On deep squatting and hip flexor flexibility: Aims: A) To establish that deep squats (“Below parallel”) with correct technique serve to isometrically stretch (And thus simultaneously strengthen) the hip flexor muscles, therefore increasing the flexion range of motion of the hip joint (And thus the angle of the femur) independently of the position of the lumbar spine (Which affects the angle of the sacrum, and therefore of the entire pelvic complex), and simultaneously reducing the strain put on the lower back by overly tight hip flexors. B) To establish how correct squatting technique can be used to facilitate such an isometric stretching, using an approach based on awareness and control of joint angles. Part 1: The hip flexor muscles. (http://www.exrx.net/Muscles/Iliopsoas.html) (http://en.wikipedia.org/wiki/Hip_flexors) (http://www.exrx.net/Articulations/Hip.html#anchor845056) The hip flexor muscles, for the purpose of this text specifically referring to the psoas major, psoas minor and iliacus muscles, sometimes collectively called the iliopsoas, cause, as their name indicates, what is known as hip flexion, that is, the reduction of the angle between the femur and the lumbar spine. However, where most muscles only cross one joint, the psoas component of the hip flexor muscle complex originates on the lumbar spine, bypassing the pelvis entirely, therefore the psoas cross (And thus affect) multiple joints. With maximum shortening, the iliopsoas thus causes lumbar flexion. This has postural ramifications when the complex is constantly shortened, causing what is known as anterior pelvic tilt (When the bottom of the pelvis is tilted backwards, and the top is tilted forwards). When the relevant muscles are hypertonic (Contracted strongly even at rest), or have been weakened to a point where full extension cannot safely be maintained due to not being capable of exerting enough force to return to a neutral position without tearing (Causing it to tighten so as not to be extended beyond a safe range), the adoption of an erect posture with the ribcage balanced above the hips results in a constant pull on both the lumbar vertebrae and the femur, in turn resulting in the hips becoming constantly flexed to accommodate the shorter muscle length, and the lumbar spine to hyperextend as the upper body is brought back to preserve balance: This in turn causes the abdominal musculature to shift away from its natural position, leading to weakening in the long term, which in turn leads to further postural issues due to the resulting muscular imbalances. It should be rather clear that keeping the hip flexors healthy is an integral part of the maintenance process of good posture, although the prevalence of sitting posture and the abandonment of natural squatting motions in the modern world make it difficult, since it means that the hip flexors spend excessive amounts of time at rest in a shortened position, which leads them to weaken by under-use, increasing the tendency to suffer from the above problems. Part 2: The squat. The squat as a motion is part of the natural movement patterns of the human body, and is nowadays still conserved in numerous cultures in lieu of the sitting posture commonly employed in “the west”, as can be seen in the following images: In some of these cultures, even the toilets are built directly into the ground, requiring the user to squat in order to use them, resulting in the squatting motion being completely ingrained into their common movement patterns. As can be seen, squatting involves the flexing of all three main leg joints (Hip joint, knee, ankle), so that the body remains balanced between the feet even as it is lowered as much as physically possible. Due to the wide range of motion of the squat, it has been adopted as a strength training exercise, particularly due to the relatively powerful contractions used to push oneself back up to a standing posture (Another aspect missing from modern sitting, both in the reduced range of motion, and in the disproportionate amount of time spent in it without standing). Two details worth pointing out regarding the full squat: A- Leaning forwards: As one descends, it is necessary to lean forwards in order to keep one’s weight centered between one’s feet. This is a function of the relative distribution of one’s weight, the range of motion of the joints involved, and of the pull of one’s muscles at any given position, and can be artificially affected by the addition of external weight, as it is done in weightlifting (Which in turn affects muscle activation, as the muscle pull required to center the weight shifts alongside the distribution of the total weight) and by the modification of one’s base of support (Stance width, relative height of heels and toes, degree of internal or external rotation of the legs, etc). B- Tilting the hips: It is noticeable in the above images that the ones squatting have what is called a posterior pelvic tilt (Naturally, this is the opposite of the previously described anterior tilt). This is the result of full contraction of the iliopsoas, and is a requirement if one is to squat as low as physically possible. In order to get here, the hip flexors contract to flex the hips, then extend at a certain point in the range of motion if the lumbar spine is kept extended, and then contract again, tucking the tailbone. This sketch illustrates this: Do note that the more one leans forwards, the more flexion one is likely to cause in the spine as the hip joints reach their flexion limit, therefore creating posterior pelvic tilt, and that controlling this tilt relies on methods related to point A. Also note that such a tilt is undesirable in weighted squatting, since it can cause one to fall backwards, or put undue stress on the lower back, therefore when training with heavy weights, proper technique and posture is of utmost importance, as is not going too low if heavy tilting is observed. Now to the crux of the matter: using the squat to enable the iliopsoas to exert more strength at greater levels of extension, therefore preventing or rehabilitating anterior pelvic tilt (As well as helping weightlifters develop deeper and safer heavy squats). Squatting can be done with weights or without weights; having good bodyweight squat technique indicates adequate leg and hip health for everyday life, but weights will always give better strength development, and if done well, result in even healthier legs and hips. Additionally, the use of external weights, such as barbells, dumbbells, weight plates, kettlebells, or even random objects will shift the distribution of total weight, and can help bypass certain mobility issues by providing that extra force needed to prevent one from falling if the body can’t balance itself through a full squat. First of all, experiment and find a foot position that is comfortable for squatting. The “traditional” squatting position has the feet approximately shoulder width apart (That meaning that your heels are directly below each shoulder), and pointed out between approximately 5 and 30 degrees from being parallel. Some people recommend doing a few small, relaxed hops in place, and using the position in which you land as a base from which to squat. To test if the stance is adequate, find a chair, stool or other raised surface that is just above knee-height relative to you, stand with the backs of your thighs touching the edge, move away from it a few inches, and bend hips, knees and ankles at the same time until you’re sitting on it (Even if you end up dropping into it, the important thing here, specifically, is to keep those three joints aligned so that they don’t get injured). See http://www.exrx.net/WeightExercises/GluteusMaximus/BBBoxSquat.html and http://stronglifts.com/build-explosive-strength-how-to-perform-box-squats/ for instructions on how to do it as a strength exercise with a barbell on your shoulders, although the difference between that and doing them unweighted is minimal, being essentially an increase in the strength required, and a shift in weight distribution affecting the forwards leaning. Once you have identified an appropriate squatting stance, it’s time to look at your squatting posture. Having one or two mirrors and/or a camera is always useful, but by no means vital. The first thing you should do regarding this, after positioning your feet correctly, is to simply relax and let your legs bend at the three joints. The objective is to have all three joints bend simultaneously (Until a certain point, they will also bend at exactly the same angles. Do not go past this point yet) and have your weight drop completely vertically. Make note of how your spine reacts; it should be kept completely straight as if you were standing up, the only flexion occurring from the hips downwards. After this, you will start trying to control your lumbar tilt, always aiming to maintain lumbopelvic extension (http://www.exrx.net/Articulations/Spine.html#anchor165667) and trying to avoid hunching your shoulders (In fact, push your chest out, it’ll make your squatting easier). Upon being satisfied with your posture, it’s time to start going lower. If you can’t do a full squat already, start with very high box squats, and if you can’t lower yourself into a box squat, sit on the edge of the “box”, extend your back completely (Emphasize the arch of the lower back), lean forwards until your weight is on your heels, and stand up slowly, without using your hands for support (Additionally, try not to curl your toes, as that causes over-activation of the calf muscles and throws off your balance). Repeat a few times per day for a few days until you can do a full repetition of a box squat, then work from there. It is worth noting for those with inflexible ankles that elevating the heel a few centimeters can help, although excessive elevation can strain the knees if the squat is not full (This text focuses on hip mobility, so allows for heel elevation, but it doesn’t focus on a full “ass-to-grass” squat either, so elevate your heels at your own risk, and listen to your body). For those who can do squats or box squats, you will progressively go lower and lower along your existing squatting range of motion, at a slow speed and maintaining strict lumbar extension, until the point where your hip flexors start extending again (You’ll feel them tighten, and if you go lower, your hips will tuck under). If you can’t get to this point in a controlled motion, continue performing partial range of motion squats or box squats until your strength and endurance have built up enough for you do it. Once this point is reached, the objective is to first be able to hold this position while maintaining spinal posture (One minute should be sufficient), then start mobilizing up and down the range of motion, to develop some endurance past that point, and make sure that you won’t cramp, and finally to employ isometric tension to stretch and strengthen the hip flexors. If you perform your squats (Box or otherwise) with added weight, simply holding the position and ever so slightly forcing yourself to go deeper (For safety, never more than a centimeter or so per training session, or the closest approximation thereof than you can estimate while doing it, and always VERY slowly) while maintaining the lumbopelvic extension (This is the single most important point here. Don’t lose this!). If you simply do unweighted squats, or wish for an added challenge with weighted squats (With which you should be extremely careful), you will have to do a contract-relax stretch, that is, one in which you exert a constant contraction of the muscle to be stretched, until it is fatigued, and then relax it and immediately (But without rushing) increase the range of motion. In the case of the squat, you squat down to the aforementioned limit, and then tense your lower body and abdominal musculature (You need to be careful with this if you have high blood pressure. Make sure to breathe deep if you do, to avoid any dangerous spikes). You will hold this tension until your muscles start to fatigue (Hopefully your hip flexors will do this before the others, else you will need extra strength and endurance), upon which you will take a deep inhalation, exhale suddenly as if sighing or blowing out a candle, and as you exhale you will relax, lower yourself a small distance, and once again extend your lumbar spine. If done correctly, you should now be lower than you were before, with good posture. If you are unable to extend your lumbar spine, rise slowly until you can (Which should still be lower than where you did the isometric stretch). You will repeat this a few times (The amount depending on your muscular endurance. Don’t kill yourself but don’t slack off either), then stand back up and rest. Since isometric stretching has a heavy strength element, it should be treated as a strength training exercise, meaning that you should take at least one rest day before you attempt it again. Vary the length and intensity of the contractions, the distance you move in between them, how you breathe in between contractions, etc, according to what you find comfortable. Always remember that the objective is not to go deep, per se, but rather to stretch and strengthen the hip flexors, so the actual depth of the squat is secondary to proper posture. That said, a healthy person should be able to squat to what is known as “below parallel” in strength training circles, which means that the crease of the hip joint (Or what would be the top of your thigh if you were standing up) is below the crease of your knee, which in turn should be enough mobility to have a healthy ass-to-grass squat with the hip tucked, but it is always worth being able to keep going lower in order to keep the iliopsoas as healthy as possible in order to preserve your lower back.
This is a really interesting and useful article. However, it uses a lot of technical language and sentence structure. It would be even more useful if you cut down on the technical language and structure. This would mean you having to spend more time explaining things and being more explicit, but it would then be available to a wider audience, especially those who don't deal in technical biomechanical language on an everyday basis. Like most martial artists who don't have a physio, PE, or sports science degree!
