Kinematic Analysis of Olympic Hurdle Performance: Women`s 100

INTERNATIONAL JOURNAL OF SPORT BIOMECHANICS, 1985, 1, 163-173
Kinematic Analysis
of Olympic Hurdle Performance:
Women's 100 Meters
Ralph Mann and john Herman
CompuSporf, Inc., Ocala, FL
Selected kinematic variables in the performance of the Gold and Silver medalists and
the eighth-place finisher in the women's 100-meter hurdles final at the 1984 Summer
Olympic Games were investigated. Cinematographicrecords were obtained for all track
hurdling events at the Games, with the 100-meter hurdle performers singled out for
initial analysis. In this race, sagittal view filming records (100 fps) were collected at
the 9th hurdle of the performance. Computer generated analysis variables included
both direct performance variables (body velocity, support time, etc.) and body kinematics
(upper leg position, lower leg velocity, etc.) that have previously been utilized in the
analysis of elite athlete hurdlers. The difference in place finish was related to the performance variables body horizontal velocity (direct), vertical velocity (indirect), and
support time (indirect). The critical body kinematics variables related to success included upper and lower leg velocity during support into and off the hurdle (direct),
relative horizontal foot position (to the body) at touchdown into and off the hurdle
(indirect), and relative horizontal foot velocity (to the body) at touchdown into the hurdle.
The coordinated effort to film a number of events for scientific study during the
1984 Summer Olympic Games has provided a unique data base for the study of elite performances. Although several studies have been performed on athletes at a performance
level termed "elite," quantitative results on Olympic or other truly elite performers are
virtually nonexistent in the majority of sports. Moreover, those few studies that have utilized
true elite athletes have found significant differences between the top world-class performers
and the typical collegiate-caliber athlete most often labeled elite.
The purpose of this study was to utilize the data collected on the Olympic hurdle
(short and long) events to demonstrate the analysis potential of the data collected during
the 1984 Games. Since the performances were filmed using standard biomechanical procedures, the data can provide quality results on a wide variety of total body and individual
segment variables.
In reviewing the literature pertinent to the hurdle event, quantitative studies are
greatly lacking in regard to this skill. With the exception of technical reports prepared
Direct all correspondence to Ralph Mann, CompuSport, Inc., Box 4262, Ocala, FL 32678.
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MANN AND HERMAN
for the United States Olympic Committee (Mann, Herman, Johnson, Schultz, & Kotmel,
1982, 1983; Ward & India, 1978), no comprehensive quantitative analysis of hurdling
is available. Moreover, Ward and India only investigated the men's hurdle events.
Due to the lack of quantitative information, a review of the qualitative studies,
comments, articles and opinions available can generally be regarded as being in agreement with one another in describing the mechanics of the hurdling motion. For the purpose of clarity, the following review has been divided into two areas: direct pe$onnance
descriptors and body kinematics. Direct performance descriptors are those variables most
often used to describe a hurdler's overall performance, (i.e., horizontal velocity, hurdle
time, etc.). Although these variables give little insight regarding how a performer is physically producing the performance, they are critical in determining the level and nature of the
effort. Body kinematics include those movement patterns that actually produce the performance (i.e., upper leg angular velocity, lower leg angular position, etc.). If the proper
results in this category are analyzed, insight into how the direct performance descriptors
are produced can be gained.
Of all the direct performance descriptors, it is generally agreed that success in
hurdling depends mainly upon the hurdler maintaining horizontal velocity throughout the
hurdle stride. Bush and Valentine (1974) state that upon approach in preparation for takeoff,
the hurdler should not gather, as this will break forward motion. Calhoun (1976) adds
that the hurdler should not take an exaggerated step in preparation for takeoff in an attempt to brake and make adjustments. This will only sacrifice previously generated sprinting speed. This is in agreement with Mann et al. (1982-1983), who found that the relationship of the foot to the body center of gravity at touchdown was similar to that in sprinting. In contrast, Sipes (1976) claims that the last step prior to the hurdle should be shortened
so the hurdler can shift the center of gravity forward for better position for takeoff.
- The normal body lean of a sprinter should be maintained during the takeoff stride
and accentuated during clearance. The aim should be to drive the body out and over the
hurdle, not up and over as in the high jump (Cooper, Lavery, & Perrin, 1970; Mann et
al., 1982-1983). Numerous qualitative articles (Cooper, Lavery, & Perrin, 1970; Costanza
& Glossbrenner, 1978; Justin, 1970; Lawson, 1978; McFarlane, 1976; Sipes, 1976) state
the importance of leaning over the thigh of the lead leg during clearance, the primary
purpose being to keep the body center of gravity as close to the path it follows in normal
sprinting as the hurdle height will permit.
Since vertical velocity into the hurdle should be minimized, the hurdle stride should
also be as short as possible (Mann et al., 1982-1983). Additionally, the stride distance
before the hurdle should be greater than the length after the hurdle. This allows the performer to reach a vertical peak prior to the hurdle, allowing the lead leg to regain ground
contact faster and in a superior landing position (Cooper, Lavery, & Perrin, 1970; Sipes,
1976).
As in sprinting, both ground and air times should be as short as possible. Proper
body segment positioning at touchdown, both into and off the barrier, and minimal vertical projection into the hurdle, is the key to minimizing hurdle times (Mann et al.,
1982-1983).
Of all the body kinematic results, Mann et al. (1982-1983) have identified the
upper leg as the most critical body segment in hurdling. At touchdown, both into and off
the hurdle, high extension velocity is beneficial in limiting the amount of horizontal braking. Maintenance of upper leg extension velocity during ground contact serves to propel
WOMEN'S 100 METERS
165
the performer into the hurdle (before) and toward the next barrier (after). These concepts
are supported by the qualitative conclusions of Gordon (1966), Justin (1970), Bush and
Valentine (1974), Lawson (1978), and Chisam (1980).
Great importance has been placed upon the movement of the lower leg during
hurdle clearance. Going into the hurdle, the lower leg on the ground should be flexing
at touchdown (to reduce the horizontal braking), then powerfully extending at takeoff (to
drive the performer into the hurdle) (Mann et al., 1982-1983). At the same time, the lower
leg of the lead leg should be quickly flexed to reduce the moment of inertia about the
hip, enabling the leg to be rotated forward more rapidly (McFarlane, 1976; Sipes, 1976).
When the upper leg reaches parallel, momentum will be transferred to the lower leg by
extending the knee joint. Mann et al. (1982, 1983) found this trend of efficient lead leg
recovery critical to hurdle performance among elite performers.
During the hurdle flight the concensus opinion (Bush & Valentine, 1974; Lawson,
1978; McFarlane, 1976; Sipes, 1976) is that the lead lower leg should be kept slightly
flexed, and not completely extended. Justin (1970) claims that a straight leg will normally
cause the upper body to straighten with a consequent loss of speed. Furthermore, Justin
(1970) and McFarlane (1976) both state that a straight leg will delay the downward swing
of the entire leg after hurdle clearance and result in an awkward landing position, while
a flexed leg permits the foot to start downward almost as soon as it has crossed the hurdle.
After propelling the hurdler into the barrier, the ground leg becomes the trail leg.
The lower leg motion is believed to be a major factor in proper trail leg recovery. Several
authors (Cooper, Lavery, & Perrin, 1970; Costanza & Glossbrenner, 1978; Gordon, 1966;
Jackson, 1968; Lawson, 1978; Sipes, 1976) discuss the importance of "delaying" the
flexion of the trail lower leg, not to bring the trail leg through too soon. Cooper, Lavery,
and Perrin (1970), McFarlane (1976), and Costanza and Glossbrenner (1978) all claim
that this will ensure a full leg split at takeoff (scissors action) that will keep the hurdler
close to the ground and enable the performer to have a forward lean at takeoff. Costanza
and Glossbrenner (1978) further state that bringing the trail leg through too soon will cause
the hurdler to leap or jump over the hurdle, increasing air time. Jackson (1968) and Costanza
and Glossbrenner (1978) also state that not delaying the trail leg will cause the feet to
land too close together coming off the hurdle, throwing the hurdler off balance and making it difficult to run three strides between hurdles. Finally, a delayed trail leg will allow
for continuous sprinter action and balance (Lawson, 1978).
At touchdown coming off the hurdle, the lower leg should be flexing to minimize
the horizontal braking at impact. In addition, flexion should continue through ground contact
as the hurdler emphasizes forward (not upward) projection toward the next barrier (Mann
et al., 1982-1983).
The action of the upper and lower legs dictates the position and movement of the
foot. In hurdling, the foot position and velocity results have been used to ascertain the
quality of performance. Both going into and coming off the hurdle, it is a well supported
belief that the foot should be placed as close under the body as possible to avoid horizontal braking (Chisam, 1980; Justin, 1970; Mann et al., 1982-1983; McInnis, 1978; Sipes,
1976). This is especially true coming off the hurdle, where it is possible to land directly
under the body.
Along with proper foot position, a high backward foot velocity (with respect to
the body) can further decrease the horizontal braking at touchdown (Mann et al.,
1982-1983). Although the backward velocity of the foot cannot match the forward veloci-
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MANN AND HERMAN
ty of the body going into the hurdle (some braking will always occur), superior performers
can actually match or exceed the body velocity at touchdown coming off the hurdle (virtually no braking occurs).
Methods
The data acquired for this study were collected during the 1984 Summer Olympic Games.
Data reduction and analysis followed procedures that were previously developed for the
investigation of elite-class hurdlers (Mann et al., 1982-1983).
Data Collection
The potential subjects consisted of all hurdle (short and long) finalists in the 1984 Summer
Olympic Games. For purposes of this analysis, investigation was limited to first (Gold),
second (Silver), and eighth-place finishers in the 100-meter hurdles for women.
All potential subjects were filmed during the finals of the Olympic Games track
events between August 4 and August 10. The finals in the 100-meter hurdles for women
occurred on August 10. Filming was done at ground level with one Locam, motor-driven,
16mm camera equipped with an Angineaux 12-120rnm lens. The camera was positioned
to film the sagittal view of the eight finalists, with a filming rate of 100 frames per second, as they negotiated the 9th hurdle. Film speed was corroborated with an internal
100 cycle/second pulse generator contained in the camera. The camera was positioned
to produce a field of view sufficient to record the airborne portion of the penultimate stride,
the entire hurdle stride, and the ground portion of the recovery stride for the performer
in the lane closest to the camera. A one-meter multiplier was filmed in each of the eight
lanes to allow for proper scaling during data reduction.
Data Reduction and Analysis
The displacement data were reduced from the film using an Altek digitizer interfaced into
a DEC Rainbow 100 computer. The results were then sent to a DEC VAX 111750 computer for processing. The body parameters of interest were then generated with the aid
of a program developed by Mann (1979).
The direct performance descriptors of support time and nonsupport time into, over,
and after the hurdle were calculated directly off the film record. Support time was calculated
by determining the number of frames from touchdown to takeoff, and nonsupport time
by determining the number of frames from takeoff to touchdown. The remaining descriptors were identified from the processed digitized results. Horizontal velocity was defined
as the average velocity from touchdown in the hurdle stride to takeoff in the recovery
stride, while vertical velocity was the maximum positive (upward) velocity produced during the hurdle stride. Hurdle stride length was determined as the distance between the
touchdown points of the centers of gravity of the trail leg foot (takeoff) and lead leg foot
(touchdown).
Figures 1 and 2 identify the kinematic variables analyzed. The upper leg variables
investigated (Figure 1) included (a) ground leg angular velocity at touchdown of the hurdle
stride, (b) average ground leg angular velocity during ground contact of the hurdle stride,
WOMEN'S 100 METERS
Figure 1 - Upper leg kinematic variables: (a) ground leg angular velocity at touchdown of
the hurdle stride; (b)ground leg angular velocity during ground contact of the hurdle stride;
(c) ground leg angular velocity at touchdown of the recovery stride; (d) ground leg angular velocity
during ground contact of the recovery stride.
(c) ground leg angular velocity at touchdown of the recovery stride, and (d) average ground
leg angular velocity during ground contact of the recovery stride. The lower leg variables
of interest (Figure 2) included (a) lead leg minimum angular position during ground contact of the hurdle stride, (b) lead leg angular position when the ankle crosses the opposite
leg during ground contact of the hurdle stride, (c) ground leg angular velocity at touchdown
of the hurdle stride, (d) average ground leg angular velocity during ground contact of the
hurdle stride, (e) ground leg angular velocity at touchdown of the recovery stride, and
(0 average ground leg angular velocity during ground contact of the recovery stride.
The performance results of the upper and lower legs dictate the position and velocity of the foot during the performance. The two critical foot results occur at ground contact since the position and velocity dictate, to a large degree, the amount of horizontal
braking during the first half of ground contact. Figure 3 demonstrates this concept both
into and off the hurdle.
The identified results were selected since extensive information has been gathered
on these parameters for elite hurdlers (Mann et al., 1982-1983).The variables were original-
MANN AND HERMAN
Figure 2 - Lower leg kinematic variables: (a) lead leg minimum angular position during ground
contact of the hurdle stride; (b) lead leg angular position when the ankle crosses the opposite
leg during ground contact of the hurdle stride; (c) ground leg angular velocity at touchdown
of the hurdle stride; (d) ground leg angular velocity during ground contact of the hurdle stride;
(e) ground leg angular velocity at touchdown of the recovery stride; (f) ground leg angular velocity
during ground contact of the recovery stride.
WOMEN'S 100 METERS
Center
Figure 3 - Foot kinematic variables: (a) horizontal distance from the foot center of gravity
to the body center of gravity at touchdown of the hurdle stride; (b) horizontal velocity (with
respect to the body center of gravity) at touchdown of the hurdle stride; (c) horizontal distance
from the foot center of gravity to the body center of gravity at touchdown of the recovery stride;
(d) horizontal velocity (with respect to the body center of gravity) at touchdown of the recovery
stride.
ly chosen due to their importance as indicated by previous research, as well as coaches'
input. Since ihe initial selection, variables have been altered, deleted, or added as data
provided greater insight into the importance of the possible variables.
Results and Discussion
The results for the direct performance descriptors for the 100-meter hurdlers are presented
in Table 1. Table 2 presents the results for the body kinematics.
As in the previous sections, this section will focus first on the effects (direct performance variables), followed by the visible causes (body kinematics).
Direct Performance Variables
Although the direct performance variables do not indicate how the elite hurdler produces
a successful performance, they do provide information concerning the critical phases of
the activity. It is evident that the average horizontal velocity value into, over, and off the
hurdle is the best indicator of hurdle performance. The horizontal velocity results listed
in Table 1 indicate that, at the conclusion of the race, the Silver medalist held a slight
advantage over the Gold medalist in speed over the hurdle. Both medalists in turn held
an advantage over the 8th-place performer.
In elite athlete hurdlers, it has been found that better performers minimize the
maximum vertical velocity of the hurdle stride, and produce the result very close to the
takeoff point. In less successful hurdlers, additional vertical velocity is produced, and it
is generated earlier in the ground contact portion of the stride (Mam et al., 1982, 1983).
MANN AND HERMAN
Table 1
Direct Performance Descriptors
Performer
Variable
Gold
Silver
8th
Horizontal velocity (mls)
Vertical velocity (mls)
Hurdle stride length (m)
total
before hurdle
after hurdle
Hurdle times (s)
before hurdle (ground)
over hurdle (air)
after hurdle (ground)
Table 2
Body Kinematics
Performer
Variable
Gold
Upper leg velocity ( d e g l ~ ) ~
touchdown (into)
ground (into)
touchdown (off)
ground (off)
Lower leg velocity (deglslb
touchdown (into)
ground (into)
touchdown (off)
ground (off)
Foot distance at touchdown (m)
into
off
Foot velocity at touchdown ( m l ~ ) ~
into
off
- 3.80
- 6.49
Silver
- 5.06
- 8.20
8th
- .94
- 7.1 1
aNegative result indicates extension.
bNegative result indicates flexion, positive result indicates extension.
CNegativeresults indicate foot is moving backward in relation to the body center of gravity.
For the foot to be moving backward with respect to the ground, the velocity would have
to exceed the forward velocity of the performer.
WOMEN'S 100 METERS
171
Table 1 results support this conclusion with perfect correlation between vertical velocity
and place finish. The difference in velocity between the elite and the typical hiirdler can
be attributed to mechanics, with superior technique allowing the elite performer to clear
the barrier with a minimal increase in vertical projection over the normal sprint stride.
The difference in point of velocity production can be attributed to strength, with the weaker
performer being forced to produce the vertical velocity early in ground contact when the
leg can be used as a vaulting pole. This early vertical emphasisproduces unwanted horizontal
braking forces, which the elite hurdler minimizes by delaying the vertical emphasis until
late in the stride.
The remaining direct performance variables, which all contribute to the horizontal
and vertical velocities, indicate the importance of all aspects of hurdle clearance toward
the production of a successful overall performance. Although in the elite athlete hurdler
the stride length over the hurdle is minimized, Table 1 indicates no evident superiority
in this value or its division before and after the hurdle, for either of the three Olympic
hurdlers. The time results (Table 1) into, over, and off the hurdle do, however, reveal
a definite performance related trend. For the time results into (ground phase), over (air
phase), and off (ground phase) the hurdle, the Gold medalist demonstrated superior results
in all phases. The Silver medalist produced excellent results in all but the air phase, while
the last-place f i s h e r showed definite weakness in both ground phases. Thus, the difference
between the two top medals was determined in part over the hurdle, while a medal possibility
was lost by the eighth-place finisher, due in part to poor ground time results.
Body Kinematics
The legs are the critical body segments that produce the direct performance variables.
As in sprinting, upper leg movement during the stride into and off the hurdle is the most
critical variable in producing a successful performance. As Table 2 indicates, although
the upper leg angular velocity of the Gold medalist was low going into the hurdle, she
was the only performer with the strength and technique to improve the velocity during
ground contact. Coming off the hurdle, while both medalists produced typical values, the
last-place finisher produced superior results. Unfortunately, as will be seen, this strength
was negated by poor results in the lower leg results.
Although not as critical, poor lower leg movement results can greatly affect the
potential performance capabilities of a hurdler. Table 2 indicates that, going into the hurdle, only the Gold medalist produced the beneficial knee flexion at touchdown (to redtlce
horizontal braking) and overall extension (to drive the performer into the hurdle) during
ground contact. This result, coupled with the excellent upper leg velocities, provided the
winner with a decided advantage during this portion of the hurdle clearance. In contrast,
both the Silver medalist and the last-place finisher were extending the lower leg at
touchdown, increasing horizontal braking and increasing the ground time. Only the excellent lower leg result produced during ground contact saved the runner-up valuable time.
The last-place hurdler did not recover, resulting in the poor time on the ground result
going into the barrier.
Coming off the hurdle, the superior performer should have the lower leg flexing
at touchdown, and continue this action as the body is pulled forward (not upward) toward
the next hurdle. Of the three hurdlers, only the Silver medalist was able to produce this
result. The Gold medalist, although extending at touchdown, was able to quickly recover
and produce the beneficial flexion during ground contact. In contrast, the last-place finisher
MANN AND HERMAN
172
extended the lower leg both into and during ground contact. This very poor result completely negated the edge this performer had produced with the upper leg motion.
The foot position at touchdown going into and coming off the hurdle is dictated
by the movements of the upper and lower legs. As shown in Table 2, both medalists touched
down closer to the body both into and off the hurdle in comparison to the 8th-place finisher.
When coupled with the large foot velocity differences between the medalists and the 8thplace hurdler going into the hurdle, it is evident that this was where performance was
negatively affected to the greatest extent. At touchdown coming off the hurdle, the superior
upper leg results of the 8th-place finisher compensated sufficiently to bring the foot velocity
to parity with the two leading hurdlers.
Conclusions
From the filmed results of the 1984 Summer Olympic Games, it is evident that the factors
that dictate superior performance can be identified. In the analysis of the three 100-meter
hurdlers, the overall results clearly demonstrate the superiority of the more successful
performers. In summary, the differences in performance stemmed from the following:
1.
2.
3.
4.
5.
6.
7.
Higher horizontal velocity
Lower vertical velocity
Shorter support time
Higher upper leg velocity during support into and off the hurdle
Higher lower leg velocity during support into and off the hurdle
Superior foot position at touchdown into and off the hurdle
Higher (relative to the body) foot velocity at touchdown into the hurdle.
From the direct performance descriptors, it is evident that the two medalists demonstrated strong hurdle technique. The Gold medalist produced the quickest hurdle clearance,
while the Silver medalist produced superior horizontal velocity over the barrier. In contrast, the 8th-place finisher lost valuable time during ground contact both going into and
coming off the hurdle.
The body kinematics results indicated that the key to the Gold medalist's hurdle
performance was the ability to produce leg velocity during ground contact. In contrast,
the strength of the Silver medalist's technique was in preparation for ground contact. With
the exception of the upper leg results after the hurdle, the last-place hurdler failed to adequately prepare for touchdown or effectively use the ground contact time during the hurdle stride.
Hopefully, the availability of the films from the Games will produce expanded
results on these data, as well as results from the remaining sprint and distance events.
Such biomechanical data on elite performances of this nature offer the possibility of greater
understanding of the nature of the high performance human locomotion.
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WOMEN'S 100 METERS
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