This post was originally posted in the Kenpo Forum. Dr. Dave gave permission for it to be shared. I would like to post this for discussion and analyze how we do our kicks. Are they that dangerous? Is there good technique that could help to minimize hip wear? Could some older kickers chime in and give us younger practicioners some advice?
We rented a video-flouroscopy (VF) unit a couple years ago, and taped the open and closed chain joints in motion during the performance of basics. VF is ongoing X-ray...instead of a snapshot of a millisecod in time, it's watching TV. It's a several minute x-ray, used in physical medicine to either giude injection procedures, or to evaluate the movement of jonits for abnormal soft tissue findings. For example, someone beig taped in VF walking on a treadmill with a ruptured ACL on the right...the right knee will look very different, with an unatural "hitch" in it during gait, compared to the left. We were curious about some very specific things, relative to some concerns about biomechanics that had come about during a lecture on the effects of cumulative trauma sports injuries (i.e., guys who run wrong, swing their bat wrong, serve a tennis ball wrong, etc.). So we taped the hips and knees during specific types of kicks, the lumbar spine and thoraco-lumbar junction during lower extremity basics (kicks, small foot maneuvers, etc.), the shoulder during specific movements with the potential to create wear and tear for martial arts enthusiasts (reverse punches, upward blocks delivered to the side vs front, and backnuckles delivered to the side vs to the front). We also trained the VF on the cervical spine at the shoulders and base of skull while subjects from kenpo, kajukenbo, TKD, and boxing performed 5-10 repetitions of moves. We taped it, then analyzed the heck outta the tapes. I wish I had them still; I'm sure someone could make a PC friendly file of them, and we could post them here for all to see. But, to the point.
Front kicks are about the only kick that can biomechanically be done safely to chest height. Side kicks and roundhouses -- kicks delivered to the side of the body -- should not be delivered above the level of the belt; ideally, no higher than your own bladder (anatomically just slightly lower than the articulations of the hip joint). Doing so either 1) places more stress on intra-articular and peri-articular tissues than they were meant to have, or 2) requires accomodation and compensations at other places in the body (i.e., knees, spine at lumbo-pelvic junction, others) which create a whole set of injuries on their own.
We are designed to step high and reach forward with a foot, then pull the ground we gained to us (relatively)...the gluteus max, hamstrings, sacrospinalis, contralateral adductors, and some buncha other muscles come into maximum play with actions similar to walking up a hill, or stairs, or reaching far forward in a sprinting stride, then recoiling the leg back to the body to take the ground you covered in the forward stretch phase of the running gait. A front kick is akin to placing your foot on the hillside up in front of your thorax, then changing your mind about going uphill and bringing it back down again. For someone who takes many high steps covering lots of ground (i,.e., hikers, etc.), the flexibility is there to allow this motion to normalize within the complexities of the hip joint and pelvic nutation/counter-nutation rhythems.
Aside from the un-natural movements employed in martial arts, when, in the course of hunting and gathering, do we whip our leg out to the side, higher than our head? It is not in the natural repetoire of human motion. We can force it, but the price is compression of tissues that do not like to be compressed.
Dig out Snells, Grays, Rohen & Yokuchi, or some other basic anatomy text (I copied some pics from the web, but can't figure how to place them). Look not only at the complex structure of the hip joint itself -- giving up flexibility for stability, and holding that stability in place through a twisted set of very tough ligaments and connective tissue structures -- but also at the relationships of the femoral head in the acetabulum, particularly in relationship to the fovea capitus (little hole in the ball part of the ball and socket hip joint).
There is a ligament & accompanying blood vessel that feeds the hip, and communicates through this tiny hole in the head of the femur, within the joint capsule of the hip itself. The fibrous capsule of the hip is twisted to maintain an optimal strength-tension curve relationship, providing stability to the hip joint while facing the correct parts of the femoral head to the articulating surface of the acetabulum (the ball in the socket). Superficial and deep muscles that cross the hip joint support it further in specific planes of motion. There are hip flexors (muscles that move the thigh forward or pick the knee up towards the sky out in front of you), hip adductors and abductors (some that sway the leg away from you at the hip, and some that sway it back to you); extensors (butt muscles that lift your heel rearwards); and external and internal rotators (allowing you to turn your toes in, or out).
"Pure" movements will consist of one or more of these motions, preferably not combining more than 2 sets of motion. I.e., hip flexion with external rotation (iliopsoas, with assistance from some of the deep 6 and piriformis, plus either gracilis or sart...can't recall specifically, been too long and am too lazy to fetch a reference)...the motion used in picking your leg up, and stepping forward with it towards a front twist. There are no natural combinations for picking your leg up and out to the side, straightening it, then elevating it to chest level or above. It's made possible by the assistance of abdominal and lumbar lateral flexors (i.e., quadratus lumborum, others), and by a quick contraction of major external rotators (gluteus medius), complemented with a counter contraction of hip flexors and thigh extensors (psoas, sartorios, quads, etc.). This combination of possible, but unnatural, motions essentially forces the femoral head to engage in an infero-lateral glide within the acetabulum. Not possible as a true movement, so hip flexion takes over and, at the last moment, pulls the ball rearward in the socket to allow for the forward relative movement of the kicking leg (in the roundhouse), or the snapped-forward movement of the hip joint when a side kick is delivered to 8:30 or 3:30, since the hip jonit wil not allow for straight lateral elevation to a true relative 3:00 or 9:00 at high altitudes.
Muscular anatomy is what the thing is. Biomechanics is what it does. The muscles listed at the top of the chart are for internal or external rotation...obturator niternus and externus, superior and inferior gamellus, quadratus femoris, gluteus minimus, and piriformis. The closest muscle to lateral elevation is the tensor fascia latae...only about the size of a silver dollar, and clearly not designed to carry the full weight of the limb into lateral elevation.
On VF, there is a violent snapping of the hip in the joint, starting on one path, then being suddenly and forcefully yanked in another. This places undue stress on a number of structures:
1. The fibrous hip capsule
2. The articular hyaline cartilage of the hip joint (a slick, shiny surface joints are supposed to glide over)
3. The artery & ligament as they communicate through the fovea capitalis
4. The sacroiliac ligaments on both the ipsilateral and contralateral sides relative to the kick, but more on the ipsilateral side
5. The lumbar discs and zygoapophyseal joint capsules of the bottom three spinal articulations.
I guarantee that, after only one year of high kicking in any of the planes other than a front kick, and even there higher than your own sternum, you will start having cracks in the articular surfaces of the hip joint; stress injuries (sprains & strains) to the fibrous hip capsule & assisting musculature, annular fissures to the bottom 2-3 lumbar discs, facet joint damage to at least the bottom three articulations of the low back, and tissue degradation within the hip joint itself secondary to compromised blood supply. Additionally, I have seen the before and after x-rays of the hips of guys who have spent about a year of training in kicking arts (most specifically, TKD & Thai, as well as "match-style" kenpo). There is an early degenerative change visible on plain film x-ray called a "sub-chondral cyst". Basically, this is where a rough load was placed on the joint, and a tiny fracture occurred in the plates between the different levels of cartilage & bone, causing some hyaline cartilage -- the smooth, glassy stuff -- to get pushed under pressure to the area just beneath the outer shell of main bone; like a piece of carpet getting pushed under itself. On x-ray, it looks like intermittent bubbles along the articulating surfaces of the hip joint. It is an early sign of advanced degeneration. A bad thing. It means the biomechanics of the hip have been compromised, and with every step, the wear and tear on that joint is greater than it would have been without the cysts. On film, it's like seeing 45 year old hips in 25 year old men. All from kicking high.
It ain't just a theory, folks. Many years ago, some fringe nutjob made a connection between smoking, and lung cancer. It started with the simple observation that smokers got it a lot more than non-smokers. Then for years the tobacco companies denied it, while thoracic, cardio and lung surgeons knew better. Kicking high in any plane is a bad idea. Here's the early warnings; time will show more of this surfacing as the effects of age are exacerbated by the effects of poor kicking habits. But we'll never get the funding the medical community got for cancer research, so we need to listen to subtler signals and signs. Tess feels it in her cage, because the pelvis and hips can't get there without enlistnig the back for help. People feel it in their knees, because with the stability of the hip joint compromised, somebody has to hold your ridiculously imbalanced butts up off the floor. (incidently, also causes knee damage, by placing increased stress on the menisci in the knees via semi-membranosis, plantaris, and other muscles that go from hip to knee and foot/ankle/foreleg to knee). The hip joint and low back joints on the side of the kicknig leg take a beating, while the knee of the supporting leg takes one.
In short, if you value the idea of orthopedic surgery at a younger-than-necessary age, keep on high-kickin. In TKD? switch your focus from kicking high, to kicking hard at a lower elevation. Especially if you're a woman. The cards are already stacked against you for hip and bone health problems; why add to it? And if you're a man? Well...weren't all the pioneers and seniors mentioned earlier men? No one is immune to the effects of crappy, unwise biomechanics. It may look good and feel great when you do it, but it's a bad idea. I walk like an old man with a load in his pants because of the damage I did to my own hips and low back, training to kick high, fast & pretty. I used to be able to throw 100's of high repetitions in training, and could smack plenty-o-folk in the head while sparring without tipping my head back (the classic compromise made in TKD to help get the leg higher). With a 2nd ni TKD, I spent lots of time training jump spin kicks. I used to watch Gil Kim, from Hwarang-Do, do his...sucker would graze the cieling tiles with near vertical spreads. I decided I wanted to be able to do that, and actually got close. Now, I can barely throw 10 proper kicks knee-high before my back starts screaming at me. Then, it takes about 3 days of advil megadosing before I can walk in some semblence of normalcy. I gotta find some old photos or video so Doc doesn't think I'm just fibbin about having been able to kick, once.
Preventive medicine = Is it bad for you? Then stop it.
Regards,
Dr. Dave
