Runners . . . can you hop ?

Photo credit: Lenore Edman

Photo credit: Lenore Edman

You might think you are a great hopper, but that is because you are never on the same leg hopping forward sequentially. Running is hopping off one good leg, potentially onto another that is just a little less optimal, then back onto a better leg, never fully appreciating a potential asymmetry. 

If you are not assessing your client's hop ability you might be missing some very valuable information. The trouble will be, determining what the deficit is. Telling them they merely have to hop more on the perceived-deficit side is not solving the problem. More does not equal better (unless one is referring to ice cream).

Today, we are in the podcast studio and we will briefly be talking again about the importance of assessing your client's hop ability. Do they have the skill, endurance and strength to hop well, and hop symmetrically?  After all, running is a hopping skill, it is a long jump hop forward in the sagittal plane, followed by an airborne float phase, and an abrupt landing onto the next limb, it is a long jump hop one after the other. If you cannot hop competently, you are at risk.

Skill: Do you have the skill to hop symmetrically ? When you do 15 fast hops forward do the legs feel the same side to side in terms of coordination? or is your foot all over the place "exploring for stability"? Does your knee swim inward, does your hip drift a little into the frontal plane, do you drop the swing leg pelvis ?

Endurance: Can you do it 15 -20 times or more, how about 50? After all, you are about to do a 5mile run (or more !). If you fatigue in any of the components on one leg, your hops are not the same. Get ready for compensation adaptations. So, when you feel something going "funky" wrong in a long run, what do you do? Do you stop, walk and recover or do you keep going ? Many of us are good at ignoring the "blinking check engine light". There is nothing wrong will walking for a bit and giving some fatigued tissue a little time to recover before you start into your run again. We believe many injuries could be avoided if we could get past our "mental moron" issues as runners.

Strength: can you protect the joints and planes from compromise, drift, rotation etc ?

Hopping comprises: proprio, forefoot take off and loading, ankle rocker, a competent tibialis posterior, peroneal group, and achilles-calf complex, knee flexion dampening ability, hip flexion and others . . .

you must be able to stabilize the frontal plane

you must be able to dampen rotational loads

you must be able to keep the knee sagittal

you must control the rate of pronation

you must be able to cyclically convert the foot from flexible to rigid and back again, almost immediately

Just some things to think about before your long run this weekend. We will follow up this post with a long form discussion on an upcoming podcast. We hope you will tune in.

"It is concluded that the fatiguing exercise protocol combined with single-leg hop testing was a reliable method for investigating functional performance under fatigued test conditions. Further, subjects utilized an adapted hop strategy, which employed less hip and knee flexion and generated powers for the knee and ankle joints during take-off, and less hip joint moments during landing under fatigued conditions. The large negative power values observed at the knee joint during the landing phase of the single-leg hop, during which the quadriceps muscle activates eccentrically, indicate that not only hop distance but also the ability to perform successful landings should be investigated when assessing dynamic knee function.

Single-leg hop testing following fatiguing exercise: reliability and biomechanical analysis. Scand J Med Sci Sports. 2006 Apr;16(2):111-20 Augustsson J1, Thomeé R, Lindén C, Folkesson M, Tranberg R, Karlsson J.    https://www.ncbi.nlm.nih.gov/pubmed/16533349

 

Jumping is a skill. Don't do it like this.

Jumping is a skill. Look at his right knee, i wouldnt want to be his knee. The knee is a sagittal hinge, not a lateral hinge. This is going to likely lead to a Valgus Thrust degenerative joint. Jumping is a sagittal plane skill first , master that first.
It just hurts to watch his right knee !

http://www.menshealth.com/…/best-core-and-cardio-workout-men

Jumping height seems to depend on limb position.


In this study of 12 classical female ballet dancers, jump height was tested in both turn out and in a neutral hip position. This study was essentially looking at the effects of external hip rotation turn out on lower limb kinematics. The study seemed to control for forward trunk lean, but it is unclear if this included anterior or pelvis tilt pre-posturing. After all, we know very well that anterior pelvis tilt (APT) will significantly inhibit gluteal function (go ahead, dump into APT and try to fire your glutes ! Nadda !)

Here are the study results:
"The dancers jumped lower in the TJ (turn out) than in the NJ (neutral). The knee extensor and hip abductor torques were smaller, whereas the hip external rotator torque was larger in the TJ than in the NJ. The work done by the hip joint moments in the sagittal plane was 0.28 J/(Body mass*Height) and 0.33 J/(Body mass*Height) in the TJ and NJ, respectively. The joint work done by the lower limbs were not different between the two jumps. These differences resulted from different planes in which the lower limb flexion-extension occurred, i.e. in the sagittal or frontal plane. This would prevent the forward lean of the trunk by decreasing the hip joint work in the sagittal plane and reduce the knee extensor torque in the jump."

So, when was the last time your sport allowed you to jump cleanly from the neutral hip and pelvis position? Not likely right ?! So, our rehab and our training must include non-neutral drills and skills, since that is where we live most of the time in our sporting and active lives.

Sports Biomech. 2017 Mar;16(1):87-101. doi: 10.1080/14763141.2016.1205122. Epub 2016 Jul 14.
Comparison of lower limb kinetics during vertical jumps in turnout and neutral foot positions by classical ballet dancers.

Imura A1, Iino Y1.
https://www.ncbi.nlm.nih.gov/pubmed/27418231

Toe flexor strength and ankle dorsiflexion ROM during the countermovement jump

This study looked to evaluate the relationships between peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height.

"The results showed (1) a moderate correlation between ankle dorsiflexion range of motion and countermovement jump height and (2) a high correlation between peak first toe flexor muscle strength and countermovement jump height. Peak first toe flexor muscle strength and ankle dorsiflexion range of motion are the main contributors to countermovement jump performance."

There could be variables missing here, and plenty of caveats. We should try to get the full text on this one to be fair. None the less, interesting facts to brain juggle however.
These muscles are posterior compartment muscles so it makes sense, however, when the first great toe (the hallux) is in relative flexion, the arch is easier to drop (conversely, hallux dorslflexion causes the arch to raise and keeps the ankle dorsiflexion more purely in the ankle mortise) where as, with relative toe flexion, the arch can drop, this can generate some pronation and arch splay, which can increase the "appearance" of more ankle dorsiflexion when in fact some could be from the arch drop/pronation. I wonder if the researchers are aware of this variable or if this study took it into consideration. Certainly when someone is dropping into ankle dorsiflexion ready to jump, is is easy to drop the arch. Go ahead, dry doing it with the toes down , and then with the toes up in extension, its very different in the amount of dorsiflexion you can get out of the entire arch-ankle mortise complex combined. IT is these kinds of things that can easily be over looked and skew findings.

Correlation between toe flexor strength and ankle dorsiflexion ROM during the countermovement jump

Sung Joon Yun1) 2), Moon-Hwan Kim2), Jong-Hyuck Weon3), Young Kim4), Sung-Hoon Jung5), Oh-Yun Kwon5)

Journal of Physical Therapy Science
Vol. 28 (2016) No. 8 August p. 2241-2244

link : https://www.jstage.jst.go.jp/article/jpts/28/8/28_jpts-2016-202/_article?platform=hootsuite

https://www.jstage.jst.go.jp/article/jpts/28/8/28_jpts-2016-202/_article?platform=hootsuite

More on landing mechanics.
Here is a recent article on landing mechanics. This article talks about the landing mechanics far past where I feel the first stage of vulnerability is, which is initial forefoot load, as i discuss in the video pertaining to landing from a jump or if sprinting (forefoot loading). IF landing occurs in low gear (lateral half of the forefoot), inversion risks are higher.
The medial foot tripod, high gear toe off (1st and 2nd mets) is where we should be taking off from, and landing initially upon. Anything lateral is vulnerable without the lateral column strength (lateral gastrocsoleus complex, peronei longus/brevis).
This article talks about knee flexion angles and ACL vulnerability, far after this initial loading response. The article some valid conclusions in that phase.

- Dr. Shawn Allen

Posture specific strength and landing mechanics.

http://lermagazine.com/article/posture-specific-strength-and-landing-mechanics

https://www.youtube.com/watch?v=8T9UzOaYxmo

The effect of lower extremity fatigue on shock attenuation during single-leg landing.

Thank goodness the body can compensate. Here is a perfect example of this discussed in this study.
“ … it has been shown that a fatigued muscle decreases the body’s ability to attenuate shock from running. The purpose of the study was to determine the effect of lower extremity fatigue on shock attenuation and joint mechanics during a single-leg drop landing.”
This study suggests that as one part fatigued, the joint and muscle strategies elsewhere in the limb made up for it.
“Hip and knee flexion increased and ankle plantarflexion decreased at touchdown with fatigue. Hip joint work increased and ankle work decreased.” The results suggested that the lower extremity is able to adapt to fatigue though altering kinematics at impact and redistributing work to larger proximal muscles.

The effect of lower extremity fatigue on shock attenuation during single-leg landing. Clin Biomech (Bristol, Avon). 2006 Dec;21(10):1090-7. Epub 2006 Sep 1.
Coventry E1, O'Connor KM, Hart BA, Earl JE, Ebersole KT.
http://www.ncbi.nlm.nih.gov/pubmed/16949185

Podcast 91: Gait, Vision & some truths about leg length discrepancies

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Show notes:

Gait and vision: Gaze Fixation
What’s Up With That: Birds Bob Their Heads When They Walk
http://www.wired.com/2015/01/whats-birds-bob-heads-walk/
 
Shod vs unshod
 
Short leg talk:
11 strategies to negotiate around a leg length discrepancy

From a Reader:

Dear Gait Guys, Dr. Shawn and Dr. Ivo,  I was referred to this post of yours on hip IR…http://thegaitguys.tumblr.com/post/14262793786/gait-problem-the-solitary-externally-rotated   I am impressed by the level of details of your understanding of the gait and biomechanics. Although I am still trying to understand all of your points in this post, I would like to ask you:  What if my IR is limited due to a structural issue? The acetabular retroversion of the right hip in my case. 

I.e. if I am structurally unable to rotate the hip internally.
What will happen? 
What would be a solution to the problem in that case? 

Single-leg drop landing movement strategies 6 months following first-time acute lateral ankle sprain injury - Doherty - 2014 - Scandinavian Journal of Medicine & Science in Sports
http://onlinelibrary.wiley.com/doi/10.1111/sms.12390/abstract

Hey Gait Guys,

I understand that 1st MP Joint dorsiflexion, ankle rocker, and hip extension are 3 key factors for moving in the sagittal plane from your blog and podcasts so far. I really love how you guys drill in our heads to increase anterior strength to increase posterior length to further ankle rocker. I’ve seen the shuffle gait and was curious if you had a good hip extension exercise to really activate the posterior hip extensors and increase anterior length. 

Shod landing provides enhanced energy dissipation at the knee joint relative to barefoot landing from different heights.

Its great to wear shoes if you are jumping, but not necessarily running. It is interesting that ground reactive forces were not significantly different for shod vs unshod conditions and that that knee flexion, angular velocity and power were higher for those “perceiving” that there would be more cushioning. It goes to show we are not smarter than our brain (we just think we are !).


 http://www.ncbi.nlm.nih.gov/pubmed?term=%22Yeow%20CH%22%5BAuthor%5D

Knee. 2010 Aug 24. [Epub ahead of print]

Shod landing provides enhanced energy dissipation at the knee joint relative to barefoot landing from different heights.

Yeow CHLee PVGoh JC.

Department of Orthopaedic Surgery, National University of Singapore, Singapore; Division of Bioengineering, National University of Singapore, Singapore.