i know how you feel. i did tkd for several years..then life got in the way and i injured my back and put on a ton of weight. any how i got back in to it over a year ago. and i have real issues with side kicks and piercing kicks... round house.. not much i can do bout it right now now..only thing i can think of is to work more on my legs at the gym since i know they are really weak..along with my hips.. and i plan on getting a leg stretching machine... i know those things do wonders. originally i used one all the time and could actually do the splits after some time... so that is what i am going to try for again ..when i have the cash to invest in my own stretcher. other wise i just do the best i can....

Have you tried positioning your front foot at all, so that your shoulders are turned, which will make you bring that leg over more? What i do, is if i'm doing a left leg roundhouse, i'll start with my right foot aimed in the 1-2 o'clock position and then my shoulders and legs all move together and across. The same goes for a right leg roundhouse. I'll start with my left leg aimed in the 10-11 o' clock position, and then make my turn with the shoulders and legs all in unison. See if that helps......

This makes me glad that kicks in our style are mostly waist level and below, waist, groin, knees etc. I have ZERO flexion in my hips, and they hurt by the time we're done with class if it's a kicking intense class.

I began TKD in 1985 and currently teach its kicking principles to the fighters at my current gym. The roundhouse is the hardest kick to teach to anyone who it doesnt come naturally to. (its also the kick i associate with agility and balance when assessing my fighters' mobility.) I will try to break it down to apply to you, even though i havent seen you train. you may be doing some of these things already. WARNING: since this is not live instruction, this will be a long read. im sorry. you can skip me altogether if you want.)

the reason I associate the kick with agility and balance is because, as someone mentioned, foot positions and adustments are being made during the entire technique. because of this, people who have not commited the movements to muscle memory (whether natural or learned) have too much to process to make it fluid. after its broken down, repetition is the answer. (kobe bryante shoots at least 100 jumpshots every day and his field goal average is still only like 45%) repetition repetition repetition. we've had entire classes with nothing but roundhouse drills.

so lets address the hip mobility. what others have said is true. if the lead leg foot position is not correct at the start, major adjustments must be made during the technique and that results in an awkward roundhouse. if your lead foots is facing forward (12oclock) when you start, the hips will not be "open" enough to swing the leg across. this has nothing to do with flexibilty because the foot position issue applies even if you throw a roundhose at knee level. (so lets practice the roundhouse at the knee level until you get it.)

as you begin the motions, the first thing to happen will be the lead foot (lets assume its the left foot in front, right leg in the rear) needs to take a small step from toes facing 12oclock to facing 9oclock. this should open the hips. even without a kick being thrown, bringing the right foot to the left foot is an "across" motion because your lead foot forces your hips to turn and align.

Example: start with feet together facing forward 12oclock. take a step with the left. bringing your right to your left in the next step doesnt change hip position or direction or anything, correct? you merely took a step forward and are still facing forward. thats like a front snap kick. now, start with feet together facing forward 12oclock. take a step with the left, but this time, turn it outward so it faces 9oclock when it lands. now, bringing your right foot to your left in the next step you find that your lead foot position causes you to align your hips and when the step is done you are facing left. this is like a roundhouse....

was this exercise successful? should I save my typing or am i helping even a bit?

Don't take this the wrong way, but if after 3 years you cannot do a correct roundhouse kick maybe it also has something to do with the instruction you are receiving.

Is flexiblity the issue?

First, congratulations. It is good to see such dedicated students such as you who are looking for improvement. Having owned and operated schools for years, just know that students like you are truly a gem.

Now I want you to know that you have everything you need to succeed. The key to anything is breaking it down to its simplest components.

I imagine you can perform a correct front snap kick. It has four parts (knee up, extending the leg top of the foot flat with toes up, retracting it back, and setting it down. A round house is a front snap kick in transition.

When I teach this kick, I teach it with imagery. Imagine your shin or top of the foot is a baseball bat in which you will use to hit your target. That mental image of a person swinging horizontally is the picture I want you to have in your head.

Now the components of the kick...

1) stand in a ready stance, both feet forward like you are walking on a rail road track.
2) bring kicking leg up to waist height, pivot on the ball of your foot of standing leg where foot is pointing outward 30-60 degrees, allowing the knee to bend slightly
3) roll the kicking knee over like you were trying to lay the inside of your knee on top of a table
4) extend the kick focusing to kick the target with the shin or top of the foot
5) retract the kick
6) set it back down


You can work up to this and do it more Japanese style by starting in back stance/arrow stance and raise the knee up, pivoting on forward foot, turn the knee over, and extend through the kick

One of the methods to help people to get passed the mental block and to find the proper form for themselves is to place a folding chair in slightly in front and to the side and forcing them to raise the leg up and gliding over the chair towards the target. All of these methods have worked.

However, for speed techniques, being able to throw a round house from a relaxed standing position is much to your advantage. Namely being able to bring the knee up vertically in front of your opponent and throw the kick is less likely to be blocked, is a lot less motion (telegraphing), and allows quicker transition to follow up strikes.

Let me know if this helps or if you need anything else and best of luck to you.

start practicing kicking at knee shin height and slowly work your way up.

This is excellent advice. I am older than most of you and my body doesn't stretch the same as it used to. My Sensei has instructed me to imagine a long table, pick your knee up to your chest, try to point your kicking hip to the floor and "swipe" imaginary stuff off of the table. (This creates the pivot others talk about).
He has us do it very slow until he is convinced we have the proper form. He doesn't want us to worry about height or how hard we kick until we understand what works for us. I am short waisted and long legged so I struggled with this since my center of balance is different than most of the others in our class. One day, it just happened and now it is one of my favorite kicks! Keep trying!