Gait and Posture 7 (1998) 77–95
Review Paper
The biomechanics of running
Tom F. Novacheck
Motion Analysis Laboratory, Gillette Children’s Specialty Healthcare, Uni6ersity of Minnesota, 200 E. Uni6ersity A6e., St. Paul,
MN 55101, USA
Received 25 August 1997; accepted 22 September 1997
Abstract
This review article summarizes the current literature regarding the analysis of running gait. It is compared to walking and
sprinting. The current state of knowledge is presented as it fits in the context of the history of analysis of movement. The
characteristics of the gait cycle and its relationship to potential and kinetic energy interactions are reviewed. The timing of
electromyographic activity is provided. Kinematic and kinetic data (including center of pressure measurements, raw force plate
data, joint moments, and joint powers) and the impact of changes in velocity on these findings is presented. The status of shoewear
literature, alterations in movement strategies, the role of biarticular muscles, and the springlike function of tendons are addressed.
This type of information can provide insight into injury mechanisms and training strategies. © 1998 Elsevier Science B.V.
Keywords: Running; Biomechanics; Kinematics; Kinetics; Electromyography; Energy; Injury
1. Introduction/history
To avoid the misconception that the analysis of
running is a new area of interest, one need only ex-
amine the art of Grecian vases and consider the writ-
ings of Aristotle, ‘Further, the forces of that which
causes movement and of that which remains still must
be made equal... For just as the pusher pushes, so the
pusher is pushed—i.e. with similar force’ [1]. Leon-
ardo da Vinci’s interest in accuracy in painting in the
15th and 16th centuries increased focus on human
movement and was followed by Newton’s proclama-
tion of his three laws in the 17th century. In 1836, the
Weber brothers (Wilhelm and Eduard) set the agenda
for future research with the most detailed treatise on
walking and running gait to date. They listed 150
hypotheses including that the limb can act as a pen-
dulum. More sophisticated tools were needed than
were currently available to test them. Etienne Jules
Marey (1830–1904) was a prolific pioneer of instru-
mentation. He was among the first to employ photog-
raphy and use it as a true photogrammetric tool. He
also designed and built the first serious force plat-
form. The reader is referred to Cavanagh’s historical
review [2] for further insight into the contributions
and historical significance of the works of Braune,
Fischer, Muybridge, Hill, Fenn, Elftman, and Hub-
bard.
The explosion of interest in running has prompted
a comparable explosion of research and assessment.
This has been potentiated by technical advances in-
cluding faster cameras and marker systems which
eliminate the need to hand digitize frame after frame
of video. The growth of this field has been spurred by
the vast growth in participation in distance running in
the late 1960’s and early 1970’s. Approximately 30
million Americans run for recreation or competition.
The rate of injury is significant. Each year between
1/4 and 1/2 of runners will sustain an injury that is
severe enough to cause a change in practice or perfor-
mance [3,4]. This may lead the runner to seek consul-
tation, alter training, or use medication.
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T.F. No6acheck / Gait and Posture 7 (1998) 77–9578
Because running shoe companies now had a large
new market, they spent part of their profits to support
research. The increased incidence of injury highlighted
the lack of understanding of the pathophysiology and
biomechanics of chronic running injuries. These injuries
are due to repetitive application of relatively small
loads over many repetitive cycles (in sharp distinction
to acute traumatic events such as ACL ruptures in
football—a single large load). The tissues respond dif-
ferently as well [5–7].
It is often the number of repetitions that is problem-
atic. A variety of intrinsic and extrinsic factors have
been blamed for the development of these types of
injuries [3,4,8]. In addition, particular patterns of injury
have been noted. James and Jones [8] noted that almost
75% of complaints fell into six categories (Fig. 1).
Interestingly, one might intuitively think that particular
anatomic abnormalities lead to specific injury patterns
(e.g. hyperpronation predisposing to posterior tibial
syndrome or genu varum leading to iliotibial band
syndrome), but few such relationships have been found.
Given the assumption that greater understanding will
improve diagnosis and counseling, the quandary for the
last two to three decades has been how to make more
sense out of why and how injuries occur.
The volume of literature is extensive; therefore, not
all material can be reviewed or referenced. For the most
part this treatment of the topic will be restricted to
biomechanics and its application to the study of run-
ning gait. Clinical information will be reviewed to the
extent that it focuses one’s attention on the issues at
hand. The reader is referred to articles and chapters
dedicated to the pathophysiology and management of
chronic running injuries [3–7,9–14]. Running Injuries
[15] edited by Gary N. Guten, MD provides a relevant,
recent review of clinical material. These clinical and
pathophysiological issues lie outside the scope of this
article. Several prior review articles [16–21] dedicated
to the biomechanics of running gait are recommended.
These have been invaluable to this author over the
years and are highly recommended. The Biomechanics
of Distance Running edited by Cavanagh [22] is an
essential reference.
Unfortunately, a significant void exists between the
world of the biomechanist and the realm of the clini-
cian. A look at the available literature reveals that the
link between the field of biomechanics and the clinical
realm is difficult to identify. It seems that Dr Stan
James (Eugene, OR, USA) has been the clinician who
has exhibited the greatest understanding of the biome-
chanics of running gait [23]. He has also used biome-
chanical insight to shed light on running injury patterns
[8,24] as have several biomechanists [25,26]. Even
though shoe manufacturers have lead the way in some
areas of biomechanics research, one must wonder
whether a broad spectrum of focus is maintained by
that approach.
2. Gait cycle
How does one go from a standstill to maximum
forward velocity during sprinting? How does the move-
ment strategy change between walking and running
locomotion? The demarcation between walking and
running (Fig. 1, point A) occurs when periods of dou-
ble support during the stance phase of the gait cycle
(both feet are simultaneously in contact with the
ground) give way to two periods of double float at the
beginning and the end of the swing phase of gait
(neither foot is touching the ground). Generally as
speed increases further, initial contact changes from
being on the hindfoot to the forefoot (Fig. 1, point B).
This typically marks the distinction between running
and sprinting. In practicality, the difference between
running and sprinting is in the goal to be achieved.
Running is performed over longer distances, for en-
durance, and with primarily aerobic metabolism. Jog-
ging, road racing, and marathons are examples.
Approximately 80% of distance runners are rearfoot
strikers. Most of the remainder are characterized as
midfoot strikers [27]. Sprinting activities are done over
shorter distances and at faster speeds, with the goal of
covering a relatively short distance in the shortest pe-
riod of time possible without regard for maintaining
aerobic metabolism. Elite sprinters perform with a fore-
foot initial contact, and in fact, the hindfoot may never
contact the ground. For sprinting, the body and its
segments are moved as rapidly as possible throughout
the entire race. For distance running on the other hand,
the body is moved at a more controlled rate in relation
to the energy demand of the race.
The gait cycle is the basic unit of measurement in gait
analysis [28]. The gait cycle begins when one foot comes
in contact with the ground and ends when the same
foot contacts the ground again. These moments in time
are referred to as initial contact. Stance ends when the
foot is no longer in contact with the ground. Toe off
marks the beginning of the swing phase of the gait
cycle. Each of these phases for both walking and run-
ning is subdivided further as seen in Fig. 2. Because the
stance phase in walking is longer than 50% of the gait
cycle, there are two periods of double support when
Fig. 1. Forward human locomotion. At point A, stance phase equals
50% of gait cycle. Periods of double support in walking give way to
periods of double float in running. Point B for the purposes of the
kinematic and kinetic sections of this article represents a change from
hindfoot to forefoot initial contact.