Do quarter squats transfer best to sprinting?

We have always said that exercises are specific as to the type of exercise (isometric, isotonic, isokinetic) as well as the speed of exercise. And this backs that up, with a surprise:

Unexpectedly, QUARTER produced superior gains in both vertical jump height and 40-yard sprint running times, compared with both HALF and FULL. give it a read, especially the vertical jump section..

https://www.strengthandconditioningresearch.com/promotions/quarter-squats-transfer-sprinting/

How much “dip” in the coronal plane is in your single leg squat?

“In conclusion, the Single-Leg Squat is a reliable tool to identify patients that would need to improve their hip and trunk muscle weakness and dysfunction (by strengthening and neuromuscular coordination retraining). ”

Crossley et al., Am J Sports Med 39 (2011) 866 – 873.

Performance on the single-leg squat task indicates hip abductor muscle function. – Anatomy &…

Clinical assessment of performance on the single-leg squat task is a reliable tool that may be used to identify people with hip muscle dysfunction.ANATOMY-PHYSIOTHERAPY.COM

GOT GLUTE MEDS?

Want to strengthen that gluteus medius we were talking about Monday? Have you considered walking lunges with dumbbells? These seem to activate the side contralateral to a better extent than split squats.

We wonder if you get the same effect with a medicine ball. Anyone out there have some data or experience with that?

Stastny P1, Lehnert M, Zaatar Zaki AM, Svoboda Z, Xaverova Z. DOES THE DUMBBELL CARRYING POSITION CHANGE THE MUSCLE ACTIVITY DURING SPLIT SQUATS AND WALKING LUNGES? J Strength Cond Res. 2015 May 8. [Epub ahead of print]

A look at the Lunge. Are you ready to take the lunge?

Another one of our favorite exercises. Unfortunately, all too often it is executed improperly. Watch carefully, as we cover many points in detail.

Remember the mantra; Skill, Endurance, Strength. In that order. Not every individual is ready for every exercise you may give them. Be sure to build an adequate foundation before proceeding ti the next level.

This excerpt is taken from our video series, available for download here.

The Gait Guys. Join the movement and spread the word. .

Lombard’s Paradox: A unique look at the cooperation of the quadriceps and hamstrings

Lombard’s Paradox

 In searching our personal archives for neat stuff we came across an oldie but a goodie. We posted this one on the blog for the first time in July 2011 so it was time to revisit it here on the blogs “Rerun Fridays”. This is one to certainly make your head spin. We do not even know where this came from and how much was our original material and how much was someone  else’s.  If you can find the reference we would love to give it credit.  We do now that we added some stuff to this but we don’t even know what parts were ours !  Regardless, there is a brain twister here worth juggling in your heads.  Lets start with this thought……..

When you are sitting the rectus femoris (a quad muscle) is “theoretically” shortened because the hip is in flexion. It crosses the bent knee in the front at it blends with the patellar tendon, thus it is “theoretically” lengthened at the knee.  When we stand up, the hip extends and the knee extends, making the R. Femoris “theoretically” lengthen at the hip and shorten at the knee.  This, it bodes the question…….did the R. Femoris even change length at all ? And the hamstrings kind of go through the same phenomenon. It is part of the  uniqueness of “two joint” muscles.   Now, onto Lombard’s paradox with more in depth thought on this topic.

Warren Plimpton Lombard (1855-1939) sought to explain why the quadriceps and hamstring muscles contracted simultaneously during the sit-to-stand motion.  He noted that the rectus femoris and the hamstrings are antagonistic, and this coactivation is known as Lombard’s paradox.

The paradox is classically explained by noting the relative moment arms of the hamstrings and rectus femoris at either the hip or the knee, and their effects on the magnitude of the moments produced by either muscle group at each of the two joints.

By virtue of the fact that muscles cannot develop different amounts of force in their different parts, the paradox develops.  The hamstrings cannot selectively extend the hip without imparting an equal force at the knee. Thus, the only way for hip extension and knee extension to occur simultaneously in the act of standing (or eccentrically in the act of sitting) is for the net moment to be an extensor moment at both the hip and knee joints. Lombard suggested three necessary conditions for such paradoxical co-contraction:

  • the lever arm of the muscle must be greater at its extensor end
  • a two-joint muscle must exist with opposite function
  • the muscle must have sufficient leverage so as to use the passive tendon properties of the other muscle

In 1989, Felix Zajac & co-workers pointed out that the role of muscles, particularly two-joint muscles, was much more complex than has traditionally been assumed. For example, in certain situations, the gastrocnemius could act as a knee extensor. It is clear now that the direction in which a joint is accelerated depends on the dynamic state of all body segments, making it difficult to predict the effect of an individual muscle contraction without extensive and accurate biomechanical models (Zajac et al, 2003).

 In fact, back to the gastrocnemius another 2+ joint muscle (crosses knee, mortise and subtalar joints), we all typically think of it as a “push off” muscle.  It causes the heel to rise and accelerates push off in gait and running. But, when the foot is fixed on the ground the insertion is more stable and thus the contraction, because the origin is above the posterior joint line, can pull the femoral condyles into a posterior shear vector. It thus, like the hamstrings, needs to be adequately trained in a ACL or post-operative ACL, deficient knee to help reduce the anterior shear of normal joint loading. It is vital to note, that when ankle rocker is less than 90  degrees (less than 90 degrees of ankle dorsiflexion is available), knee hyperextension is a viable strategy to progress forward in the sagittal plane.  But in this scenarios, the posterior shear capabilites of the gastrocnemius are brought to the front of the line as a frequent strategy.  And not a good one for the menisci we should mention.

Andrews J G (1982)  On the relationship between resultant joint torques and muscular activity  Med Sci Sports Exerc  14: 361-367.

Andrews J G (1985)  A general method for determining the functional role of a muscle  J Biomech Eng  107: 348-353.

Bobbert MF, van Soest AJ (2000) Two-joint muscles offer the solution – but what was the problem? Motor Control 4: 48-52 & 97-116.

Gregor, R.J., Cavanagh, P.R., & LaFortune, M. (1985). Knee flexor moments during propulsion in cycling—a creative solution to Lombard’s Paradox. Journal of Biomechanics, 18, 307-16 .

Ingen-Schenau GJv (1989) From rotation to translation: constraints on multi-joint movement and the unique action of bi-articular muscles. Hum. Mov. Sci. 8:301-37.

Lombard, W.P., & Abbott, F.M. (1907). The mechanical effects produced by the contraction of individual muscles of the thigh of the frog. American Journal of Physiology, 20, 1-60.

Mansour J M & Pereira J M (1987)  Quantitative functional anatomy of the lower limb with application to human gait  J Biomech  20: 51-58.

Park S, Krebs DE, Mann RW (1999) Hip muscle co-contraction: evidence from concurrent in vivo pressure measurement and force estimation. Gait & Posture 10: 211-222.

Rasch, P.J., & Burke, R.K. (1978). Kinesiology and applied anatomy. (6th ed.). Philadelphia: Lea & Febiger.

Visser JJ, Hoogkamer JE, Bobbert MF & Huijing PA (1990) Length and Moment Arm of Human Leg Muscles as a Function of Knee and Hip Angles. Eur. J Appl Physiol 61: 453-460.

Zajac FE & Gordon MF (1989) Determining muscle’s force and action in multi-articular movement  Exerc Sport Sci Revs  17: 187-230.

Zajac FE, Neptune RR, Kautz SA (2003) Biomechanics and muscle coordination of human walking – Part II: Lessons from
dynamical simulations and clinical implications, Gait & Posure 17 (1): 1-17.

Lombard’s Paradox: A unique look at the cooperation of the quadriceps and hamstrings

Lombard’s Paradox

 In searching our personal archives for neat stuff we came across an oldie but a goodie. We posted this one on the blog for the first time in July 2011 so it was time to revisit it here on the blogs “Rerun Fridays”. This is one to certainly make your head spin. We do not even know where this came from and how much was our original material and how much was someone  else’s.  If you can find the reference we would love to give it credit.  We do now that we added some stuff to this but we don’t even know what parts were ours !  Regardless, there is a brain twister here worth juggling in your heads.  Lets start with this thought……..

When you are sitting the rectus femoris (a quad muscle) is “theoretically” shortened because the hip is in flexion. It crosses the bent knee in the front at it blends with the patellar tendon, thus it is “theoretically” lengthened at the knee.  When we stand up, the hip extends and the knee extends, making the R. Femoris “theoretically” lengthen at the hip and shorten at the knee.  This, it bodes the question…….did the R. Femoris even change length at all ? And the hamstrings kind of go through the same phenomenon. It is part of the  uniqueness of “two joint” muscles.   Now, onto Lombard’s paradox with more in depth thought on this topic.

Warren Plimpton Lombard (1855-1939) sought to explain why the quadriceps and hamstring muscles contracted simultaneously during the sit-to-stand motion.  He noted that the rectus femoris and the hamstrings are antagonistic, and this coactivation is known as Lombard’s paradox.

The paradox is classically explained by noting the relative moment arms of the hamstrings and rectus femoris at either the hip or the knee, and their effects on the magnitude of the moments produced by either muscle group at each of the two joints.

By virtue of the fact that muscles cannot develop different amounts of force in their different parts, the paradox develops.  The hamstrings cannot selectively extend the hip without imparting an equal force at the knee. Thus, the only way for hip extension and knee extension to occur simultaneously in the act of standing (or eccentrically in the act of sitting) is for the net moment to be an extensor moment at both the hip and knee joints. Lombard suggested three necessary conditions for such paradoxical co-contraction:

  • the lever arm of the muscle must be greater at its extensor end
  • a two-joint muscle must exist with opposite function
  • the muscle must have sufficient leverage so as to use the passive tendon properties of the other muscle

In 1989, Felix Zajac & co-workers pointed out that the role of muscles, particularly two-joint muscles, was much more complex than has traditionally been assumed. For example, in certain situations, the gastrocnemius could act as a knee extensor. It is clear now that the direction in which a joint is accelerated depends on the dynamic state of all body segments, making it difficult to predict the effect of an individual muscle contraction without extensive and accurate biomechanical models (Zajac et al, 2003).

 In fact, back to the gastrocnemius another 2+ joint muscle (crosses knee, mortise and subtalar joints), we all typically think of it as a “push off” muscle.  It causes the heel to rise and accelerates push off in gait and running. But, when the foot is fixed on the ground the insertion is more stable and thus the contraction, because the origin is above the posterior joint line, can pull the femoral condyles into a posterior shear vector. It thus, like the hamstrings, needs to be adequately trained in a ACL or post-operative ACL, deficient knee to help reduce the anterior shear of normal joint loading. It is vital to note, that when ankle rocker is less than 90  degrees (less than 90 degrees of ankle dorsiflexion is available), knee hyperextension is a viable strategy to progress forward in the sagittal plane.  But in this scenarios, the posterior shear capabilites of the gastrocnemius are brought to the front of the line as a frequent strategy.  And not a good one for the menisci we should mention.

Andrews J G (1982)  On the relationship between resultant joint torques and muscular activity  Med Sci Sports Exerc  14: 361-367.

Andrews J G (1985)  A general method for determining the functional role of a muscle  J Biomech Eng  107: 348-353.

Bobbert MF, van Soest AJ (2000) Two-joint muscles offer the solution – but what was the problem? Motor Control 4: 48-52 & 97-116.

Gregor, R.J., Cavanagh, P.R., & LaFortune, M. (1985). Knee flexor moments during propulsion in cycling—a creative solution to Lombard’s Paradox. Journal of Biomechanics, 18, 307-16 .

Ingen-Schenau GJv (1989) From rotation to translation: constraints on multi-joint movement and the unique action of bi-articular muscles. Hum. Mov. Sci. 8:301-37.

Lombard, W.P., & Abbott, F.M. (1907). The mechanical effects produced by the contraction of individual muscles of the thigh of the frog. American Journal of Physiology, 20, 1-60.

Mansour J M & Pereira J M (1987)  Quantitative functional anatomy of the lower limb with application to human gait  J Biomech  20: 51-58.

Park S, Krebs DE, Mann RW (1999) Hip muscle co-contraction: evidence from concurrent in vivo pressure measurement and force estimation. Gait & Posture 10: 211-222.

Rasch, P.J., & Burke, R.K. (1978). Kinesiology and applied anatomy. (6th ed.). Philadelphia: Lea & Febiger.

Visser JJ, Hoogkamer JE, Bobbert MF & Huijing PA (1990) Length and Moment Arm of Human Leg Muscles as a Function of Knee and Hip Angles. Eur. J Appl Physiol 61: 453-460.

Zajac FE & Gordon MF (1989) Determining muscle’s force and action in multi-articular movement  Exerc Sport Sci Revs  17: 187-230.

Zajac FE, Neptune RR, Kautz SA (2003) Biomechanics and muscle coordination of human walking – Part II: Lessons from
dynamical simulations and clinical implications, Gait & Posure 17 (1): 1-17.

Policing Gait on the Web

There is some decent information here but we do have some issues with this video. We were asked on our Facebook PAGE to talk about our thoughts on this piece.  We are not trying to criticize anyone, merely helping to keep the information accurate on the web:

1. They are promoting external rotation of the limb into the ground. They refer to this as “screwing” (as they put it) the foot into the ground. The issues here are that the foot supinates when you do this and when you do this too far you weight bear on the lateral foot and disengage the medial foot tripod. They do refer to limits on this but we need to heighten the awareness here. Someone with a forefoot valgus will go to far most likely, and someone with a forefoot varus will disengage the medial tripod quickly.  Most people will also disengage the FHB (flexor hallucis brevis) quickly during this “screwing” technique.  Furthermore, people can also become too dependent on their glutes to hold the “screwed” or supinated position and this is not a safe and reasonable way to support the limb and pelvic posturing. We see this as a very detrimental strategy when sustained PPT (Posterior Pelvic Tilt) is maintained during gait and stance.  There needs to be help from the lower abdominals and adductors as well.   Their “20%” torque is a nice mention and may help many to keep this moderate but this is really dependent on foot type and tibial torsion issues which are not discussed here. As always, not everything fixes everyone, and some things go against an admirable intention.  No digs against these nice fellas, we are just stating what we feel are critical facts not discussed. We watched part 2 and 3 in the hopes of hearing about these issues above, but they were not discussed. We wanted to comment on the videos but they have disabled the comments on youtube.

2. This posturing promotes knee hyperextension which is never good. Go ahead, try it yourself.  You cannot employ a whole lot of this external screwing during gait without changing the knee biomechanics into the hyperextension direction.  It is another reason we mention a caveat here.  If you try it, just pay close attention to what you are doing. You may try to get around the hyperextenion by dropping the pelvis anterior, disengaging your abdominals and changing hip and low back function. 

3. Merely doing what they propose here does not necessarily ramp up the intrinsic muscles of the feet (4:00 mark).  They can remain silent in this maneuver.  Keeping the toes pressed might be more productive to this end.

We watched part 2 and 3 of their Rebuilding the Foot youtube videos and frankly they just scare us a little (go ahead have a look yourself) so we will not comment on anything there. Although we strongly do not advise many of their recommendations in either part 2 or 3 for our clients you may find some stuff you like here … . . heck, who are we to say what you will be willing to try !

To each his own. We give these guys mad props for putting themselves on the net and trying to share their info.  It takes guts to put your stuff on the web, we hope they will enable the comments section so productive dialogues can ensue there in the future.

Shawn and Ivo

Is Your Foot Tripod Stable Enough to Walk or Run without Injury or Problem ?

The all to common case of the Wobbling Tripod.

Note the music we have chosen today. We tried to match the rate of the dancing tibialis anterior tendon to the tempo of the song, just for fun of course. Well, actually, for neurological reasons as well, as with a steady tempo or beat, your nervous system can learn better. Why do you think we teach kids songs to learn (or you can’t get the theme from the “Jetsons” out of your head).

This is a great video. This client has an obvious problem stabilizing the foot tripod during single leg stance as seen here.  There is also evidence of long term tripod problems by the degree of redness and size (although difficult to see on this plane of view) of the medial metatarsophalangeal (MTP) joint (the MPJ or big knuckle joint) just proximal to the big toe.  This is the area of the METatarsal head, the medial aspect of the foot tripod.

As this client moves slowly from stance into a mild single leg squat knee bend the challenges to the foot’s stability, the tripod, become obvious.  Stability is under duress. There is much frontal plane “Checking” or shifting and the tibial and body mass is rocking back and forth on a microscopic level as evidenced by the dancing tibialis tendon at the ankle level.  The medial foot tripod is loading and unloading multiple times a second. 

Is it any shock to you that this person has chronic foot problems which are exacerbated by running ?  Every time this foot hits the ground the foot is trying to find stability. The medial tripod fails and the big knuckle joint (the 1st MPJ or big toe joint) is enlarging from inflammation and early cartilage wear and decay, not to mention the knee falling medially as well!  Hallux limitus (turf toe) is subclinical at this time, but it is on the menu for a later date. A dorsal crown of osteophytes (the turf toe ridge on the top of the foot) is developing steadily, soon to block out the range necessary for adequate toe off in this client.  And that means a limitation in  hip extension sometime down the road (and premature heel rise……. did you read Wednesday’s blog post on that topic ?).

*addendum:

Take the time to develop the skill. We ask our clients to work on standing with the toes up to find a clean tripod and do some shallow squats working on holding the tripod quietly. Be sure your glutes are in charge. Then, again using the toes pressed flat but be sure the tripod is still valid, esp the medial tripod. No toe curling/hammering. Keep that glute on. Move the swing leg forward during a squat, and then behind you during a squat (mimicing early and late midstance phases of gait/running). This will help your brain realize when it needs this stability and it will also act to press you off balance and will make the foot check and challenge. Do this until you feel the foot fatigue on the bottom. Then Stop. Repeat later. If the medial tripod collapses, the knee will drop inwards and excess pronation is inevitable. We modified this with our prescription of the “100 ups”…..combine the two !

Shawn and Ivo … .  comfortably numb.

Once you have been to the Dark Side of the Moon  (and hopefully you didn’t have any Brain Damage) you will know it well and know what to expect when you return again.  Meaning, when you have seen these issues over and over again, hopefully in your daily work if not regularly here at The Gait Guys, you will quickly know what things to assess and look for in your athletes.  And you might just turn into a Pink Floyd fan at the same time, or at least crave some Figgy Pudding (but you have to eat yer’ meat! How can you have any pudding if you don’t eat  yer’ meat?).

Gait Parameter: Ankle Rocker during the Squat as a predictor for Shin Splints.

Here is a brief video we shot in our clinic. One of the primary assessments we do with all clients is a basic squat. No a “potty squat” were the tibia remains vertical and the hips press backwards, just a basic squat where the knees come forward.  We do this with toes down and toes up.

We shot this video so that we could have some visual to talk about a few things.

1.  Why toes up ?  You have read it here before on our blog.  Raising the toes is done by use of the log and short toe extensor muscles (Extensor digitorum longus and brevis, EDL, EDB and of the hallux extensors EHL, EHB).  When we activate the extensors the toes dorsiflex around the metatarsals and the toes elevate. This activates the windlass mechanism.  This mechanism tightens the plantar fascia thus shortening the distance between the metatarsal heads and the heel. Thus, the arch is  driven up.  This is why we harp on gaining toe extensor strength in flat footed and hyperpronators.  Go ahead, stand up, raise your toes and feel the arch lift. It is a solid biomechanical phenomenon. 

So, why do the squat with the toes up ?

Because when the foot is weaker than it should be a squat can allow the arch to drop too much during the down-squat.  If the arch drops the foot could pronate more than necessary. This can drive subtalar joint motion which can fake out the true squat determination and the true determination of available ankle rocker.  The client will be able to get deeper into the squat but for assessment purposes this will be a fake out.  We want to know  true available functional range at the ankle mortise joint (tibial talar joint). With the toes up, the arch is maximized and cannot drop unless the toes drop. As you will see in this video, you can thus see the true ankle rocker in this client is barely sufficient however it is likely enough (100-110 degrees) for normal gait in the sagittal plane. 

What if when they do this there is little if any rocker, less than this guy?

Then to get more (100-110, ie. 10-20 degrees past vertical) they will have to compensate.  We talk about the strategies in this old video of ours (LINK HERE).  One of the best ways to compensate is to pronate through the arch more than normal.  This will drop the arch height and carry the tibia forward enough to allow for forward motion. Sadly, this increased pronation can do alot of things.  One is to carry the knee medially and this can create patellar tracking issues or IT band tightness, to name just a few. 

So, what is our point today ?

  1. You need to make sure your assessments are telling you what you need them to tell you.
  2. Sufficient toe extensor strength and range is critical in the gait cycle to ensure sufficient ankle rocker occurs at the tibial-talar joint and not somewhere else you do not want it ( a compensation).  Any strength you put into a client who has insufficient true ankle rocker is strength into a compensation pattern.  Can you say heightened eventual injury risk ?
  3. Ability to find the foot tripod is a skill. It needs to be developed in a simple skill like we show here and then  the sensation can be carried forward into gait and running.
  4. A forefoot varus or forefoot valgus (please read our foot type blog posts over the past 3 weeks) can impair the foot tripod and thus the true ankle rocker.
  5. Make sure the knees hinges straight forward in this ankle rocker-squat test. If it is not a forward bend you must consider foot pronation excess, tibial torsion, hip version or torison, or simply the weak foot issues we are talking about here today.
  6. This is a form of homework for our clients, just want you see above in the video. We add layers to this as the gain strength. But that is a topic for another day.

This is a huge predictor and problem in chronic shin splints ? You bet ya it is ! It may be the main missed deficit we see in shin splints (both anterior and posterior shin splints).  There is lots more to this topic, but we will stop here for today. 

Shawn and Ivo…….. you have to know what you are seeing. And as Johnny Nash once said in his song

I can see clearly now, the rain is gone,
I can see all obstacles in my way
Gone are the dark clouds that had me blind
It’s gonna be a bright (bright), bright (bright)
Sun-Shiny day now that i understand ankle rockers better.”

🙂