kinematic analysis of jolanda ceplak’s running...

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23 New Studies in Athletics • no. 1/2004 © by IAAF 19:1; 23-31, 2004 STUDIES Kinematic analysis of Jolanda Ceplak’s running technique By Branko Skof, Stanko Stuhec AUTHORS Branko Skof and Stanko Stuhec work at the Faculty of Sport at the University of Ljubljana/Slovenia. Introduction olanda Ceplak's competitive performances during the 2002 and 2003 seasons certainly go down in the history of the 800 metres. She is the indoor world record holder (1:55.82) and her outdoor PB 1:55.19 is the seventh best performance of all times. Running technique contributes to the competitive edge of a long or middle distance runner. Efficient running biomechanics helps to keep injuries at bay and ensure that the runner's neuro-muscular potential is fully An elite runner’s running tech- nique is shaped by a number of physical characteristics, the influence of previous training (volume, methods of training) and racing. Hence, the running style of each individual is very specific. The purpose of this study is to point to some important kinematic variables of the run- ning stride of Jolanda Ceplak, the indoor world record holder over 800 metres. From the 3-D kine- matic analysis it is possible to draw the following conclusions: The plant is close to the vertical projection of the body's CM (cen- tre of mass). Vertical displace- ment of CM is optimal, which can help to improve running econo- my. Great plantar flexion range, high angular velocity of plantar flexion in the ankle joint and explosive knee extension enable Ceplak to produce a substantial propulsive force and adds to the length of her stride. The ampli- tude of the thigh swing of the swing leg is greater than this parameter in comparable studies. Several kinematic parameters of Ceplak's running are quite similar to parameters of longer sprint events (200m and 400m) espe- cially during the onset of fatigue. ABSTRACT J

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© by IAAF

19:1; 23-31, 2004

STUDIES

Kinematic analysis of Jolanda Ceplak’srunning techniqueBy Branko Skof, Stanko Stuhec

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Branko Skof and Stanko Stuhecwork at the Faculty of Sport at theUniversity of Ljubljana/Slovenia.

Introduction

olanda Ceplak's competitive performances during the 2002 and2003 seasons certainly go down in

the history of the 800 metres. She is theindoor world record holder (1:55.82) and heroutdoor PB 1:55.19 is the seventh bestperformance of all times.

Running technique contributes to thecompetitive edge of a long or middle distancerunner. Efficient running biomechanics helpsto keep injuries at bay and ensure that therunner's neuro-muscular potential is fully

An elite runner’s running tech-nique is shaped by a number ofphysical characteristics, theinfluence of previous training(volume, methods of training)and racing. Hence, the runningstyle of each individual is veryspecific. The purpose of this studyis to point to some importantkinematic variables of the run-ning stride of Jolanda Ceplak, theindoor world record holder over800 metres. From the 3-D kine-matic analysis it is possible todraw the following conclusions:The plant is close to the verticalprojection of the body's CM (cen-tre of mass). Vertical displace-ment of CM is optimal, which canhelp to improve running econo-my. Great plantar flexion range,high angular velocity of plantarflexion in the ankle joint andexplosive knee extension enableCeplak to produce a substantialpropulsive force and adds to thelength of her stride. The ampli-tude of the thigh swing of theswing leg is greater than thisparameter in comparable studies.Several kinematic parameters ofCeplak's running are quite similarto parameters of longer sprintevents (200m and 400m) espe-cially during the onset of fatigue.

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exploited. It also helps to save the energy,which in turn results in better racing.

An elite runner’s running technique isshaped by a number of physical characteris-tics such as flexibility, power, neuro-muscularfunction, body composition etc., the influenceof previous training (volume, methods oftraining) and racing. Hence the running styleof each individual is very specific. However,there are general modelling laws that deter-

mine optimal running stride, and these areimportant starting points in the teaching andimproving young runners' running technique.

The running cycle (double stride) consists ofthe support phase ("braking" phase: footstrike, midsupport and "propulsion" phase ortakeoff) and flight phase (follow-through orfloat, forward swing and foot descent).7

Studies show that running stride efficiency

Kinematic analysis of Jolanda Ceplak’s running technique

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depends to a large extent on how the runnerplants his or her foot and how he or she usesthe time during the support phase.1,5,10,11 This inturn affects the speed, the onset of tirednessand running economy.

The purpose of the study is to showkinematic parameters of Jolanda Ceplak'srunning cycle during the finishing stages ofthe 800m. We focused our attention onparameters that describe dynamic of supportphase.

MethodsWe studied the kinematic parameters of

Ceplak's running stride using a video of hercompetitive effort at European AthleticAssociation meeting held in Velenje. Herwinning time for the race was 1:59.52 (1st400m – 61.57, 2nd 400m – 57.95). Thekinematic analysis covers the distancebetween 738 and 743m of the race.

3D kinematic parameters were measuredwith two synchronised Sony DVCAM DSR-300PK cameras with a frequency of 50Hz. Thecameras had an internal synchronisationsystem. They were placed at an angle of 90°with respect to the object recorded. Spatialcalibration was done with eight referencepoints of two cubes with 1m sides.

For a 3-D kinematic analysis of runningtechnique, we used APAS kinematic systems(Ariel Dynamics Inc., USA) and our own software. CM (centre of mass) of separatebody segments and the total body CM werecalculated using a 15-segment anthropo-metric model.4 Using this model we studiedtrajectories, velocities, angles and angularvelocities of each point and segment. Allnumeric data were smoothed with a 7Hzdigital filter.

Results and discussionThe basic aim of this study was to define

and show the stride cycle kinematic parameters that influence the efficiency ofCeplak’s running to the greatest extent.

The results (see Figures 1-4 and Table 1)show basic kinematic variables of Ceplak'srunning stride as she is coming off the lastturn and into the finishing straight. Runningvelocity at this stage was 7.10m/s1. Averagestride length was 197cm, but in the sectionanalysed it varied from 190 to 204cm.Relative stride length (stride length / heightof body) was 1.17m. Stride frequency was3.6Hz.

Figure 1: Kinematic parameters of runningstride -footstrike

An important factor of efficient runningtechnique is a support phase generating aslittle deceleration as possible. The brakingphase must be as short as possible. A shortbraking phase and only a slight brakingimpulse of the ground reaction force (very littleloss of horizontal velocity) can be achieved byplanting the foot close to the verticalprojection of the body's CM on the ground (seeFigure1). The distance between the firstcontact and the projection of the CM must beas short as possible; at the same time, theangle of foot placement on the ground mustnot be too narrow. The distance of 0.32m atfoot strike is similar to corresponding values ofother top female runners: Cathy Freemanduring a 200m race (average velocity 8.44m/s-1),Marita Koch (0.28m) and Jarmila Kratochvilova

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Kinematic analysis of Jolanda Ceplak’s running technique

(0.27m) in a 400m race (velocity 7.77/8.12m/s-1). The angle of 70° at foot strike wasalso similar2,9. In comparison to sprinting, thedistance between foot strike and verticalprojection of body's CM is much longer whilethe angle of foot plant is narrower.3

Figure 2: Kinematic parameters of runningstride – midsupport

Apart from the method of planting the foot,the contact time and the appropriateness ofthe evaluation angle in the takeoff alsodepend on the execution of midsupport andthe swing of the swing leg.

The braking phase and takeoff, whichrepresent eccentric-concentric muscularcontractions at the ankle, knee and hip joints,represent the phase of converting the runner'spotential energy into kinetic energy.6

During the braking phase, suitable pre-activation and muscle stiffness enable therunner to keep the range of dorsal flexion ofthe ankle, as well as knee and hip flexion, assmall as possible and the braking phase asshort as possible (see Figures 2 and 4).

Figure 3: Kinematic parameters of runningstride – takeoff

Despite tiredness in the closing stages ofthe 800m race, the ranges of dorsal flexion ofthe ankle at 21° and knee flexion at 7° (thewidest angle of knee flexion during thesupport phase is 30°) are relatively very smalland comparable (20° and 9°) to thecorresponding ranges of top female runners inthe closing stages (onset of fatigue) of a400m race.9

This rather slight “give” in the ankle andknee joints points to the runner maintainingneuro-muscular potential (the ability tomaintain muscle stiffness) even with theonset of tiredness. Over the running cycle thehips remain tall, which is reflected in the wideangle (165°) between the trunk and the thighof the support leg in the braking phase.

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4Kinematic analysis of Jolanda Ceplak’s running technique

From the magnitude of ankle plantarflexion at takeoff (80°), the high angularvelocity of the foot (1374°/s-1), a high angularvelocity (more than 1000°/s-1) and accelerationin the knee extension, a high forward swingof the recovery leg (63°), the takeoff angle of62° (the angle between the lower leg and theground) and the evaluation angle (7°), we candraw the conclusion that this runner's takeoffaction is very efficient and explosive (seeFigures 3 and 4). The values are comparable

with the parameters of Cathy Freeman'ssprinting and with the results of a group ofelite middle distance runners.2,8

The movement of the swing leg significantlycontributes to a runner's efficiency. The swingleg (thigh, lower leg and foot) is the onlysegment which in the braking phase of therunning stride produces the propulsive forceacting in the direction of running.2,12 Efficientrunning stride is determined both by the

Figure 4: Angles (above) and hip, knee and ankle angular velocity (below) of Jolanda Ceplak'srunning stride (left leg)

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speed of the swing leg, especially the foot,and the trajectory of the foot.

The speed of the swing leg foot during thebraking phase is determined by an explosivetakeoff and the runner's relaxation, whichcontribute to a greater range of knee flexionof the swing leg. This enables the foot tomove at high speed as close to the thigh (but-tocks) as possible. A shorter lever enhancesthe swing leg velocity and transition fromfollow-through to forward swing.

At footstrike, the horizontal velocity of theswing foot was 11.90m/s-1 and during forwardswing it reached its peak with 14.25m/s-1 (seeFigure 5). These values are comparable withfoot velocities in longer sprint events (200m

Table 1: Kinematic parameters of 800 metresrunning – Jolanda Ceplak

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and 400m) - particularly in conditions offatigue. In the 200m, Cathy Freeman'srecovery leg foot velocity at footstrike of theopposite leg was 13.80m/s-1 while in theforward swing phase it was 14.72m/s-1. Thebest Slovene sprinters (100m) recorded13.03m/s-1 and 16.30m/s-1 respectively.2,3

The efficiency of Ceplak's follow-through isreflected in the high position of her foot and

a very narrow angle in the flexed knee (148°)of the swing leg in the midsupport (see Figure1 and Table 1).

An important parameter of running economyis vertical displacement of the body's CM. Theapex of the trajectory of the body's CMdepends mainly on the takeoff angle (thenarrower the better) and the relationshipbetween the vertical and horizontal velocities

Figure 5: Horizontal (above) and vertical velocity (below) of CM, of Jolanda Ceplak’s left andright feet

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of the CM at push-off. Ceplak's ver-tical displacement of CM is0.08m (see Fig. 6); simi-lar to Cathy Freeman(0.08m) and a group ofelite female middledistance runners(0.076m).2,12

ConclusionStrength and power training is reflected in

the technique of 800m runners. Several kine-matic variables of 800m running appear to bequite similar to the parameters of longersprint events, particularly in conditions offatigue.

On the basis of the kinematic analysis ofJolanda Ceplak's running, we can draw thefollowing conclusions:

◆ Foot strike is close to the vertical of thebody's CM. This minimises horizontalvelocity loss during the braking phase ofthe support phase.

◆ Low degree of amortization in midsupport(dorsal flexion of the foot and knee flex-ion in the braking phase of the supportphase) indicates the runner's ability tomaintain neuro-muscular potential(maintenance of muscle stiffness) evenwhen tired.

◆ A substantial plantar flexion range andhigh angular speed of ankle plantar flex-ion and knee extension enable the runnerto produce a greater propulsive force andcontribute to the increased length of herstride.

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Kinematic analysis of Jolanda Ceplak’s running technique

Figure 6: Vertical displacement of body’s CM during running stride

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References

1. CAVANAGH, P. R. & KRAM, R. (1989):Stride length in distance running. Medicineand Science in Sports and Exercise, 14(4),308-316.

2. KOH, M.; KLAVORA, P. & TAHA, T. (2002):Cathy Freeman - Biomechanical character-istics of sprinting technique. In M. Koh (Ed.),Application of Biomechanics in Track andField (pp. 51-58). Ljubljana: University ofLjubljana.

3. KOH, M. & KAMPMILLER, T. (2002): Kine-matic and dynamic parameters of thesprinting stride. In M. Koh (Ed.), Applicationof Biomechanics in Track and Field (pp. 43-50). Ljubljana: University of Ljubljana.

4. DEMPSTER, W. (1955): Space require-ments of the seated operator. In WADCTechnical Report, (pp. 55 – 159). Ohio:Wright-Patterson Air Force Base.

5. DERRICK, T. R.; DEREU, D. & MCLEAN, S. P.(2002): Impact and kinematic adjustmentsduring an exhaustive run. Medicine and Sci-ence in Sports and Exercise, 34(2), 998-1002.

6. FREDERICK, E. C. (1983): The Energy Costof Load Carriage on the Feet During Run-ning. In D. A. Winter, R. W. Norman, R. P.Wells, K. C. Hayes and A. E. Patla (Eds), Bio-mechanics (pp. 295-307).Waterloo: Canada.

7. MANN, R. A.; MORAN, G. T. & DOUGHER-TY, S. E. (1986): Comparative electromyogra-phy of the lower extremity in jogging, run-ning, and sprinting. Am. J. of Sports Medi-cine, 14(6), 501- 510.

8. MARTIN, D. E. & COE, P. (1991): Trainingdistance running. Champaign, IL: HumanKinetics.

9. MERO, A.; LUHTANEN, P.; KOMI, P. V. &SUSANKA, P. (1988): Kinematics of TopSprint (400 m) Running in Fatigued Condi-tions. Track Field Q Rew, 74(1), 42-45.

10. MERO, A.; KOMI, P. V., & GREGOR, R.J.(1992): Biomechanics of Sprint Running.Sport Medicine, 13(6), 376-392.

11. SKOF, B. & DOLENEC, A. (1999): EMGactivity and ground reaction forces during3-km run.In V. Strojnik and A. Usaj (Eds),Theories of Human Motor Performance andtheir Reflections in Practice (Proc. 6th SportKinetics Conference)(pp 375-380). Ljubl-jana: Slovenia.

12. WILLIAMS, K. R. (1993): Biomechanics ofdistance running. In M. D. Grabiner (Ed.),Current Issues in Biomechanics (pp. 3-31).Champaign: Human Kinetics.

◆ Amplitude and angular velocity of theswing thigh as well as the overall range ofthe thigh movement are greater than theranges recorded in comparable studies.Rear swing (recovery), i.e. transfer of thetakeoff leg during the flight, is also veryefficient.

◆ Vertical displacement is optimal, whichcan helps to enhance running economy.

Please send all correspondence to:Branko Skof, Ph.D.University of Ljubljana,Faculty of sportGortanova 221000 Ljubljanae-mail: [email protected]

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