Glad you liked it. Any questions don’t hesitate to asked!

Glad you liked it! Any questions don’t hesitate to ask!

Quick follow up:

You wrote that the psoas is a flexor and EXTERNAL rotator of the hip – I misread that. Two points then:

1. If the hip internally rotates with the cross over gait than this would put the psoas under tension. This would then allow it to produce more force. Much like hip extension allows it to stretch and then release its energy.

2. I thought the psoas was a hip INTERNAL rotator. This is from Neuman’s article in 2010 on the Kinesiology of the hip muscles. Its moment arm is quite small (thats why i think it is pretty debatable). Not sure if you think this influences your theory or not. In some ways it might actually help it (via the length tension route) but it would lessen or insight into viewing hip internal rotation as an indicator of less psoas contribution to hip flexion.

Fun stuff!

Greg

Thanks Jeff,

I think these discussions are important and interesting. I hope you don’t find it too Monday morning quarterbacking. I know no better way than to learn something than to discuss and question our own biases. Many call this Grad school.

While I like to get into the details academically I take the approach that the body is so incredibly complex that WE actually need to be much simpler in our interventions. Your posture response showed that. You don’t rely on the posture you probably place greater value in how they move. I’ve just taken this a little further in that I put very little value in the static assessment and mostly look at their running. I’m not even sure any simplistic tests of function (single leg squat – although I do it) really correlate with the kinematics that occur during running.

Your other two examples (limited ankle DF = limited hip extension) and the Jeptoo Valgus gait possibly causing a weakened Psoas because the psoas must shorten due to hip internal rotation) are interesting. You use observed kinematics to visualize where the psoas might be on its length tension relationship and then extrapolate how its force production might decrease.

So with those two examples its the “altered” positioning of the thigh during stance that lead to a conclusion of changes in active/passive hip torque.

Do you have any other kinematic flaws during running that you look for that might compromise psoas function?

Email if easier. Would love to continue the conversation. (I’m serious about testing it if you like: greglehmanphysio@gmail.com)

John-I look forward to reading your blog. Sounds like you are doing some great work, look forward to learning from you!

Jeff Moreno

http://www.informrunning.com/2013/12/12/runner-specific-gluteal-activation-the-crossed-extensor-reflex/

http://www.informrunning.com/2013/11/07/fishing-rods-and-bad-dogs/

Glad to read of a similar approach

John Foster

In a perfect world we would know all of the forces involved and the muscle activation patterns of each runner that we treat. Maybe that will happen someday, but not possible now, and the tech needed to be able to model forces internally is prohibitively expensive for most small clinics (and probably a lot of larger ones). I think we can infer some information about forces by looking at kinematics based on the lit available, and I certainly think there is value in a kinematic assessment in a clinical setting.

I happen to disagree with some of his comments and would be interested in what others treating runners think. However, if you are a running geek like myself he has a great website. Check it out!

Hi Jeff,

Nice to meet you! I read your article with interest. In general, I believe that the (much) older research does not provide a clear assessment of the underlying mechanisms of running, primarily for two reasons:

1) You cannot make a running injury or strategy assessment from kinematics alone. There are many possible muscle recruitment strategies that can make up a given running motion because the human musculoskeletal system is overactuated (i.e. many more muscles than joints). We really need more work to determine what the real objectives of human running are. In other words, what are the low level criteria that we seek to achieve that makes us run the way we run. You may be interested in some recent work I presented this year on this topic: http://www.timzone.net/conferences/ISB2013_PredictiveRunning.pdf and the accompanying video http://www.timzone.net/conferences/ISB2013_PredictiveRunning.mp4

2) You cannot probe the kinetics of the musculoskeletal system. Given that it is not possible to non-invasively measure internal muscle or joint forces in the body during a dynamic activity, we must rely on computer models and simulations to generate predictions. Although our models aren’t perfect (and in general, not patient specific), we can still nevertheless probe internal metrics that can give us much more insight to how muscle groups synergize to coordinate movement. In a study last year (http://www.timzone.net/papers/Muscular_strategy_shift_in_human_running__dependence_of_running_speed_on_hip_and_ankle_muscle_performance.pdf), we found that the coordination strategies of running appear to be more complex than the eye suggests. Specifically, not only are the stance and swing phases of a leg highly correlated, but the forces in the ipsilateral leg significantly and simultaneously affect the dynamics of the contralateral leg (via the dynamic coupling effect). Although it may appear counter-intuitive at first glance, it actually makes a lot of sense because forces from a single muscle are transmitted through the joints along the entire body, and preparing one leg for some given part of the stride may require the other leg to be in a specific pose — thus requiring action to be taken by the contrilateral leg for the ipsilateral leg to function properly. I agree with your suggestion to “look globally” because everything is related to everything else and forces in the muscles must be generated at the precise times — this is why it’s so difficult to create walking robots — walking and running is more complicated than we think!

Of course, you are welcome to browse through all the articles on my website, http://www.timzone.net, including some hamstring injury papers during the late swing phase of sprint running, which you may find interesting. They all use musculoskeletal modeling and simulation to answer questions that cannot be answered from kinematic analysis alone. Feel free to post these comments on a blog if you so desire.

Cheers,
Tim

Greg-thank you for posting and bringing to my attention the great work that Anthony Schache and Tim Dorn are doing right now in the world of gait. Tim is currently at Stanford University which is only a 45 minute drive from Santa Cruz, Ca where I live. Small World!

As you know running is extremely complex and requires highly coordinated patterns of movement with specific timing. Understanding human development and normal gait helps to give us a baseline understanding in these complex patterns of movement, which allows us to look a patients/clients with greater specificity. Unfortunately, most clinicians and coaches don’t have access to 3D motion capture software and treadmills with force plates. Therefore, due to the confines of insurance, financial resources, and time we use our understanding of normal movement and the neuro-musculoskeletal system to hypothesize “Why”, for example, a runner is developing 5 stress Fx’s in the right tibia in a two year span (NCAA Division I collegiate runner of mine).

Let me try and answer your questions:

1. I don’t think you can look at a runner and see their “active and passive” contributions to joint torque. I don’t see this as a valid assessment tool.

I agree with you that it is impossible to know objectively what specific active and passive contributions to joint torque are during specific phases of gait. However, if I see runner that purely runs on his/her forefoot with and early heel off prior to mid-stance, I can hypothesize that this may result in poor ipsilateral hip extension due to the dominance of the plantar flexors (pseudo hip/gluts) and contralateral hip flexion during swing. I am also going to question their ability to generate torque actively and passively at their hip. I will also ask myself if this is increasing the joint torque at their ankle, possibly explaining their history of achilles tendinopathy, MTSS, metatarsalgia etc… As you know, we use our understanding of current research, and what we see in the clinic, through our assessment, to bolster our clinical reasoning process.

3. I don’t think we have any valid method of looking at someone run and saying that their psoas is not contributing to hip flexion and it’s their TFL or RecFem. You just can’t look at kinematics and surmise what the muscles are doing to create that movement. If you have some validated ways I would love to change my mind.

The psoas muscle and all the other muscles that synergistically produce hip flexion are always going to contribute to forward motion of the leg. I am definitely not saying that the psoas muscle is completely off. However, there can be very defined muscular imbalances that are produced due to poor coordination of movement and timing resulting from environment, habit, motor control, poor proprioceptive awareness etc… that can carry over to the walking/running gait. These muscular imbalances can create dominances in certain muscles leading to a crossover gait for example. In a crossover gait the hip adducts during swing phase which can facilitate the hip flexors that internally rotate the femur (TFL) leading to excess hip adduction and internal rotation during stance. Now, as a result of this hip adduction and internal rotation dominance the psoas muscle, which is a hip flexor and external rotator, is going to have a less than optimal mechanical advantage at this point to help coordinate triple flexion.

2. I wish that we would stop getting hung up on these antiquated views of Kendall and Sahrmann “faulty” posture. Static posture has a poor link to dynamic function and is certainly not related to pain.

Static posture alone will tell you nothing. But static and dynamic posture, along with a detailed assessment gives the clinician a window into how the athlete’s brain represents movement and their ability to control and overcome gravity. You as a clinician know that we are always looking for patterns, whether optimal/suboptimal, that contribute to muscular imbalances. If someone is standing with a posterior COM, knees hyper-extended, hypertonicity in the quads, femoral medial rotation, with tibial lateral rotation, and has poorly defined gluts (“flat butt syndrome/gluteal amnesia”), I am going to start developing clinical hypotheses that I need to rule in/out during my assessment. Do I stop there and start treating, absolutely not, but it is a part of my clinical reasoning process. I think you would agree that the neuromuscular system wants to produce movement in the most efficient way possible. With that said, that does not always mean that it is biomechanically efficient. The human body will compromise quality of movement in order to conserve energy. This can be a big problem for an athlete if not addressed.
Now back to our assessment, once this same athlete starts to walk they begin to express that same quad dominant pattern with excess femoral medial rotation and poor loading response knee flexion with a limited ankle rocker. They single leg squat, hop, and jump with this same pattern. Why would their brain want to express any other pattern in an activity that is 2.5 to 2.8x body wt on one leg (running)? You have seen this same athlete running with excess hip adduction uncompensated pelvic drop, femoral medial rotation, and tibial lateral rotation (sign of the toes). This runner is extremely compliant to gravity and demonstrates poor muscular stiffness globally. Does giving this runner glut and core exercises alone change their muscular imbalances, absolutely not? I want this athlete just to start controlling gravity in all areas of life, let alone running. I want this athlete to understand what it is like to walk correctly and control and overcome gravity at 1.5x body weight. I want this athlete to be able to coordinate basic fundamental patterns of movement easily and then transfer that understanding to their running gait. This is the art/science of the clinician. Do we need to improve on our understanding of all aspects of human movement, absolutely! People like yourself, Tim Dorn, and countless other researchers, clinicians, and coaches need to keep up this discussion to further our understanding of the running athlete.
Thank you for your great work!!

Jeff Moreno

James- Thank you for the reference!