Med Sci Sports Exerc. 2014 Mar;46(3):580-5. doi: 10.1249/MSS.0000000000000139.

Rearfoot striking runners are more economical than midfoot strikers.

Ogueta-Alday A(1), Rodríguez-Marroyo JA, García-López J.

Author information:
(1)Department of Physical Education and Sports, Institute of Biomedicine (IBIOMED),
University of León, León, SPAIN.

PURPOSE: This study aimed to analyze the influence of foot strike pattern on
running economy and biomechanical characteristics in subelite runners with a
similar performance level.
METHODS: Twenty subelite long-distance runners participated and were divided into
two groups according to their foot strike pattern: rearfoot (RF, n = 10) and
midfoot (MF, n = 10) strikers. Anthropometric characteristics were measured
(height, body mass, body mass index, skinfolds, circumferences, and lengths);
physiological (VO2max, anaerobic threshold, and running economy) and
biomechanical characteristics (contact and flight times, step rate, and step
length) were registered during both incremental and submaximal tests on a
treadmill.
RESULTS: There were no significant intergroup differences in anthropometrics,
VO2max, or anaerobic threshold measures. RF strikers were 5.4%, 9.3%, and 5.0%
more economical than MF at submaximal speeds (11, 13, and 15 km·h respectively,
although the difference was not significant at 15 km·h, P = 0.07). Step rate and
step length were not different between groups, but RF showed longer contact time
(P < 0.01) and shorter flight time (P < 0.01) than MF at all running speeds.
CONCLUSIONS: The present study showed that habitually rearfoot striking runners
are more economical than midfoot strikers. Foot strike pattern affected both
contact and flight times, which may explain the differences in running economy.

PMID: 24002340 [PubMed – in process]
J Orthop Sports Phys Ther. 2013 Oct;43(10):685-92. doi: 10.2519/jospt.2013.4542.
Epub 2013 Sep 9.

A comparison of negative joint work and vertical ground reaction force loading rates in Chi runners and rearfoot-striking runners.

Goss DL(1), Gross MT.

Author information:
(1)US Army-Baylor University Doctoral Program in Physical Therapy, Fort Sam Houston,
TX.

STUDY DESIGN: Observational.
OBJECTIVES: To compare lower extremity negative joint work and vertical ground
reaction force loading rates in rearfoot-striking (RS) and Chi runners.
BACKGROUND: Alternative running styles such as Chi running have become a popular
alternative to RS running. Proponents assert that this running style reduces knee
joint loading and ground reaction force loading rates.
METHODS: Twenty-two RS and 12 Chi runners ran for 5 minutes at a self-selected
speed on an instrumented treadmill. A 3-D motion analysis system was used to
obtain kinematic data. Average vertical ground reaction force loading rate and
negative work of the ankle dorsiflexors, ankle plantar flexors, and knee
extensors were computed during the stance phase. Groups were compared using a
1-way analysis of covariance for each variable, with running speed and age as
covariates.
RESULTS: On average, RS runners demonstrated greater knee extensor negative work
(RS, -0.332 J/body height × body weight [BH·BW]; Chi, -0.144 J/BH·BW; P<.001),
whereas Chi runners demonstrated more ankle plantar flexor negative work (Chi,
-0.467 J/BH·BW; RS, -0.315 J/BH·BW; P<.001). RS runners demonstrated greater
average vertical ground reaction force loading rates than Chi runners (RS, 68.6
BW/s; Chi, 43.1 BW/s; P<.001).
CONCLUSION: Chi running may reduce vertical loading rates and knee extensor work,
but may increase work of the ankle plantar flexors.

PMID: 24256170 [PubMed – in process]
J Strength Cond Res. 2013 Jul 15. [Epub ahead of print]

The relationship of foot strike pattern, shoe type, and performance in a 50-km trail race.

Kasmer ME(1), Liu XC, Roberts KG, Valadao JM.

Author information:
(1)1Department of Physical Medicine & Rehabilitation, Medical College of Wisconsin,
Milwaukee, Wisconsin; 2Department of Orthopedic Surgery, Medical College of
Wisconsin, Milwaukee, Wisconsin; 3Footworks Orthotics Incorporated, Milwaukee,
Wisconsin; 4Medical College of Wisconsin, Milwaukee, Wisconsin.

Recent “in-race” studies have observed the foot strike patterns of runners in
traditional road marathon races. However, similar studies have not been conducted
for trail runners, which have been estimated to account for 11% of all runners.
The purpose of this study was to: 1) determine the rear-foot strike (RFS)
prevalence in a 50 km trail race and compare with traditional road marathon
races; 2) determine if there is a relationship between foot strike and sex in a
50 km trail race; and 3) determine if there is a relationship between foot
strike, shoe type, and performance in a 50 km trail race. 165 runners were
videotaped at the 8.1 km mark of the 2012 Ice Age Trail 50 km race. Foot strike
analysis revealed RFS prevalence of 85.1%, less than previously reported in
traditional road marathon races. There was no relationship found between sex and
foot strike (p=0.60). A significant effect of shoe type on foot strike (RFS was
less common among runners in minimalist shoes, p<0.01) and performance (faster
runners were more likely to be wearing minimalist shoes, p<0.01) was observed;
however, no association between foot strike and performance was observed
(p=0.83). This study suggests that most trail runners, albeit less than road
runners, prefer a RFS pattern, which is accompanied by biomechanical consequences
unique from a non-RFS pattern and therefore, likely carries a unique injury
profile. In addition, the findings in this study suggest that minimalist shoes
may represent a reasonable training modification to improve performance.

PMID: 23860289 [PubMed – as supplied by publisher]
Gait Posture. 2013 Jul;38(3):490-4. doi: 10.1016/j.gaitpost.2013.01.030. Epub
2013 Mar 16.

Is the foot striking pattern more important than barefoot or shod conditions in running?

Shih Y(1), Lin KL, Shiang TY.

Author information:
(1)Graduation Institute of Exercise and Sports Science, National Taiwan Normal
University, No. 88, Sec. 4, Tingzhou Rd., Wenshan Dist., Taipei City 116, Taiwan.

People have advocated barefoot running, claiming that it is better suited to
human nature. Humans usually run barefoot using a forefoot strike and run shod
using a heel strike. The striking pattern was thought to be a key factor that
contributes to the benefit of barefoot running. The purpose of this study is to
use scientific data to prove that the striking pattern is more important than
barefoot or shod conditions for runners on running injuries prevention. Twelve
habitually male shod runners were recruited to run under four varying conditions:
barefoot running with a forefoot strike, barefoot running with a heel strike,
shod running with a forefoot strike, and shod running with a heel strike. Kinetic
and kinematic data and electromyography signals were recorded during the
experiments. The results showed that the lower extremity can gain more compliance
when running with a forefoot strike. Habitually shod runners can gain more shock
absorption by changing the striking pattern to a forefoot strike when running
with shoes and barefoot conditions. Habitually shod runners may be subject to
injuries more easily when they run barefoot while maintaining their heel strike
pattern. Higher muscle activity in the gastrocnemius was observed when running
with a forefoot strike, which may imply a greater training load on the muscle and
a tendency for injury.

Copyright © 2013 Elsevier B.V. All rights reserved.

PMID: 23507028 [PubMed – indexed for MEDLINE]
Int J Sports Physiol Perform. 2013 May;8(3):286-92. Epub 2012 Sep 19.

Foot-strike pattern and performance in a marathon.

Kasmer ME(1), Liu XC, Roberts KG, Valadao JM.

Author information:
(1)Dept of Physical Medicine and Rehabilitation, Medical College of Wisconsin,
Milwaukee, WI, USA.

PURPOSE: To determine prevalence of heel strike in a midsize city marathon, if
there is an association between foot-strike classification and race performance,
and if there is an association between foot-strike classification and gender.
METHODS: Foot-strike classification (forefoot, midfoot, heel, or split strike),
gender, and rank (position in race) were recorded at the 8.1-km mark for 2112
runners at the 2011 Milwaukee Lakefront Marathon.
RESULTS: 1991 runners were classified by foot-strike pattern, revealing a
heel-strike prevalence of 93.67% (n = 1865). A significant difference between
foot-strike classification and performance was found using a Kruskal-Wallis test
(P < .0001), with more elite performers being less likely to heel strike. No
significant difference between foot-strike classification and gender was found
using a Fisher exact test. In addition, subgroup analysis of the 126 non-heel
strikers found no significant difference between shoe wear and performance using
a Kruskal-Wallis test.
CONCLUSIONS: The high prevalence of heel striking observed in this study reflects
the foot-strike pattern of most mid-distance to long-distance runners and, more
important, may predict their injury profile based on the biomechanics of a
heel-strike running pattern. This knowledge can help clinicians appropriately
diagnose, manage, and train modifications of injured runners.

PMID: 23006790 [PubMed – indexed for MEDLINE]
PLoS One. 2013;8(1):e52548. doi: 10.1371/journal.pone.0052548. Epub 2013 Jan 9.

Variation in foot strike patterns during running among habitually barefoot
populations.

Hatala KG(1), Dingwall HL, Wunderlich RE, Richmond BG.

Author information:
(1)Hominid Paleobiology Doctoral Program, The George Washington University,
Washington, DC, USA. kghatala@gwmail.gwu.edu

Endurance running may have a long evolutionary history in the hominin clade but
it was not until very recently that humans ran wearing shoes. Research on modern
habitually unshod runners has suggested that they utilize a different
biomechanical strategy than runners who wear shoes, namely that barefoot runners
typically use a forefoot strike in order to avoid generating the high impact
forces that would be experienced if they were to strike the ground with their
heels first. This finding suggests that our habitually unshod ancestors may have
run in a similar way. However, this research was conducted on a single population
and we know little about variation in running form among habitually barefoot
people, including the effects of running speed, which has been shown to affect
strike patterns in shod runners. Here, we present the results of our
investigation into the selection of running foot strike patterns among another
modern habitually unshod group, the Daasanach of northern Kenya. Data were
collected from 38 consenting adults as they ran along a trackway with a plantar
pressure pad placed midway along its length. Subjects ran at self-selected
endurance running and sprinting speeds. Our data support the hypothesis that a
forefoot strike reduces the magnitude of impact loading, but the majority of
subjects instead used a rearfoot strike at endurance running speeds. Their
percentages of midfoot and forefoot strikes increased significantly with speed.
These results indicate that not all habitually barefoot people prefer running
with a forefoot strike, and suggest that other factors such as running speed,
training level, substrate mechanical properties, running distance, and running
frequency, influence the selection of foot strike patterns.

PMCID: PMC3541372
PMID: 23326341 [PubMed – indexed for MEDLINE]
Sports Health. 2012 Nov;4(6):480-4. doi: 10.1177/1941738112448055.

Is there evidence to support a forefoot strike pattern in barefoot runners? A review.

Lorenz DS(1), Pontillo M.

Author information:
(1)Specialists in Sports and Orthopedic Rehabilitation, Overland Park, Kansas.

CONTEXT: Barefoot running is a trend among running enthusiasts that is the
subject of much controversy. At this time, benefits appear to be more speculative
and anecdotal than evidence based. Additionally, the risk of injuries is not well
established.
EVIDENCE ACQUISITION: A PubMed search was undertaken for articles published in
English from 1980 to 2011. Additional references were accrued from reference
lists of research articles.
RESULTS: While minimal data exist that definitively support barefoot running,
there are data lending support to the argument that runners should use a forefoot
strike pattern in lieu of a heel strike pattern to reduce ground reaction forces,
ground contact time, and step length.
CONCLUSIONS: Whether there is a positive or negative effect on injury has yet to
be determined. Unquestionably, more research is needed before definitive
conclusions can be drawn.

PMCID: PMC3497946
PMID: 24179586 [PubMed]
US Army Med Dep J. 2012 Jul-Sep:62-71.

A review of mechanics and injury trends among various running styles.

Goss DL(1), Gross MT.

Author information:
(1)University of North Carolina, Chapel Hill, NC, USA.

CONTEXT: Running related overuse injuries are a significant problem with half of
all runners sustaining an injury annually. Many medical providers and coaches
question how to advise their running clients to prevent injuries. Alternative
running styles with a more anterior footstrike such as barefoot running, POSE
running, and Chi running are becoming more popular. Little information, however,
has been published comparing the mechanics and injury trends of different running
styles.
OBJECTIVE: The original purpose of this paper was to examine evidence concerning
the biomechanics and injury trends of different running styles. Little to no
injury data separated by running style existed. Therefore, we discuss the
biomechanics of different running styles and present biomechanical findings
associated with different running injuries.
DATA SOURCES: English language articles published in peer reviewed journals were
identified by searching PubMed, CINAHL, and SPORTDiscus databases. Nearly all of
the studies identified by the search were observational studies.
RESULTS: A more anterior initial foot contact present in barefoot or other
alternative running styles may decrease or eliminate the initial vertical ground
reaction peak or “impact transient,” possibly reducing knee joint loads and
injuries. A more anterior foot strike, however, may increase mechanical work at
the ankle and tensile stress within the plantarflexors. Wearing minimal footwear
may also increase contact pressure imposed on the metatarsals.
CONCLUSION: More research is needed to determine which individuals with certain
morphological or mechanical gait characteristics may benefit from alternative
running styles that incorporate a more anterior initial foot contact with or
without shoes.

PMID: 22815167 [PubMed – indexed for MEDLINE]
J Sports Sci. 2012;30(13):1347-63. doi: 10.1080/02640414.2012.710755. Epub 2012
Jul 30.

A review of models of vertical, leg, and knee stiffness in adults for running, jumping or hopping tasks.

Serpell BG(1), Ball NB, Scarvell JM, Smith PN.

Author information:
(1)Canberra Hospital, Trauma and Orthopaedic Research Unit, Woden, Australia.
ben.serpell@gmail.com

The ‘stiffness’ concept originates from Hooke’s law which states that the force
required to deform an object is related to a spring constant and the distance
that object is deformed. Research into stiffness in the human body is undergoing
unprecedented popularity; possibly because stiffness has been associated with
sporting performance and some lower limb injuries. However, some inconsistencies
surrounding stiffness measurement exists bringing into question the integrity of
some research related to stiffness. The aim of this study was to review
literature which describes how vertical, leg and knee stiffness has been measured
in adult populations while running, jumping or hopping. A search of the entire
MEDLINE, PubMed and SPORTDiscus databases and an iterative reference check was
performed. Sixty-seven articles were retrieved; 21 measured vertical stiffness,
51 measured leg stiffness, and 22 measured knee stiffness. Thus, some studies
measured several ‘types’ of stiffness. Vertical stiffness was typically the
quotient of ground reaction force and centre of mass displacement. For leg
stiffness it was and change in leg length, and for the knee it was the quotient
of knee joint moments and change in joint angle. Sample size issues and
measurement techniques were identified as limitations to current research.

PMID: 22845059 [PubMed – indexed for MEDLINE]
J Sports Sci. 2011 Dec;29(15):1665-73. doi: 10.1080/02640414.2011.610347. Epub
2011 Nov 18.

Foot strike patterns of recreational and sub-elite runners in a long-distance road race.

Larson P(1), Higgins E, Kaminski J, Decker T, Preble J, Lyons D, McIntyre K,
Normile A.

Author information:
(1)Department of Biology, St. Anselm College, Manchester, New Hampshire 03102, USA.
plarson@anselm.edu

Although the biomechanical properties of the various types of running foot strike
(rearfoot, midfoot, and forefoot) have been studied extensively in the
laboratory, only a few studies have attempted to quantify the frequency of
running foot strike variants among runners in competitive road races. We
classified the left and right foot strike patterns of 936 distance runners, most
of whom would be considered of recreational or sub-elite ability, at the 10 km
point of a half-marathon/marathon road race. We classified 88.9% of runners at
the 10 km point as rearfoot strikers, 3.4% as midfoot strikers, 1.8% as forefoot
strikers, and 5.9% of runners exhibited discrete foot strike asymmetry. Rearfoot
striking was more common among our sample of mostly recreational distance runners
than has been previously reported for samples of faster runners. We also compared
foot strike patterns of 286 individual marathon runners between the 10 km and 32
km race locations and observed increased frequency of rearfoot striking at 32 km.
A large percentage of runners switched from midfoot and forefoot foot strikes at
10 km to rearfoot strikes at 32 km. The frequency of discrete foot strike
asymmetry declined from the 10 km to the 32 km location. Among marathon runners,
we found no significant relationship between foot strike patterns and race times.

PMID: 22092253 [PubMed – indexed for MEDLINE]
J Strength Cond Res. 2007 Aug;21(3):888-93.

Foot strike patterns of runners at the 15-km point during an elite-level half marathon.

Hasegawa H(1), Yamauchi T, Kraemer WJ.

Author information:
(1)Laboratory of Exercise Science, Department of Business Management, Ryukoku
University, Kyoto, Japan. hiroshi515@aol.com

There are various recommendations by many coaches regarding foot landing
techniques in distance running that are meant to improve running performance and
prevent injuries. Several studies have investigated the kinematic and kinetic
differences between rearfoot strike (RFS), midfoot strike (MFS), and forefoot
strike (FFS) patterns at foot landing and their effects on running efficiency on
a treadmill and over ground conditions. However, little is known about the actual
condition of the foot strike pattern during an actual road race at the elite
level of competition. The purpose of the present study was to document actual
foot strike patterns during a half marathon in which elite international level
runners, including Olympians, compete. Four hundred fifteen runners were filmed
by 2 120-Hz video cameras in the height of 0.15 m placed at the 15.0-km point and
obtained sagittal foot landing and taking off images for 283 runners. Rearfoot
strike was observed in 74.9% of all analyzed runners, MFS in 23.7%, and FFS in
1.4%. The percentage of MFS was higher in the faster runners group, when all
runners were ranked and divided into 50 runner groups at the 15.0-km point of the
competition. In the top 50, which included up to the 69th place runner in actual
order who passed the 15-km point at 45 minutes, 53 second (this speed represents
5.45 m x s(-1), or 15 minutes, 17 seconds per 5 km), RFS, MFS, and FFS were 62.0,
36.0, and 2.0%, respectively. Contact time (CT) clearly increased for the slower
runners, or the placement order increased (r = 0.71, p < or = 0.05). The CT for
RFS + FFS for every 50 runners group significantly increased with increase of the
placement order. The CT for RFS was significantly longer than MFS + FFS (200.0
+/- 21.3 vs. 183.0 +/- 16 millisecond). Apparent inversion (INV) of the foot at
the foot strike was observed in 42% of all runners. The percentage of INV for MFS
was higher than for RFS and FFS (62.5, 32.0, and 50%, respectively). The CT with
INV for MFS + FFS was significantly shorter than the CT with and without INV for
RFS. Furthermore, the CT with INV was significantly shorter than push-off time
without INV for RFS. The findings of this study indicate that foot strike
patterns are related to running speed. The percentage of RFS increases with the
decreasing of the running speed; conversely, the percentage of MFS increases as
the running speed increases. A shorter contact time and a higher frequency of
inversion at the foot contact might contribute to higher running economy.

PMID: 17685722 [PubMed – indexed for MEDLINE]