October 05, 2016

Who Rules -- The glutes or the quads? Well, it is complicated.

October 05, 2016/ The Gait Guys

We have often talked about how important it is to be able to achieve terminal hip extension for an athlete, and arguably for everyone. This means one must have strength of the glutes into that terminal range so one can actually achieve the range of motion and access it functionally. If one does not, then extension movements may occur in the lumbar spine via some anterior pelvic tilt. However, one must not dismiss that upright posture needs sufficient quadriceps strength as well -- meaning, hip extension and knee extension get us to an upright posture and make locomotion possible. If we make the hip flexors or quadriceps tight, due to weakness of the lower abdominals or glutes, we get anterior pelvic posturing and less hip extension (these are admittedly very rough principles, we all know it is far more complex that this). What I am saying is that there is an interaction amongst groups of muscles, functional patterns of engagement, recruitment and whatnot.

One must clearly realize how much knee and hip motions are coupled and work with and off of eachother. If we bend over in a squatting type motion, we are in hip flexion and knee flexion. When we stand, hip and knee extension. These guys play off of eachother. One must consider these issues when movements are more advanced and loading and loading rates are magnified, such as in squatting type lifting.

A few weeks ago Bret Contreras in conjunction with Strength and Conditioning Research put out an article by Yamashita , yes, a 1988 article. "EMG activities in mono- and bi-articular thigh muscles in combined hip and knee extension." What this article looked at was what happened during isolated hip extension and isolated knee extension, and more importantly, what happened to the forces when both joints loaded simultaneously, paired in generating extension at the hip and knee, as in a squat.

This article suggested that when hip and knee extension forces are generated in conjunction, the knee extensors are more activated than if the same force was generated in isolation. What this seemed to suggest is that during the extension phase of a squat, it is easy for the quad thigh muscles (rectus femoris, vastus medialis in this study) to to try and rule the movement, from an activation perspective -- the hip extensors (g. max and semimembranosus) take second seat. We have talked many times about the dangers of this principle when we frequently say "the glutes should be in charge of the hip, not the quads, when the quads try to apply dominant control of the hip motion, trouble may ensue." Admittedly, this may not be entirely true and it is very loosely stated, but the principle has some sound value when it is approached from how we intend it to be heard, that many athletes do not have sufficient glute strength, hip extension range of motion, and poor control of pelvic neutral. So, they dump into the quads because as we see here in this study, they are very appropriately positioned to help synergistically drive the positioning for, and activity of, hip extension motor pattern production. Is this why we see small buttocks and large quadriceps in distance runners, and the opposite in sprinters ? We think so, but we need to dive deeper into the research to prove or disprove it, but the principles seem to make sense.
This is why I like to initially drive my glute and hip extension work with my clients in a more knee flexed position, such as supine bridges. I cannot say it better than Bret Contreras did when he reviewed this article,

"So exercises that involve less knee extension (glute bridges, hip thrusts, deadlifts, pull throughs and back extensions) will tend to produce much greater hip muscle activation than those that involve more knee extension (squats, lunges, and leg presses), although there are always other factors involved of course!".

If you are not following Bret's and Strength & Conditioning Research's work, you are missing out, They are thorough and insightful, they do their homework, learn from them.
We clearly need to dive into some newer research on this topic, we will see if we can squeeze out the time.

- Dr. Shawn Allen, the other "gait guy"

Here is an embedded code for the beautiful slide that accompanied Strength and Conditioning Research's summary of the study. If you cannot find it above in this post, goto their Facebook page and scroll to Sept 22nd, 2016. You will find it beautifully laid out there. Beautiful job S&CR!

January 04, 2016 January 04, 2016/ The Gait Guys

Falling hard; Using supination to stop the drop.

“One thing, affects all things. One change necessitates global change. The more you know, the more you will see (and understand). The more you know, see and understand, the more responsible you will and should feel to get it right and the more global your approach should become. If your head does not spin at times with all the issues that need to be juggled, you are likely not seeing all the issues you should be seeing.” -Dr. Allen (from an upcoming CME course)

This is a case that has been looked at before but today with new video. This is a client with a known anatomic short leg on the right (sock-less foot) from a diseased right hip joint.

In this video, it is clear to see the subconscious brain attempting to lengthen the right leg by right foot strike laterally (in supination) in an attempt to keep the arch and talus as high as possible. Supination should raise the arch and thus the resting height of the talus, which will functionally lengthen the leg. This is great for the early stance phase of gait and help to normalize pelvis symmetry, however, it will certainly result in (as seen in this video) a sudden late stance phase pronation event as they move over to the medial foot for toe off. Pronation will occur abruptly and excessively, which can have its own set of biomechanical compensations all the way up the chain, from metatarsal stress responses and plantar fasciitis to hip rotational pathologies. It will also result in a sudden plummet downwards back into the anatomic short leg as the functional lengthening strategy is aborted out of necessity to move forward.

This is a case where use of a full length sole lift is imperative at all times. The closer you get to normalizing the functional length, the less you need to worry about controlling pronation with a controlling orthotic (controlling rate and extent of arch drop in many cases). Do not use a heel lift only in these cases, you can see this client is already rushing quickly into forefoot loading from the issues at hand, the last thing you should be doing is plantarflexing the foot-ankle and helping them get to the forefoot even faster ! This will cause toe hammering and gripping and set the client up for further risk to fat pat displacement, abnormal metatarsal loading, challenges to the lumbricals as well as imbalances in the harmony of the long and short flexors and extensors (ie. hammer toes).

How much do you lift ? Be patient, go little by little. Give time for adaptation. Gauge the amount on improved function, not trying to match the right and the left precisely, after all the two hips are not the same to begin with. So go with cleaner function over choosing matching equal leg lengths. Give time for compensatory adaptation, it is going to take time.

Finally, do not forget that these types of clients will always need therapy and retraining of normal ankle rocker and hip extension mechanics as well as lumbopelvic stability (because they will be most likely be dumping into anterior pelvic tilt and knee flexion during the sudden forefoot loading in the late midstance phase of gait). So ramp up those lower abdominals (especially on the right) !

Oh, and do not forget that left arm swing will be all distorted since it pairs with this right limp challenge. Leave those therapeutic issues to the end, they will not change until they see more equal functional leg lengths. This is why we say never (ok, almost never) retrain arm swing until you know you have two closely symmetrical lower limbs. Otherwise you will be teaching them to compensate on an already faulty motor compensation. Remember, to get proper anti-phasic gait, or better put, to slow the tendency towards spinal protective phasic gait, you need the pelvic and shoulder “girdles” to cooperate. When you get it right, opposite arm and leg will swing together in same pendulum direction, and this will be matched and set up by an antiphasic gait.

One last thing, rushing to the right forefoot will force an early departure off that right limb during gait, which will have to be caught by the left quad to dampen the premature load on the left. They will also likely have a left frontal plane pelvis drift which will also have to be addressed at some point or concurrently. This could set up a cross over gait in some folks, so watch for that as well.

“One thing, affects all things. One change necessitates global change. The more you know, the more you will see (and understand). The more you know, see and understand, the more responsible you will and should feel to get it right and the more global your approach should become. If your head does not spin at times with all the issues that need to be juggled, you are likely not seeing all the issues you should be seeing.” -Dr. Allen (from an upcoming CME course)

Shawn Allen, one of the gait guys.