View Full Version : Re: Summary of Responses on Impact Loads in Rearfoot Striking onRunning Injuries

03-22-2010, 01:51 AM

Sorry for weighing in late on this issue.

Clearly, there are no data on injury patterns between runners with
different strike patterns and thus, no conclusions can be made at
this time regarding this relationship. However, there are studies
documenting the lack of impact peak in MFS and FFS as far back as
Cavanagh and Lafortune, 1980.

We have studied the issue of impact loading as it relates to stress
fractures in RFS, and most of our papers have been cited in your
responses from others. More recently, we have found similar
associations with other types of injuries, such as PFPS and plantar
fasciitis. These studies have suggested that some aspect of impact,
including impact peak, instantaneous loadrates, average loadrates or
peak positive tibial acceleration) are significantly higher in the
injured group. While muscle forces do produce the greatest internal
loads on bones and joints, they respond, in part, to the external
forces the body experiences.

Clearly, not all RFS with impact peaks get injured, but these results
suggest that those with higher impact loading are more likely to have
a history of injury.

Studies on this topic, to date. have all been retrospective and thus,
it is unclear whether the increased impact loading seen was the
result or cause of the injury. However, we now have prospective data
that we are currently preparing for manuscript submissions, which we
hope may shed more light on this issue.

Our recent Nature paper suggests that individuals who have never worn
shoes land with MFS or FFS, that is missing the initial quick rise to
peak seen in RFS. Running barefoot with a RFS pattern results in
extremely high rates of loading - and it is very uncomfortable.
Landing with a RFS in shoes reduces the impact peak to some degree,
but the peak is still clearly present. However, landing with a MFS
or FFS in shoes eliminates or markedly attenuates these impacts, and
force patterns become similar to those seen in barefoot conditions.

It has also been shown that FFS patterns are associated with greater
eccentric work of the plantarflexors and increased dorsiflexion
velocity, which may increase risk of injuries to the gastocsoleus or
achilles tendon . Loading in a FFS pattern is mostly concentrated
under the ball of the foot which could lead to increased metatarsal
loading. Therefore a FFS pattern may very well be associated with
different types of injuries than a RFS pattern. It is plausible that
landing with a MFS pattern may be ideal as it reduces the impact
loading, increases the area of the foot over which the force is
distributed and may reduce the work of the plantarflexors.

It is clear from all of the responses that this issue needs further

Thank-you for being the catalyst for a very interesting discussion!

Irene Davis

Irene Davis, PhD, PT, FACSM
Director of Research, Drayer Physical Therapy Institute
Professor, Dept. of Physical Therapy
305 McKinly Lab
University of Delaware
Newark, DE 19716

(302)831-4263 (ph)
(302)831-4234 (fax)


On Mar 20, 2010, at 1:29 AM, Kevin A. Kirby, DPM wrote:

> Colleagues:
> Thank you all for the excellent responses to my question of whether
> the impact peak that is seen specific to rearfoot striking running
> is likely to produce running injuries. I have recently become more
> interested in this topic due to my involvement in debating the
> potential merits of barefoot versus shod running in the popular
> press. In addition, in my private sports podiatry practice, many
> of my runner-patients are curious about the barefoot running fad
> and its potential health/performance implications.
> My personal impression, both from my sports medicine practice and
> from my 40 years as a distance runner, is that rearfoot striking
> and midfoot/forefoot striking running styles are self-selected
> styles of running, neither of which is better or with less injury-
> risk than the other. One thing that I have noted in the clinical
> examination of runners over the past 25 years is that the vast
> majority of runners that tend to naturally choose to be midfoot/
> forefoot strikers (versus choosing to be a rearfoot striker) while
> running shod have restrictions in passive ankle joint dorsiflexion
> with the knee flexed (i.e. soleus/ankle equinus) when compared to
> the rearfoot striking runners. Possibly those runners, while
> running shod, that have adequate ankle joint dorsiflexion with the
> knee flexed will naturally choose to rearfoot strike and those that
> have inadequate ankle joint dorsiflexion with the knee flexed will
> naturally choose to midfoot/forefoot strike at slower running
> speeds? This idea is something certainly to chew on for all of you
> who are looking for potential research projects on this fascinating
> subject.
> Thanks again for all the excellent responses that follow.
> Cheers,
> Kevin
> ************************************************** ********************
> *******
> Kevin A. Kirby, DPM
> Clinical Associate Professor
> Department of Applied Biomechanics
> California School of Podiatric Medicine at Samuel Merritt University
> Private Practice:
> 107 Scripps Drive, Suite 200
> Sacramento, CA 95825 USA
> Voice: (916) 925-8111 (916) 925-8111 Fax: (916) 925-8136
> ************************************************** ********************
> **********
> Dear Dr. Kirby,
> This paper was published in nature and perhaps can help you.
> Lieberman DE, Vankadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis
> IS, Mang’Eni RO, Pitsiladis Y: Foot strike patterns and collision
> forces in habitually barefoot versus shod runners. Nature 463:
> 531-536, 2010.
> Thanks,
> Koosha
> Koosha Aslani M.S.
> Research Engineer, Bioengineering Laboratory
> Department of Orthopaedics
> The Warren Alpert Medical School of Brown University / Rhode Island
> Hospital
> email: kaslani@lifespan.org
> phone: 401-444-4567 401-444-4567
> fax: 401-444-4418
> ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++
> Kevin,
> We met at CSUS while I was in the PT program, and while I was doing
> research with Rafael Escamilla. Hope you're well.
> I'm at University of Delaware now, and research is being conducted
> on your very question. Attached is an abstract.
> Altman AR, Davis IS: Is midfoot striking during running
> advantageous over rearfoot or forefoot striking?
> Toran MacLeod
> Toran MacLeod PT, MS
> PhD Student, BIOMS program
> University of Delaware
> Mechanical Engineering
> 126 Spencer Lab
> 130 Academy St
> Newark, DE 19716
> m. 707.318.2662
> macleod@udel.edu
> ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++
> Kevin,
> Great question and very timely, after Lieberman's recent paper in
> Nature.
> I am not aware of any studies that found an association between impact
> peak or high loading rate and running injuries.
> About 15 years ago I did a thorough review of literature on
> relationship
> between impact load and OA. There have been many attempts to show a
> relationship, but there seems to be no epidemiological evidence
> whatsoever that people who do a lot of running have an earlier
> onset of
> OA. Of course those are not randomized trials, there is a selection
> bias because people tend to stop running when they have pain. But if
> there was any relationship, I think it would have been shown in
> epidemiological studies.
> My explanation is that the external ground reaction force is only a
> minor component of the internal loads on joints and bones. Internal
> forces are several times higher, and mainly generated by muscles.
> Muscles are soft tissue and don't generate or transmit such impact
> peaks. So the bones and joints will hardly notice the impacts.
> The comparative view is also interesting. Metal horseshoes produce
> huge
> impact forces but no injuries.
> Ton van den Bogert
> ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++
> Hi Kevin,
> Here are two you may find interesting, or helpful.
> Regards,
> Rob Kell
> **********************************
> Dr. Robert Kell
> Assistant Professor, Work Physiology
> Dept. of Social Sciences
> University of Alberta
> Augustana Campus
> 4901 - 46 Avenue
> Camrose, AB T4V 2R3
> Phone: (780) 679-1651
> Fax: (780) 679-1590
> email: rob.kell@ualberta.ca
> Boyer, K. A. and T. P. Andriacchi (2009). "Changes in running
> kinematics and kinetics in response to a rockered shoe
> intervention." Clin Biomech (Bristol, Avon) 24(10): 872-6.
> BACKGROUND: A suggested link between ambulatory mechanics and
> injury development has resulted in significant interest the
> development of footwear to change locomotion patterns. The purpose
> of this study was to test the hypothesis that there will be
> significant changes in the kinematics and kinetics at the ankle and
> minimal changes at the knee and hip in the mechanics of running in
> a shoe with a sagittal plane curvature relative to a flat soled
> shoe. METHODS: During running 3-D lower extremity kinematics and
> kinetics for 19 healthy volunteers were quantified using an
> optoelectronics system and a force plate. Data were collected for a
> flat sole conventional shoe (New Balance 658 (Control)) and a shoe
> with a rounded sole in the sagittal plane (Masai Barefoot
> Technologies (MBT)). Data were compared for the two shoe conditions
> using paired Student t-tests (alpha=0.05). FINDINGS: The ankle
> dorsi-flexion angles at heel-strike and mid-stance were greater,
> while the ankle plantar and dorsi-flexion moments and peak ankle
> joint power were significantly lower with the MBT relative to the
> control (P peak anterior GRF peak were also found for running in the MBT shoe.
> INTERPRETATION: Despite a major difference in sole geometry,
> accommodations to the rockered sole were found only at the ankle.
> These results suggest changes in ankle kinematics and kinetics may
> be used to minimize the effect of changes in sole rocker on limb
> dynamics. Thus, changes in shoe rocker may offer potential
> therapeutic opportunities for running related conditions at the
> ankle without substantial risk to the knee or hip.
> Lieberman, D. E., M. Venkadesan, et al. "Foot strike patterns and
> collision forces in habitually barefoot versus shod runners."
> Nature 463(7280): 531-5.
> Humans have engaged in endurance running for millions of years,
> but the modern running shoe was not invented until the 1970s. For
> most of human evolutionary history, runners were either barefoot or
> wore minimal footwear such as sandals or moccasins with smaller
> heels and little cushioning relative to modern running shoes. We
> wondered how runners coped with the impact caused by the foot
> colliding with the ground before the invention of the modern shoe.
> Here we show that habitually barefoot endurance runners often land
> on the fore-foot (fore-foot strike) before bringing down the heel,
> but they sometimes land with a flat foot (mid-foot strike) or, less
> often, on the heel (rear-foot strike). In contrast, habitually shod
> runners mostly rear-foot strike, facilitated by the elevated and
> cushioned heel of the modern running shoe. Kinematic and kinetic
> analyses show that even on hard surfaces, barefoot runners who fore-
> foot strike generate smaller collision forces than shod rear-foot
> strikers. This difference results primarily from a more
> plantarflexed foot at landing and more ankle compliance during
> impact, decreasing the effective mass of the body that collides
> with the ground. Fore-foot- and mid-foot-strike gaits were probably
> more common when humans ran barefoot or in minimal shoes, and may
> protect the feet and lower limbs from some of the impact-related
> injuries now experienced by a high percentage of runners.
> ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++
> Dear Kevin
> It could be helpful maybe.
> http://www.ncbi.nlm.nih.gov/pubmed/9462910
> http://www.asbweb.org/conferences/2009/pdf/1128.pdf
> http://books.google.cz/books?
> id=PrOKEcZXJ58C&pg=PA350&lpg=PA350&dq=forefoot+rearfoot+runner
> +injury
> +risk&source=bl&ots=djHOdLv9hv&sig=1_0QisFtcSqoM08RTg4o6rzM52c&hl=cs&e
> i=Yk6iS7PRDIWomgOp9MD4CQ&sa=X&oi=book_result&ct=result&resnum=7&ved=0C
> CwQ6AEwBg#v=onepage&q=forefoot%20rearfoot%20runner%20injury%
> 20risk&f=false
> http://w4.ub.uni-konstanz.de/cpa/article/viewFile/451/391
> MUDr. Ivan Vareka, Ph.D.
> Department of Biomechanics
> Department of Physiotherapy
> Faculty of Physical Culture
> University of Palacky
> Olomouc
> Czech Republic
> ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++
> You may want to check out
> http://www.youtube.com/user/NatureVideoChannel#p/a/f/0/7jrnj-7YKZE
> for a short video highlighting Daniel Lieberman's research on this
> topic
> at Harvard.
> --
> Kath Bogie, D.Phil
> Senior Research Scientist
> Cleveland FES Center& APT Center, L. Stokes Cleveland VA Medical
> Center
> Website: http://www.aptcenter.research.va.gov
> Assistant Professor (Adjunct)
> Dept of Orthopaedics, Case Western Reserve University
> Dept of Orthopaedics -or- Advanced Platform
> Technology Center of Excellence, 151 AW/APT
> 2109 Adelbert Rd, BRB336 L. Stokes Cleveland VA
> Medical Center
> Case Western Reserve University 10701 East Blvd
> Cleveland, OH 44106 Cleveland, OH 44106
> Phone: (216) 791-3800 X3820 Phone: (216) 368-5270
> FAX: (216) 778-4259 FAX: (216) 707-6420
> ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++
> Hi Dr. Kirby,
> My lab has recently been investigating differences in rearfoot vs.
> forefoot running. Yes, forefoot running does not have the initial
> impact
> peak, but it does not mean the risk of injury less than rearfoot
> runners; it is the type of injury that changes. Rearfoot runners are
> more predisposed to bone injuries whereas forefoot runners are more
> predisposed to muscle, tendon, or ligament injuries; both types are
> from
> repetitive impact loading. Also, although there are studies that
> correlate the passive peak to injury, correlation does not mean
> causation and a link of passive peak to injury is still very
> debated. We
> are presently working on a few manuscripts and hope to publish our
> results soon. Please feel free to let me know if you have any more
> questions.
> --
> Allison Gruber, M.A.
> Doctoral Candidate
> Biomechanics Lab
> Department of Kinesiology
> University of Massachusetts, Amherst
> Totman Building Room 6
> 30 Eastman Lane
> Amherst, MA 01003-9258
> Email: agruber@kin.umass.edu
> ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++
> Dear Kevin,
> You might wish to take a look at the following:
> Biomechanical and anatomic factors associated with a history of
> plantar fasciitis in female runners.
> Pohl MB, Hamill J, Davis IS.
> Clin J Sport Med. 2009 Sep;19(5):372-6.
> PMID: 19741308 [PubMed - indexed for MEDLINE]
> Distinct hip and rearfoot kinematics in female runners with a
> history of tibial stress fracture.
> Milner CE, Hamill J, Davis IS.
> J Orthop Sports Phys Ther. 2010 Feb;40(2):59-66.
> PMID: 20118528 [PubMed - in process]
> Biomechanical predictors of retrospective tibial stress fractures
> in runners.
> Pohl MB, Mullineaux DR, Milner CE, Hamill J, Davis IS.
> J Biomech. 2008;41(6):1160-5. Epub 2008 Apr 2.
> PMID: 18377913 [PubMed - indexed for MEDLINE]
> Repeated application of incremental landing impact loads to intact
> knee joints induces anterior cruciate ligament failure and
> tibiofemoral cartilage deformation and damage: A preliminary
> cadaveric investigation.
> Yeow CH, Ng KS, Cheong CH, Lee PV, Goh JC.
> J Biomech. 2009 May 29;42(8):972-81. Epub 2009 Apr 19.
> PMID: 19380143 [PubMed - indexed for MEDLINE
> Mechanical impact and articular cartilage.
> Scott CC, Athanasiou KA.
> Crit Rev Biomed Eng. 2006;34(5):347-78. Review.
> PMID: 17206919 [PubMed - indexed for MEDLINE]
> My best,
> Katherine
> Katherine K. Whitcome
> Assistant Professor
> Department of Anthropology
> 446 Braunstein Hall
> PO Box 210380
> University of Cincinnati
> Cincinnati, Ohio 45221-0380
> Office: 513-556-0369 513-556-0369
> katherine.whitcome@uc.edu
> ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++
> Hi Kevin,
> Have you seen the Lieberman studies in Nature?
> Vol 463, 28 Jan, 2010, p 531
> Vol 432, 18 Nov, 2004, p 345
> http://www.nature.com/news/2010/100126/full/news.2010.36.html
> You may recognize the name Daniel Lieberman, who has done a few
> studies on barefoot running, which would produce midfoot and
> forefoot strike. His most recent article (Jan. 2010) speaks to the
> habitually barefoot vs. habitually shot runners, but I'm not sure
> it is specific to injury. Maybe you have seen this already?
> Also The Science of Sport blog (http://www.sportsscientists.com/)
> is doing a series of posts on barefoot running, which may be
> helpful for references and general thought provoking discussion.
> I am VERY interested in this topic so please share what you might
> find.
> Thanks and good luck!
> Laura Gilmour
> ++++++++++++++++++++++++++++++++++++++++++++++++++ +++
> Dr. Irene Davis in my dept has ongoing research on this.
> Best,
> Cole Galloway
> ======================================
> James C. (Cole) Galloway, PT, PhD
> Director, Infant Motor Behavior Lab
> Associate Professor, Dept of Physical Therapy
> Biomechanics and Movement Sciences Program
> 311 McKinly Lab
> University of Delaware
> Newark, DE USA 19716
> Phone: 302.831.3697(office), x3214 (lab), x4234 (fax)
> http://www.udel.edu/PT/About%20Us/People/galloway.html
> ++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++
> Hi Kevin,
> I recently did a lit review on running injuries for a chapter in my
> dissertation (happy to share this if you're interested). A summary
> of the major points:
> (1) The reported injury rates in epidemiological literature have
> not changed since the 1980s; if you average across studies within a
> decade, in the '80s, '90s, and 2000s, the yearly injury rate is
> about 40% in each decade. However, within that 40%, the rates of
> specific injuries have changed somewhat. Achilles tendinitis rates
> seem to have gone down, while knee injuries and stress fractures
> have gone up. Whether this is due to actual changes in injury
> susceptibility and prevention, or just changes in the reporting of
> or definition of injuries, I don't know.
> (2) I only came across one study that reported greater vertical GRF
> impact peaks in the "injured" group (Hreljac et al., 2000, in
> MSSE). Literally every other study looking at impact peaks in
> healthy and injury-prone runners found no significant difference.
> However, there are several studies that have greater vertical
> impact loading rates in injury-prone runners. A couple that come
> to mind are the Hreljac study, and Milner et al. (2006), a stress
> fracture study. Since nearly all biological tissues are at least
> somewhat visco-elastic, loading rates may be important injury factors.
> (3) There is a huge lack of prospective studies on specific running
> injuries. I think Noerhen et al. (2007) looked at the GRF in
> runners who prospectively developed ITBS and didn't find any
> differences. Benno Nigg has a review paper in 1995 (Journal of
> Applied Biomechanics) where he cites a masters thesis that found
> greater impact peaks in the runners who prospectively developed
> injuries, but the study was never published to my knowledge.
> My current thought is that the impact peak doesn't actually vanish
> in the forefoot strike (there still has to be impulsive contact
> with the ground, regardless of the foot posture), but it gets
> "swallowed up" by the active peak, which occurs sooner due to the
> shorter stride length and consequently the resultant GRF being
> oriented more directly through the body's mass center. I think
> runners can likely move the forces around and change when and where
> they happen by adjusting footstrike patterns. What this means
> regarding injury potential, I'm not sure. Tim Derrick had a
> conference proceeding several years ago on extracting the impact
> peak from the vertical GRF:
> http://www.asbweb.org/conferences/2005/pdf/0773.pdf
> It may be interesting to perform this analysis on GRF from both
> rearfoot and forefoot striking.
> Hope this helps,
> Ross
> ============
> Ross H. Miller
> Doctoral candidate, Dept. of Kinesiology
> University of Massachusetts
> ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++
> Hi Kevin,
> I've attached a paper that I wrote during my time working with Irene
> Davis. We found greater vertical GRF load rates associated with
> runners
> who had a history of plantar fasciitis. However, all the subjects
> were
> rearfoot strikers so it's impossible to attribute the injury
> history to
> the foot strike pattern. Reed and myself are currently tackling the
> question of whether midfoot/forefoot strike patterns are more
> beneficial
> than a rearfoot strike pattern. The bottom line is that there is no
> evidence to suggest that one pattern may be more beneficial than
> the other
> in preventing injury!
> Hope all is going well for you.
> Cheers,
> Mike
> _____________________
> Postdoctoral Fellow
> Running Injury Clinic
> University of Calgary
> 2500 University Drive NW
> Calgary, Alberta, CANADA
> T2N 1N4
> P: 403-210-8501 403-210-8501
> F: 403-220-0546
> ++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++
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