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