Leg Stiffness

Griff · Mar 26, 2010

Simon Spooner said: ↑

Med Sci Sports Exerc. 1987 Apr;19(2):148-56.
Running-related injury prevention through barefoot adaptations.
Robbins SE, Hanna AM.

A number of reports indicate an extremely low running-related injury frequency in barefoot populations in contrast to reports about shod populations. It is hypothesized that the adaptations which produce shock absorption, an inherent consequence of barefoot activity and a mechanism responsible for the low injury frequency in unshod populations, are related to deflection of the medial longitudinal arch of the foot on loading. It is also hypothesized that the known inability of this arch of the shod foot to deflect without failure (foot rigidity) is responsible for the high injury frequency in shod populations. To evaluate these hypotheses, 17 recreational runners were analyzed to study the adaptive pattern of the medial longitudinal arch of the foot due to increased barefoot weight-bearing activity. Changes occurred in the medial longitudinal arch which allowed deflection of this arch on loading which substantiated the hypotheses. Other evidence suggests that sensory feedback largely from the glabrous epithelium of the foot is the element of barefoot activity which induced these adaptations. The sensory insulation inherent in the modern running shoe appears responsible for the high injury frequency associated with running. The injuries are considered "pseudo-neuropathic" in nature.
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In addition these also look interesting:

ROBBINS, S. E. and G. J. GOUW. (1991) Athletic footwear: unsafe due to perceptual illusions. Med. Sci. Sports Exerc., Vol. 23, No. 2, pp. 217-224.

Modern athletic footwear provides remarkable plantar comfort when walking, running, or jumping. However, when injurious plantar loads elicit negligible perceived plantar discomfort, a perceptual illusion is created whereby perceived impact is lower than actual impact, which results in inadequate impact-moderating behavior and consequent injury. The objective of this study was to examine how plantar tactile (mechanical) events affect perceived plantar discomfort. Also, we evaluated the feasibility of a footwear safety standard we propose, which requires elimination of the above illusion. Twenty subjects gave numerical estimates of plantar discomfort produced by simulated locomotion (concurrent vertical (0.1-0.7 kg[middle dot]cm-2) and horizontal (0.1-0.9 kg[middle dot]cm-2) plantar loads), with the foot supported by either a smooth rigid surface or a rigid surface with 2 mm high rigid irregularities. Vertical or horizontal load alone evoked no discomfort (P > 0.05), whereas together, discomfort emanated from loads as low as 0.4 kg[middle dot]cm-2. Irregularities heightened discomfort by a factor of 1.89. This suggests that the proposed safety standard is feasible, since compliance could be achieved simply by adding surface irregularities to insoles and by other changes that heighten localized plantar loads. However, until this standard is adhered to, it might be more appropriate to classify athletic footwear as "safety hazards'' rather than "protective devices''.
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ROBBINS, S. E., G. J. GOUW, and A. M. HANNA. (1989) Running-related injury prevention through innate impact-moderating behavior. Med. Sci. Sports Exerc, Vol. 21, No. 2, pp. 130-139.

The purpose of these experiments was to test the Robbins and Hanna hypothesis, which relates differences in discomfort from localized deformation at certain positions on the plantar surface to protective behavior (intrinsic foot shock absorption). A penetrometer was used to quantify the relations between localized load and pain and between load and depth of deformation. The magnitude of load required to elicit pain varied significantly (P < 0.005) in relation to position on the plantar surface. With a load of 9 kg and a 10 mm spherical end on the penetrometer, 6% of the sample reported pain at the heelpad, 32% at the distal first digit, and 66% at the first metatarsal-phalangeal joint. This pattern was predicted by the Robbins and Hanna thesis. Two deformation patterns were observed which were best explained by deformation constraint by tight trabecular tethering of the epithelial membrane at the heelpad and distal first digit and unrestricted deformation due to loose trabecular tethering of the epithelial membrane at the first metatarsal-phalangeal joint. These data provide insight into how, when barefoot, the plantar surface resists perforation yet provides protection to local bony structures. These data further support the notion that plantar sensory feedback plays a central role in safe and effective locomotion.
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I can't get any of these - I've emailed Bruce Williams to see if he can - he has helped me out with articles from this journal on more than one occassion.

One question - does anyone know Robbins and Gouw personally? What is their background? Are they barefoot runners?

mike weber · Mar 26, 2010

I Google Gouw and got this got, I found nothing on Robbins

http://users.encs.concordia.ca/~gouw/gouw.html

mike weber · Mar 26, 2010

Age seems to be a factor in leg stiffness as well, well walking down stairs.

Simon Spooner · Mar 26, 2010

Ian said: ↑

In addition these also look interesting:

I can't get any of these - I've emailed Bruce Williams to see if he can - he has helped me out with articles from this journal on more than one occassion.

One question - does anyone know Robbins and Gouw personally? What is their background? Are they barefoot runners?
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Ian,
http://reporter-archive.mcgill.ca/Rep/r3111/robbins.html
Robbins-Gouw hypothesis. Not sure if this has ever had it's own thread? Basically something like too much cushioning in shoes = strike the ground harder due to the "perceptual illusion" and "masking" of sensory input.

Griff · Mar 26, 2010

Thanks Simon. I've read of the Robbins-Gouw hypothesis in passing, and I guess this was why I asked the question regarding their background/agenda. Every article I read from them is about trainers (and is usually negative) - wondered if there was a story under pinning it all. It seems from the link you sent that Robbins is quite impartial which is refreshing.

I can't remember it ever having had its own thread either.

Simon Spooner · Mar 26, 2010

Ian said: ↑

It seems from the link you sent that Robbins is quite impartial which is refreshing.
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Ian,
None of us is impartial. We all carry an agenda, whether we like it or not. Which is one of the reasons we try to eliminate bias by "blinding" during research studies.

Griff · Mar 26, 2010

Simon Spooner said: ↑

Ian,
None of us is impartial. We all carry an agenda, whether we like it or not. Which is one of the reasons we try to eliminate bias by "blinding" during research studies.
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You are of course right. Research methods 101 I guess. Sorry bad wording on my part there - I suppose what I meant was that he isn't linked to a 'barefoot running shoe' or similar.

Simon Spooner · Mar 26, 2010

Ian said: ↑

You are of course right. Research methods 101 I guess. Sorry bad wording on my part there - I suppose what I meant was that he isn't linked to a 'barefoot running shoe' or similar.
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I know what you mean, he wasn't working for a shoe company and he was publishing this stuff before the barefoot agenda took off.

BTW, a patient of mine saw a barefoot runner in Plymouth today- that's the first report I've had- and I've been asking.

mike weber · Mar 31, 2010

I was reading Kevins article in Podiatry Today on MTSS.

http://www.podiatrytoday.com/current-concepts-in-treating-medial-tibial-stress-syndrome

1 Sentance from the below quote taken from the paper popped out to me in relation to leg stiffness.

After making the diagnosis of MTSS, one should instruct the patient to apply ice to the medial tibia for 20 minutes twice daily. Also tell patients to reduce running activities, run on softer surfaces and wear appropriate anti-pronation shoes. At the initial visit, modify shoe insoles or over-the-counter orthoses with adhesive felt padding at the medial heel, medial arch and medial forefoot to simulate the mechanical effects of a custom foot orthosis. Custom foot orthoses are recommended for the vast majority of these individuals unless their symptoms are mild and have resolved quickly with the aforementioned initial therapeutic measures.
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Davis et al Increased leg stiffness related to tibia stress fracture.

softer ground will increase leg stiffness .

so by getting the patient to run on softer ground are we increasing the leg stiffness of that patient during running on softer ground?

With a patient with MTSS through increased bending moments will increased knee flexion related to a decreased leg stiffness reduce these tibia bending moments ?

So I´ve thought about these type questions and come up with this.

I´ve made a leg stiffness scale.

decreased leg stiffness 5 -4-3-2-1-ZOOLS-1-2-3-4-5 increased leg stiffness.

If we have a patient with increased leg stiffness scale 1 they may have more chance to reduce their leg stiffness thru increased knee flexion opperate in their ZOOLS, maybe adjusting the ground surface to harder may cause this to happen. Some with increased leg stiffness 5 may not be able adjust the leg stiffness enough and softer ground maybe the better approach.

This would not be the only part of treatment clearly, but what do you think of my reasoning ?

Simon Spooner · Mar 31, 2010

m weber said: ↑

Davis et al Increased leg stiffness related to tibia stress fracture.

softer ground will increase leg stiffness .

so by getting the patient to run on softer ground are we increasing the leg stiffness of that patient during running on softer ground?
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Mike, lets say we "know" that tibial stress fracture is caused by too greater leg stiffness. To have got to a pathological situation, the CNS control of leg stiffness must have failed to maintain the leg stiffness within the non-pathological range. Therefore, if we got the runner to run on harder surfaces we are making the assumption that the system which has previously failed, can now work to reduce leg stiffness. It may or may not. MTSS syndrome is interesting, is it a bone injury or a soft tissue injury?

m weber said: ↑

With a patient with MTSS through increased bending moments will increased knee flexion related to a decreased leg stiffness reduce these tibia bending moments ?
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Potentially.

m weber said: ↑

So I´ve thought about these type questions and come up with this.

I´ve made a leg stiffness scale.

decreased leg stiffness 5 -4-3-2-1-ZOOLS-1-2-3-4-5 increased leg stiffness.

If we have a patient with increased leg stiffness scale 1 they may have more chance to reduce their leg stiffness thru increased knee flexion opperate in their ZOOLS, maybe adjusting the ground surface to harder may cause this to happen. Some with increased leg stiffness 5 may not be able adjust the leg stiffness enough and softer ground maybe the better approach.

This would not be the only part of treatment clearly, but what do you think of my reasoning ?
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If leg stiffness is an aetiology in the condition and if the surface stiffness variation creates significant enough changes in leg stiffness, then the reasoning above seems a good idea.

mike weber · Mar 31, 2010

Simon Spooner said: ↑

Mike, lets say we "know" that tibial stress fracture is caused by too greater leg stiffness. To have got to a pathological situation, the CNS control of leg stiffness must have failed to maintain the leg stiffness within the non-pathological range. Therefore, if we got the runner to run on harder surfaces we are making the assumption that the system which has previously failed, can now work to reduce leg stiffness. It may or may not. MTSS syndrome is interesting, is it a bone injury or a soft tissue injury?

.
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So then it also comes back to the factors which contribute to a persons ability to regulate leg stiffness , such as fatigue, Reduced ROM, poor QOM, muscle strength, genetics as well.

Therefore, if we got the runner to run on harder surfaces we are making the assumption that the system which has previously failed, can now work to reduce leg stiffness.
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This is something that I had not really considered , I´ll bounce that around for awhile, nice.

mike weber · Apr 3, 2010

I watched the video on the barefoot thread and the discussion between Ian and Simon.

Do you 2 or anyone else know of any research on strike patterns shod and unshod, Ie the person ff strikes unshod- reduced leg stiffness as Ian discussed, now the person is made to FF strike in shoes what is leg stiffness when compaired to barefoot? ( I might have forgotted a paper already discussed)

There was that paper about the change of the lever arms of the foot when shod listed earlier, I´m just going over a few things while doing some renovations over easter, who said men can´t do 2 things at once.

Ps Hope everyone is having a good Easter

NewsBot · Sep 9, 2010

Leg and joint stiffness in human hopping
S. Kuitunen, K. Ogiso, P. V. Komi
Scandinavian Journal of Medicine & Science in Sports; Early View (Article online in advance of print)

The present study investigated the regulation of leg and joint stiffness in hopping at different intensity levels. Eight male subjects performed bilateral hopping at various intensity levels that were determined by peak vertical ground reaction force (GRF). In addition to the GRF, the measurements included hopping kinematics and electromyography (EMG) of selected leg muscles. While the leg and ankle joint stiffness remained invariant, the knee joint stiffness increased significantly (P<0.01) with the hopping intensity. EMG analysis revealed a significant increase in averaged EMG for all the measured muscles before and during the early phase of ground contact (P<0.05–0.001) with increasing hopping intensity. However, only the vastus lateralis muscle showed significant increase in stretch reflex EMG with increasing hopping intensity (P<0.01). The present study indicates that in hopping with short contact time the leg stiffness modulation is sensitive to changes in ankle joint stiffness and the role of knee joint stiffness is to regulate the jumping performance (height). Furthermore, our results suggest that leg and joint stiffness in hopping is mainly adjusted by centrally programmed motor commands and the contribution of stretch reflexes to muscle force output is muscle-dependent.
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markjohconley · Nov 15, 2010

In the "Running in the Real World" article, it says,
"Experimental observations have revealed that an animal's leg stiffness is independent of both speed and GRAVITY LEVEL, suggesting that it is dictated by inherent musculoskeletal properties. "

Gravity level ? Does this just mean 'independent of what planet we are tested on??????

mike weber · Mar 16, 2011

Walking modeled as a spring mass model - and changes re leg stiffness as speed increases.

Leg stiffness increases with speed to modulate gait frequency and propulsion energy

Leg stiffness increases with speed to modulate gait frequency and propulsion energy

Seyoung Kim, Sukyung Park

Abstract

Bipedal walking models with compliant legs have been employed to represent the ground reaction forces (GRFs) observed in human subjects. Quantification of the leg stiffness at varying gait speeds, therefore, would improve our understanding of the contributions of spring-like leg behavior to gait dynamics. In this study, we tuned a model of bipedal walking with damped compliant legs to match human GRFs at different gait speeds. Eight subjects walked at four different gait speeds, ranging from their self-selected speed to their maximum speed, in a random order. To examine the correlation between leg stiffness and the oscillatory behavior of the center of mass (CoM) during the single support phase, the damped natural frequency of the single compliant leg was compared with the duration of the single support phase. We observed that leg stiffness increased with speed and that the damping ratio was low and increased slightly with speed. The duration of the single support phase correlated well with the oscillation period of the damped complaint walking model, suggesting that CoM oscillations during single support may take advantage of resonance characteristics of the spring-like leg. The theoretical leg stiffness that maximizes the elastic energy stored in the compliant leg at the end of the single support phase is approximated by the empirical leg stiffness used to match model GRFs to human GRFs. This result implies that the CoM momentum change during the double support phase requires maximum forward propulsion and that an increase in leg stiffness with speed would beneficially increase the propulsion energy. Our results suggest that humans emulate, and may benefit from, spring-like leg mechanics.
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markjohconley · Mar 16, 2011

'gravity level', anyone?

mike weber · Mar 17, 2011

markjohconley said: ↑

In the "Running in the Real World" article, it says,
"Experimental observations have revealed that an animal's leg stiffness is independent of both speed and GRAVITY LEVEL, suggesting that it is dictated by inherent musculoskeletal properties. "

Gravity level ? Does this just mean 'independent of what planet we are tested on??????
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markjohconley said: ↑

'gravity level', anyone?
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Hiya Mark, sounds to me that an extra word was used.

If it had of read just Gravity it would make more sense as you suggest we only walk around at the moment on Earth.

markjohconley · Jan 3, 2018

Simon Spooner said: ↑

... Remember, no change in kinematics probably equals no change in axial position.
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Does that still hold; is axial 'position' completely dependent on position?, thanks, mark

mike weber · Jan 3, 2018

Basically, there can be a change in forces acting around axis. But until there is a change in bone position there can be no change in axial position

NewsBot · Jan 17, 2018

Modulation of lower extremity joint stiffness, work and power at different walking and running speeds
Li Jin, Michael E. Hahn
Human Movement Science; Volume 58, April 2018, Pages 1–9

Highlights
•Ankle joint played a dominant role in the stance phase of running.
•Knee and hip joint were dominant in the swing phase of walking and running.
•Running required higher ankle joint stiffness compared to walking.
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Locomotion task and speed changes affect dynamic joint function. Walking and running require different coordination patterns of lower extremity joint mechanics. These coordination differences can result in measurable changes in kinematic and kinetic patterns. When locomotion speed changes, the functional role and movement strategy of each joint is altered. A deeper understanding of joint level mechanics and functional interactions will benefit rehabilitation programs and assistive device development. In this study, joint stiffness, joint mechanical work and power were assessed, as they relate to dynamic function of joints during locomotion. Ten young healthy subjects (5 males, 5 females) participated in a treadmill walking (0.8–2.0 m/s) and running (1.8–3.8 m/s) study. When running speed increased, the stiffness of all three joints tended to increase. The ankle joint played a dominant role during the stance phase of running, generating more positive work than the knee (p = .003) and hip (p = .0001). The knee and hip joint were more dominant in walking and running swing phase energy absorption and generation, respectively. When locomotion speeds increased, stance phase ankle positive work, swing phase knee negative work, and hip joint positive work tended to increase. These findings suggest that change of locomotion speed or task results in definitive changes to lower extremity joint level mechanics patterns.
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mike weber · Jan 17, 2018

NewsBot said: ↑

Modulation of lower extremity joint stiffness, work and power at different walking and running speeds
Li Jin, Michael E. Hahn
Human Movement Science; Volume 58, April 2018, Pages 1–9
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Anyone able to send me the full PDF?

mike weber · Jan 18, 2018

Please

mike weber · Feb 5, 2018

Got myself some tonight reading. So if anyone comes across my question 're full text I have it

NewsBot · Feb 8, 2018

Modulation of lower extremity joint stiffness, work and power at different walking and running speeds
LiJinabMichael E.Hahnab
Human Movement Science; Volume 58, April 2018, Pages 1-9

Highlights
•Ankle joint played a dominant role in the stance phase of running.
•Knee and hip joint were dominant in the swing phase of walking and running.
•Running required higher ankle joint stiffness compared to walking.
Click to expand...

Locomotion task and speed changes affect dynamic joint function. Walking and running require different coordination patterns of lower extremity joint mechanics. These coordination differences can result in measurable changes in kinematic and kinetic patterns. When locomotion speed changes, the functional role and movement strategy of each joint is altered. A deeper understanding of joint level mechanics and functional interactions will benefit rehabilitation programs and assistive device development. In this study, joint stiffness, joint mechanical work and power were assessed, as they relate to dynamic function of joints during locomotion. Ten young healthy subjects (5 males, 5 females) participated in a treadmill walking (0.8–2.0 m/s) and running (1.8–3.8 m/s) study. When running speed increased, the stiffness of all three joints tended to increase. The ankle joint played a dominant role during the stance phase of running, generating more positive work than the knee (p = .003) and hip (p = .0001). The knee and hip joint were more dominant in walking and running swing phase energy absorption and generation, respectively. When locomotion speeds increased, stance phase ankle positive work, swing phase knee negative work, and hip joint positive work tended to increase. These findings suggest that change of locomotion speed or task results in definitive changes to lower extremity joint level mechanics patterns.
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