3D Biomechanical Analysis of Women's High Jump Technique
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STUDY VIEWPOINT© by IAAF 3D Biomechanical Analysis 27:3; 31-44, 2012 of Women’s High Jump Technique by Vassilios Panoutsakopoulos and Iraklis A. Kollias ABSTRACT AUTHORS The purpose of the present study was to in- Vassilios Panoutsakopoulos is a PhD Can- vestigate the three-dimensional kinemat- didate in Biomechanics. He teaches Track ics of contemporary high jump technique and Field in the Department of Physical during competition and to compare the re- Education & Sports Science, Aristotle Uni- sults with findings from previous elite-level versity of Thessaloniki, Greece. events. The participants in the women’s high jump event of the European Athlet- Prof. Dr. Iraklis A. Kollias is the Director of ics Premium Meeting “Thessaloniki 2009” the Biomechanics Laboratory of the De- served as subjects. The jumps were re- partment of Physical Education & Sports corded using three stationary digital video Science, Aristotle University of Thessalon- cameras, operating at a sampling frequen- iki, Greece. His major fields of research are cy of 50fields/sec. The kinematic param- the 3D analysis of sports technique and the eters of the last two strides, the take-off development of specific instrumentation and the bar clearance were extracted for for sport analysis. analysis through software. The results in- dicated that the kinematic parameters of the approach (i.e. horizontal velocity, stride length, stride angle, height of body centre Introduction of mass) were similar to those reported in the past. However, a poor transformation urrently, most top high jumpers use of horizontal approach velocity to vertical one of the versions of the Fosbury take-off velocity was observed as a greater C Flop technique1. The technique, which deceleration of the swinging limbs could be comprises the approach, the preparation for seen at the instant of take-off. Consider- the take-off, the take-off, the flight phase and able backward lean at take-off, large take- bar clearance and the landing2, is differenti- off angle and inefficient bar clearance ated from the other jumping styles mainly by were also noted. The authors recommend the so called “J” approach and back lay-out that the athletes studied consider giving a position used to cross the bar. greater emphasis to the key technique ele- ments of the take-off phase and of the bar The single most important factor and es- clearance. sential contributor to the height cleared, is the height of the flight of the body’s centre of mass (BCM), which is a result of the vertical impulse produced during the take-off phase3,4. New Studies in Athletics · no. 3.2012 31 3D Biomechanical Analysis of Women’s High Jump Technique Key biomechanical factors that describe the Y-axis was parallel to the long side of the cross- take-off are the knee angle of the take-off leg, bar; the X-axis was perpendicular to the Y-axis; the angle of the lead leg thigh, the angle of the the Z-axis was perpendicular and vertical to the trunk position and the angles of forward/back- X- and Y-axes. The accuracy of the 3D recon- ward and inward lean4,5. struction was determined by Root Mean Square error. Errors of 2.5cm, 1.8cm and 1.5cm were The support and flight times, the stride lengths found for the X-, Y- and Z-axes, respectively. and frequencies, the path of the BCM, the angle of the run-up and the horizontal, vertical and re- Data Analysis sulting BCM velocities are the parameters that All trials above 1.84m were recorded and each are usually used to analyse the approach4,6,7,8. jumper’s highest valid jump was selected for fur- ther analysis. Eighteen anatomical points on the Research data for female high jumpers ex- body (tip of the toe, ankle, knee, hip, shoulder, el- ist from the Olympic Games7,9, IAAF World bow, wrist and fingers on both sides of the body, Championships in Athletics10,11,12, IAAF World the neck and the top of the head) and selected Junior Championships7 and IAAF World Indoor parts of the crossbar and the uprights were man- Championships9. Furthermore, data are also ually digitised in each field (Figure 1, page 33). available from longitudinal observations of elite The coordinates of the BCM were calculated for female high jumpers4,13,14,15,16. In the present every field using the segment parameters derived study, international level female high jumpers with the method proposed from PLAGENHOEF18. were analysed in order to observe the three- A 6Hz cut-off frequency, based on residual analy- dimensional kinematics of contemporary high sis19, was selected for smoothing. jump technique during competition and to compare the results with findings from previ- The coordinates of the digitised points were ous elite-level events. used for the calculation of the biomechanical parameters presented in this study. Spatial pa- Methods rameters (i.e. stride length, stride angle, BCM Subjects & Data Collection height) and the body configuration (i.e. joint angles and inclination of body segments) were The participants in the women’s high jump calculated using the extracted coordinates of of the European Athletics Premium Meeting the digitised points at selected time-instants of “Thessaloniki 2009” in Thessaloniki, Greece, the jumpers’ attempts. on 10 June 2009 served as the subjects. Video synchronisation, digitisation, smooth- All jumps were recorded using three station- ing and analyses were conducted using the ary JVC digital video-cameras (GR-DVL9600EG; A.P.A.S.-XP software (Ariel Dynamics Inc., Tra- GR-D720E; GR-D815; Victor Co., Japan), oper- buco Canyon, CA). Descriptive statistics (aver- ating at a sampling frequency of 50fields/sec. age ± standard deviation) were utilised for the The video-cameras were fixed on tripods and presentation of the results. were positioned on the stands (Figure 1). The synchronisation of the captured videos from the Results three video-cameras was accomplished with the use of the audio signals recorded, using the audio synchronisation method provided by the Seven jumpers cleared 1.84m, with the mean analysis software. official result being 1.90m (Table 1). Vlasic won the competition with a jump of 2.01m, the 16th 20 The area used by the jumpers for the ap- best result in 2009 . Four of the studied jump- proach and the take-off was calibrated by plac- ers (Vlasic, Radzivil, Stergiou, Forrester) used ing 2.5m ´ 0.02m poles at predefined spots on the the double-arm technique while the other three field, in order to produce three-dimensional coor- (Spencer, Dusanova, Klyugina) used running- dinates with the use of a 3D-DLT technique17. The arm technique. 32 New Studies in Athletics · no. 3.2012 3D Biomechanical Analysis of Women’s High Jump Technique Figure 1: The filming views, the digitizing process and the 3D reconstruction of Vlasic’s successful attempt at 2.01m using the APAS-XP software (Ariel Dynamics Inc., Trabuco Canyon, CA) Table 1: The height of the body centre of mass at the instants of touchdown and take-off (H0 and H1, respec- tively), the height of the flight (H2) and the height of bar clearance (H3), along with the maximum height 5 achieved (HMAX) (The values are also presented as percentage (%) of the official result (HOFF) ) New Studies in Athletics · no. 3.2012 33 3D Biomechanical Analysis of Women’s High Jump Technique The results indicate that almost one third ing the concentric phase of the take-off (36°). of the height of the jump was the actual flight. In contrast, Vlasic had the largest touchdown Radzivil and Stergiou better exploited their knee angle (151°), the largest minimum knee maximum flight height, since the bar was only angle (146°) and the second lowest range of 0.03m beneath the maximum point of their motion of the knee joint during the concentric BCM flight paths. Spencer, Klyugina and For- phase of the take-off (25°). Vlasic and Dusano- rester had the potential for a height closer to va almost extended their knee of the support 2.00m with ideal technique, since each was leg at the instant of take-off. On the contrary, able to lift her BCM more than 0.10m over the Radzivil took-off with a more flexed knee bar height at their best valid jump. (158°), since she executed the jump with the lowest range of motion of the knee joint during Stergiou and Klyugina took off nearer to the the concentric phase of the take-off (22°). end of the bar (less than 0.40m), while Vlasic and Forrester took off closer to the centre of Differences concerning the relationship of the bar (more than 1.1m from the end of the the magnitude of knee flexion of the take-off bar). With the exception of Radzivil and Klyu- leg and the development of vertical BCM ve- gina, the jumpers took-off about 0.9m away locity in the take-off phase among jumpers from the bar (Table 2). were detected. Figure 3a compares the de- velopment of vertical BCM velocity between Dusanova and Klyugina cleared the bar in Vlasic and Stergiou, who had the largest and the descending part of their BCM flight path, smallest touchdown and minimum knee angle, while Radzivil reached the highest point of her respectively. Figure 3b shows the development flight curve 0.21m behind the bar (Figure 2). of vertical BCM velocity between two jumpers (Spencer, Forrester) with almost equal knee The jumpers’ body configuration at the in- flexion, but different vertical take-off velocity stant of take-off is presented in Figure 2. With of the BCM. Figure 3c represents the altera- regard to the fulfilment of the key elements of tions of the development of vertical velocity of high jumping technique1,2,21,22 the following de- the BCM during the take-off phase among the viations were observed: jumpers who cleared 1.88m (Dusanova, Klyu- • the inadequate backward lean of the body gina, Stergiou).