plan, and take private classes to attack their weaknesses. Eventually game day arrives, and they compete. Win or lose, they are back on the mat the next week training, for fun, once again.
Pattern B: Student trains, falls in love with tales of expert competitors, fantasizes about the attention that others get when they compete and win, but finds her/himself lacking the desire to experience day to day training. They set a goal, and use it as inspiration to train more, but they easily succumb to temptations and distractions. They want help to stay on track, and look to their coaches and training partners for further inspiration.
When I was in my young adult years I enjoyed books like Zen and The Art of Motorcycle Maintenance, because they explored this duality. My favorite parable from my readings at this time was of a group of hikers who set out to conquer the Appalachian Trail. Some of the hikers fell in love with the idea of being able to tell the world that they were of the few who completed this long journey through wilderness and self-discovery. Others simply LOVED hiking, and saw this as the ultimate expression and testament of that joy.
So, at the end of the road, who was left from the group? Who finished the hike? Those who loved it. And what about after? In a couple of weeks they were back on some trail, somewhere, for a day hike, whether alone, or with friends and family.
~Jeremy Lafreniere
* While I do enjoy looking for the black and white, I strongly feel that most of us exist in the gray. We all experience a desire to be better, and at times goals do inspire (think New Years Resolution here!) But the real experts in life are those that enjoy the day to day process, without the constant need to reflect on the product.
Today Grandmaster Helio Gracie passed away at the age of 95. His son, Royce Gracie, quickly boarded a plane to be with family Rio de Janeiro.
I would like for us to celebrate and remember Grandmaster Helio Gracie for living a life full of passion, and providing us all with the opportunity to learn and train in the wonderful science of Gracie Jiu-Jitsu. Without Grandmaster’s pioneering spirit, and lifelong dedication to learning, training and teaching, we would not have the privilege we do today to study the system of self-defense, throwing and grappling that is now esteemed by martial artists around the world.
Rodrigo Gracie called me this morning to say that there are two ways to remember our Grandmaster. Some will close their schools out of respect, and others will train harder today than they have in a long time. Capital Jiu-Jitsu chose the latter, and today celebrates Helio Gracie’s life with the learning, training and teaching of Gracie Jiu-Jitsu. We do so with a passion that we hope Helio would take pride in.
The new year season abounds with sale items that pray upon our resolution sentiment – and the primary sale item is exercise equipment. Just look through the store adds (Kohls, Sports Authority, Dicks Sporting Goods, Sears, Target, Walmart) and “great deals” are being offered on machines, bands, balls, “perfect” this and “power” that. But the only thing all these items have in common are:
1.They feature beautiful models.
2.The average buyer will use them for less than one month.
3.The models didn’t get into great shape using the equipment that will be used by the buyer for less than one month.
So, to “build a strong core”, “work your glutes”, do a “perfect push-up” and “power up for the new year”, bring the garbage equipment back to the store, put the money back into your bank account, and challenge yourself to simple body weight movements each day (body weight push-ups, sit-ups and squats). Add in a little self-control with respect to your diet, and you’ll achieve almost all of your fitness goals!
Fads and gimmicks are for the emotional buyer, and have nothing to do with lasting fitness. The ingredients required lasting fitness are a little bit of skill (check out any of the hundreds of CrossFit blogs and YouTube videos for information regarding how to do real push-ups, sit-ups and squats), and a LOT of self-discipline.
Now the question is, do you have self-discipline? It’s no secret that most people do not. They need a push! And if you are one of these people then use the money you’d spend on fads and gimmicks, and spend it on a legit and motivating community of athletes. There you will learn skills, develop your abilities, and help others when they choose to get involved.
So, get going, stay strong, lose the gimmicks and the excuses. Fit starts now.
People often ask me if it’s scary to get in the ring. When I tell them that I’m not afraid, I’m not always sure that they believe me. How could I find joy in putting myself in front of another person who is going to do her best to hurt me? How could hurting another person be fun? That’s a situation that’s supposed to spark fear, not be a form of enjoyment.
I think that a lot of fear comes from what you’ve experienced in life. Some of the events in my life have been truly frightening. After living through those, fighting seems easy by comparison.
When I was 18, I left my home in Morocco to escape a marriage that my mother had arranged between me and a man in his 30s. For me, it was an easy choice. I could go off in search of my own life, or I could resign myself to an existence with a man I didn’t know, I didn’t love, and a life I didn’t want…barefoot and pregnant?! Not for me. Something told me it was time to leave, so I decided to go in search of this ‘American Dream’ I’d heard so much about on the news…I didn’t know what it was, but I wanted it! So in my 18th year of life I left home.
I remember arriving in New York City and feeling a strange combination of complete freedom and absolute terror. I had no friends, spoke no English, and wasn’t sure what to do next. My skills as a teenager, barely an adult, were very limited. I was really scared, but motivated at the same time. I had heard about the ‘American Dream’ but had no idea where to find mine…
I made my way to Virginia to live with my father. After a short stay, he kicked me out when he realized that I wasn’t interested in living a strict Muslim lifestyle and marrying a man of his choice; I was suddenly homeless…again. For the next three months, through the winter, my home was a tent in a local park. I worked as a day laborer, because that’s where I could meet other people who spoke spanish. Every morning, we’d gather in front of the local 7-11 and wait for a truck to take us to that day’s job. I knew nothing about home improvement or construction, but it was either learn quickly or starve. At the end of each day, I’d go to K-Mart and buy clothes and food. I also bought a portable heater, one of the few comforts I had during this time in my life. In order to keep going, I had to continually tell myself that eventually, things would get better. I had to find that dream!
Things turned around when I met a man, who like me, spoke fluent arabic. This man was a stranger, but for some reason I found myself pouring out my life story to him. He told me he was looking for a dependable worker for his home improvement business, and after some convincing, he hired me. Eventually, I was able to earn enough money to rent a bed from a local family. I moved on to rent basements, spare rooms, living wherever I could afford a place to lay my head.
It was around that time that my boyfriend introduced me to jiu-jitsu. He had been learning a little bit, and would put me in holds that I couldn’t get out of. We both signed up for classes at Capital Jiu-Jitsu. After years in the states, I’d finally found something I did for pure enjoyment!
The gym became my second home, and my team quickly became my family. I knew nothing when I started. In fact, most students were new. We all learned together, and it was exciting for all of us to help each other learn.
I trained consistently for the next four years, except for a brief interruption when I trained as a firefighter. I worked for the local fire department for three-and-a-half years. I enjoyed the work, and the schedule allowed me to pursue a dream that I’d had in my mind since I started training: to test my skills in the ring. This, I thought, could be it, it could be what I came here for….
It was a long road to my first match. I trained for nine months, learning to fight standing up, getting my diet in order, and seriously focusing on my conditioning. During those nine months, I lost thirty pounds and brought my cardio and strength to new levels. I could out fight all the female students and out lift most of the men. I was stronger and faster than I had ever dreamed. Not many women in their early 30s can make those claims!
Before my first fight, I wasn’t scared of getting hurt. I was excited and motivated. I was driven by a sense of obligation. The last thing I wanted to do was let down my coaches and training partners, who had selflessly devoted their time to helping me prepare. My opponent – a jiu-jitsu fighter like me – had my back early in my first fight, but I stayed calm, and eventually mounted her and won by strikes in the third round. I’ve mentioned the low points in my life, but when I won that first fight, I felt so high that I didn’t fall asleep until after five the next morning. I realized when my hand was raised by that ref, this was it. This was MY American dream.
My record is now 3-0-1. I’ve been in the cage, I’ve taken the punches and I have kept coming forward. I’ve battled on the jiu-jitsu mat against men twice my size. I’ve fought fires and helped save lives. I’ve crossed the ocean, forging a new life from sweat and hard work. People say I have a strong chin; I say I have a stronger heart. Even after I’m done with fighting, I’ll still look for ways to challenge myself and see how far I can go. My entire adult life has been a challenge. I’s the only way I know how to live, finding a challenge, always in search of my dream.
***
Iman Achhal was born on January 12, 1977 in Tetuan, Morocco. She has lived in Virginia, for 13 years.
Iman currently teaches and trains full time at Capital Jiu-Jitsu.
With the overwhelming success of both Capital Jiu-Jitsu staff and students in competitive events, more and more members are approaching me with their own desire to fight. If you are considering competing in the cage, ring or on the mat, then the following article is for you.
A Fighter’s Words To Live By:
-Conditioning is Confidence
-Eat Clean – You Are What You Eat
-Train For The Worst… Hope for the Best
-Fights Are Won During Preparation… Fights Are Lost On Event Day
-If You Can’t Pull It Off In Training, You Won’t Under Pressure
-Rehearse, Rehearse, Rehearse!
-The Mind Breaks First In A Fight… Learn To Take Away Your Opponent’s Will To Fight
-Attack Your Weaknesses!
A Fighter Spends Time Developing:
-Strategy
-Tactics
-Conditioning
-The Will To Win
-Support Group (Coaches, Training Partners, Family & Friends)
A Fighter Knows The Science Of:
-Performance Dieting
-Cutting Weight While Maintaining Performance
-Performance Conditioning
-Training Cycles
-Proper Training vs Over Training
-Visualization
-Rest
The Questions of Diet & Supplements:
-Protein should be lean and varied and account for about 30% of your total caloric load. Carbohydrates should be predominantly low-glycemic and account for about 40% of your total caloric load. Fat should be predominantly monounsaturated and account for about 30% of your total caloric load. Calories intake should be set to optimum levels based on weight and training volume.
-Your foods should primarily come from vegetables, fruit, lean meats, nuts and seeds. Processed foods, starches, sugars and fatty meats should be avoided.
-Supplements are NOT the answer. Some supplements might provide a small benefit for recovery, sleep, immune system response and digestion, but these benefits are very small compared to Performance Dieting, Performance Conditioning (with Training Cycles), Visualization and Rest.
Develop Your Training Cycle
The most common training cycle for CJJ competitors is the following:
-Break a sweat 2X, 5 days a week using a 3 on, 1 off, 2 on, 1 off weekly cycle.
-Use one off day for active recovery training (light yoga, walking, etc….)
-Use one off day for complete physical and emotional rest.
-A full Micro-cycle should last between 4 and 6 weeks. The cycle should include a ramp up phase of a week or two, develop into full blown training, and end with a reduction in intensity.
-A fighter should peak on the day of their fight.
-Avoid the common pitfalls of overtraining, cutting weight in a way that equals a loss of performance, flatlining by over-recovering the week before the event, and resting too much or too little before beginning a new training cycle.
-(a Macro-cycle is a string of Micro-cycles, and for fighters at the professional level, Macro-cycles are an important consideration for career performance.)
A Fighter Knows Their Sport
Will you be on the mat in a no-gi match? Are leg locks allowed? Will it be full rules Muay Thai? Is headgear required? Is your fight MMA? What are the time limits? If you have ANY questions then research, research and research! You have no chance of winning a game you don’t fully understand.
All the above information requires prior knowledge. If you don’t understand what is a high glycemic food, what is a training cycle, what are tactics and strategy, what are signs and symptoms of over-training, then you have a LOT of work and research to do before you decide to step into the cage, ring or any other high level competition. Also, everything you do MUST EQUAL PERFORMANCE. If you are still stuck on doing bicep curls to get ready for beach week, then you have no business planning for a fight. Know your priorities, do your homework, do your legwork and then begin putting together a long-term plan for winning your chosen competitive event.
I cannot tell you how often friends, students and fans approach me and ask me what I do to stay in such good shape. It is often a very frustrating experience for me. Why? Because when I tell them my honest answer, they want a DIFFERENT answer.
Here is my honest answer to how I stay in such good shape:
1. I stay on a strict CrossFit training schedule, practice my sports (Jiu-Jitsu, Muay Thai and MMA) and eat a very healthy Zone diet.
2. I take my training seriously, but monitor over-training. I avoid an on-again/off-again mentality – and will go as far as to train around injuries.
3. I listen to my coaches.
What everyone wants to hear is that I use some special supplement, do some special secret workout, or that I was born with a high metabolism. But that is just not the case. Staying thin, strong, fast and healthy are hard work for me! Very hard work! But I make the personal sacrifices necessary to be at my best.
I think that is why people have such a hard time with my answer. People don’t really want to make sacrifices. They want it easy. They want some pill that will make them all better – or some excuse that means they don’t have to try – because it won’t matter anyway. But the true answer is that success IS hard work. I guess that is why not many people reach their goals. But how I feel is that if something is worthwhile, then it probably is not easy.
Now work hard and reach your goals. They might not be easy, but think of them as challenges. And at the very least, good challenges can be fun!
Muay Thai is one of the most devastating striking art’s to have ever been developed. Indigenous to Thailand and South East Asia, Muay Thai incorporates every limb of the human body to serve as a weapon for both offense and defense. Training Muay Thai teaches a person to effectively use their hand’s, knee’s, feet, and elbow’s to strike against an opponent while standing.
The Muay Thai low kick is an effective tool to keep your opponent at bay and a great way to break their spirit by inflicting sheer pain. Applying an effective Muay Thai low kick takes a lot of practice to accurately and consistently hit your target. The low kick targets either the inside or outside of your opponents legs just above the knee. This portion of the leg has the least amount of muscle tissue and can only withstand so many devastating blows.
If the opponent does not block/check correctly, the leg can be either broken or develop painful blood clots eliminating his or her ability to stand. If your opponent can not stand on or use the leg, then they can no longer fight.
The most important thing to remember when training the low kick is to open your hips and keep your chin protected.